{"id":31106,"date":"2020-03-28T10:40:59","date_gmt":"2020-03-28T10:40:59","guid":{"rendered":"http:\/\/biomedpharmajournal.org\/?p=31106"},"modified":"2020-04-22T12:14:34","modified_gmt":"2020-04-22T12:14:34","slug":"comparative-inotropic-effects-of-the-some-isoquinoline-alkaloids","status":"publish","type":"post","link":"https:\/\/biomedpharmajournal.org\/staging\/vol13no1\/comparative-inotropic-effects-of-the-some-isoquinoline-alkaloids\/","title":{"rendered":"Comparative Inotropic Effects of the Some Isoquinoline Alkaloids"},"content":{"rendered":"<p><strong>Introduction<\/strong><\/p>\n<p>In the world, there has been a trend towards the spread of cardiovascular diseases in recent years, which continues to be a leader in general disease and death structure<sup>1,2<\/sup>. Worldwide, cardiovascular diseases are a major problem in the medical, social and economic context, leading to disability and premature deaths<sup>3,4,5<\/sup>. According to the World Health Organization&#8217;s statistical data, about 17,300,000 people die of cardiovascular diseases each year and makes up ~31% of all deaths under general conditions<sup>6,1<\/sup>.<\/p>\n<p>Cardiovascular disease is associated with dysfunctional changes in cardiomyocytes [\u0421\u0430<sup>2+<\/sup>]<em><sub>in<\/sub><\/em> homeostasis, and myocardial rhythmic activity is provided by the function of \u0421\u0430<sup>2+<\/sup> transport system, located in the cardiomyocyte sarcolemma and sarcoplasmic reticulum (SR) membrane. \u0421\u0430<sup>2+<\/sup> entrance to potassium-activating L-type Ca<sup>2+ <\/sup>-channel (Ca<sup>2+<\/sup><sub>L<\/sub>-channel) in the sarcolemma during the formation of Na<sup>+<\/sup> -channel activation and action potential (AP) in Cardiomyocyte activates CR Ca<sup>2+<\/sup> -channel (RyR2; ryanodine receptor type 2). Ca<sup>2+<\/sup> affinity (Ca<sup>2+<\/sup> -spark) type cardiomyocytes cytosol increases the concentration of Ca<sup>2+<\/sup> and ions Ca<sup>2+<\/sup> in troponin-C in myocardium. Myocardial contraction is resulted by increases of \u0421\u0430<sup>2+ <\/sup>concentration in \u0421\u0430<sup>2+<\/sup>\u2013oscillation (\u0421\u0430<sup>2+<\/sup>\u2013spark) type cardiomyocytes cytosol and further formation with troponin-\u0421 in the myofilament. \u00a0During the diastole, \u0421a<sup>2+<\/sup> are normalized by \u0421a<sup>2+<\/sup> -ATPase (SERCA2a, Sarco (endo) plasmic reticulum calcium-ATPase type 2) in the sarcoplasmic reticulum membrane and Na<sup>+<\/sup>\/Ca<sup>2+<\/sup> -exchanger type 1 function. These ion-transport systems are at the center of the normal physiological function of myocardium. Breakage in function of these systems in cardiomyocytes leads to disruption of [\u0421a<sup>2+<\/sup>]<sub>in<\/sub> dynamics and development of arrhythmia-type cardiopathology<sup>7,8,9<\/sup>. The effect of &#8220;<em>target<\/em>&#8221; on effective antiarrhythmic and cardiotropic drugs, currently used in clinical cardiology practice, is directed to the pharmacological correction of the function of these systems (Figure 1).<\/p>\n<table border=\"1\" cellpadding=\"5\">\n<tbody>\n<tr>\n<td><img decoding=\"async\" class=\"alignnone size-thumbnail wp-image-31108\" src=\"https:\/\/biomedpharmajournal.org\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_fig1-150x150.jpg\" alt=\"Figure 1: Chemical structure of isoquinoline alkaloids.\" width=\"150\" height=\"150\" srcset=\"https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_fig1-150x150.jpg 150w, https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_fig1.jpg 596w\" sizes=\"(max-width: 150px) 100vw, 150px\" \/><\/td>\n<td><strong>Figure 1<\/strong><strong>:<\/strong><strong> Chemical structure of <\/strong><strong>isoquinoline alkaloids<\/strong><strong>.<\/strong><\/p>\n<p><a href=\"http:\/\/biomedpharmajournal.org\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_fig1.jpg\" target=\"_blank\">Click here to View Figure<\/a><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The disorders in the RyR2 structure have been reported to cause cardiac dysfunction and arrhythmias<sup>10<\/sup>.<\/p>\n<p>Specifically, increase in the spontaneous activation of RyR2, as well as increases of [Ca<sup>2+<\/sup>]<em><sub>in<\/sub><\/em> concentration induced by hyperphosphorylation of RyR2 through \u03b2\u2013AR \u2013 PKA and the development of pathogenesis of post-depolarization-type arrhythmia were established<sup>11<\/sup>.<\/p>\n<p>The RyR2 functional activity is regulated mainly by three mechanisms: [Ca<sup>2+<\/sup>]<em><sub>SR<\/sub><\/em>, [\u0421\u0430<sup>2+<\/sup>]<em><sub> in<\/sub><\/em> concentration changes, and by regulatory proteins and adaptive mechanisms regulated by RyR2 activation\/inactivation<sup>12<\/sup>.<\/p>\n<p>In \u03b2\u2013AR\u2013 [cAMF] in-PCA reactions cascade, under the effect of cervical oscillation of RyR2-FKBP12.6, RyR2 activity increases; thereby the probability of formation of arrhythmia rises<sup>13<\/sup>.<\/p>\n<p>Adenylate cyclase (A\u0421) and protein kinase A (PCA) system are important in the functional activity of cardiomyocytes.<\/p>\n<p>In the case of \u03b2\u2013adrenoreceptor (B-AR) activation in cardiomyocytes sarcolemma, A\u0421 enzyme activation via guanine-dependent activating transmembrane G<sub>s<\/sub>-protein (guanine nucleotide-binding proteins) and [\u0441AMF] value increase. PCA is activated by cAMF, and functional protein molecules including PLB, troponin-I, Ca<sup>2+<\/sup><sub>L<\/sub>-channel are phosphorylated<sup>14,15<\/sup>.<\/p>\n<p>Regulating the functional activity of cardiomyocytes through the modulation of the above-mentioned mechanism is significant to establish mechanism of action of biologically active substances, creation of potential pharmaceutical preparations on their basis, and treatment\/prevention of cardiopathology.<\/p>\n<p>Among chemical compounds, containing heterocyclic structure, isoquinoline alkaloids are characterized by a wide range of physiological spectra. Isoquinoline alkaloids possess antiarrhythmic and cardiotropic effects on cardiovascular system, spasmolytic, pain-relieving and anti-inflammatory effects<sup>16,17<\/sup>. Spasmolytic drugs included in the list of isoquinoline alkaloids, such as Papaverine and No-Shpa, are widely used in medical practice. Besides, papaverine analogs &#8211; salsolin, salsolidin, guanethidine, have a strong hypotensive effect<sup>18<\/sup>.<\/p>\n<p>The berberine (Berberine) isoquinoline alkaloid derived from <em>Rhizoma Coptidis<\/em> plant species has been reported to possess activity against pathogenic bacteria, ischemia, and thrombus formation, and hepatoprotective and antiarrhythmic effects<sup>1<\/sup><sup>9<\/sup>.<\/p>\n<p>Aim of this study was to establish mechanism of action of 1-(4-dimethylaminophenyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline (F-24), 1-(2-chloro-4,5-methylenedioxyphenyl)-2-hydroxyethyl-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline (N-14) and 1-(2-\u0441hloro-4,5-methylenedioxyphenyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline (F-14) alkaloids on cardiomyocytes ion- transport systems, by registering papillary muscular contraction activity of rat heart, <em>in vitro<\/em> conditions.<\/p>\n<p><strong>Material and<\/strong> <strong>Methods<\/strong><\/p>\n<p><strong>Solvents and Chemicals<\/strong><\/p>\n<p>All reagents, used in experiments, were of analytic\u2013grade (NaCl, KCl, CaCl<sub>2<\/sub>, MgSO<sub>4<\/sub>, KH<sub>2<\/sub>PO<sub>4<\/sub>, glucose, NaHCO<sub>3<\/sub>). (\u00b1)-propranolol hydrochloride, nifedipine hydrochloride, forskolin, phorbol 12-myristate 13-acetate (PMA), caffeine were obtained from Sigma Chemical (St. Louis, Missouri, USA).<\/p>\n<p>Isoquinoline alkaloids, the effects of which were studied, were synthesized by researchers group from the Institute for Plant Substances of Academy of Sciences of Uzbekistan.The isoquinoline alkaloids were synthesized on the basis of the Pictet -Spengler, and Bischler-Napieralski reactions. The chemical structures of the synthesized isoquinoline alkaloids were established using IR and NMR N<sup>1<\/sup> spectroscopy.<\/p>\n<p><strong>Tissue Preparation and Measurement of Contractility <\/strong><\/p>\n<p>In the experiments, the standard mechanography was used to screen the inotropic effect of isoquinoline alkaloids.<\/p>\n<p>The prepared papillary muscle was connected to a force transducer for signal recording. In experiments, the papillary muscle preparations were isolated from the right atrium of adult albino rats\u2019 hearts. The papillary muscles were 0.4\u20131.3 mm in diameter and 2.5\u20133.8 mm in length. The papillary muscles samples were prepared according to Sonnenblick, and the muscle was placed in a special horizontal tissue chamber (Type 813; Hugo Sachs Elektronik, March-Hugstetten, Germany), designed for <em>in vitro<\/em> study in standard pharmacological experiments for measuring contraction force response of papillary muscle preparations. The top of the system was open and it is provided with the organ chamber, volume \u2013 5 ml, the Thermo\u2013circulator for flow heater physiological solution and the wire holder for the force transducer (Type F30\/Model D-79232; Hugo Sachs Elektronik, March-Hugstetten, Germany), with a precision micrometer control. In the experiments, modified the physiological Krebs\u2013Henseleit solution containing (in mM): 118 NaCl; 4.7 KCl; 2.5 CaCl<sub>2<\/sub>; 1.2 MgSO<sub>4<\/sub>; 1.1 KH<sub>2<\/sub>PO<sub>4<\/sub>; 5.5 glucose and 25 NaHCO<sub>3<\/sub>; pH 7.4 were used. This Krebs-Henseleit solution which was continuously bubbled with 95% O<sub>2 <\/sub>and 5% CO<sub>2<\/sub> and kept at a temperature of +36\u00b10.5 \u00b0C by means of water heating system controlled by temperature controller U8 (Bulgaria), and flowed in and out of the organ bath at a rate of 3-5 ml\/min with the peristaltic pump LKB Bromma (Sweden).<\/p>\n<p>The isometric force transducer F30 was connected to a transducer amplifier (Type TAM-A; Hugo Sachs Elektronik, Harvard Apparatus GmbH, Germany). The papillary muscle was lifted with electric impulses higher than a threshold (~20%), rectangular, electrical pulses of frequency 0.5 Hz; 5 ms and 5 V amplitude, delivered via a pair of platinum electrodes placed in the muscle-mounting organ chamber by using stimulator ESL-2 (Russia). Thus, wires of a pair of platinum electrodes were placed as parallel to the organ; the physiological solution of Krebs-Henseleit provided shortening the electrical contact distance between the electrodes and the preparation of the papillary muscles. After 60 min of incubation period, papillary muscles were stimulated by an initial electrical pulse of frequency 0.5 Hz, amplitude 5 V, and 5 msec pulses. The obtained signals were given from the transducer F30 to amplifier and sent to a computer by using a pen chart recorder (Type TZ 4620; Czech Republic) or a personal computer with analog-digital converter LabPro Logger Lite 1.2 software (Vernier Software &amp; Technology, Beaverton, USA).<strong>\u00a0<\/strong><\/p>\n<p><strong>Data Analysis<\/strong><\/p>\n<p>Papillary muscle contractions were plotted as a percentage of the force before the drug application in each muscle. Data were analyzed by OriginPro 7.0 (MicroCal Software, Northampton, MA). Pooled data were given as means \u00b1S.E.M. of observations (<em>n<\/em>). Concentration-response curves were fitted to the logistic equation: , where <em>E<sub>max<\/sub> <\/em>\u2013 is the maximum effect, <em>k<\/em> \u2013 is a factor which represents the slope of the curve, and <em>pD<sub>2<\/sub><\/em> \u2013 is the drug concentration exhibiting 50% of the <em>E<sub>max <\/sub><\/em>expressed as negative log molar. Values are expressed as mean \u00b1S.E.M. The values were considered as significantly different when <em>p<\/em>&lt;0.05.<strong>\u00a0<\/strong><\/p>\n<p><strong>Results and Discussion<\/strong><\/p>\n<p><strong>Inotropic Action of Isoquinoline Alkaloids<\/strong><\/p>\n<p>The alkaloids of F-24 (10-60 \u00b5M), F-14 (5 to 40 \u00b5M) and N-14 (5 to 25 \u00b5M) isoquinoline in the experiments showed a negative inotropic effect on the papillary muscle contraction. Pupillary muscle contraction force decreased up to 92.4\u00b13.8%, 72.7\u00b14.4% and 66.5\u00b13.3% respectively. Semi-maximum concentrations of F-24, N-14 and F-14 alkaloids (IC<sub>50<\/sub>) were established to be 15.1 \u00b5M, 18.6 \u00b5M, and 23.9 \u00b5M, respectively (Figure 2).<\/p>\n<table style=\"width: 70%;\" border=\"1\" cellpadding=\"5\">\n<tbody>\n<tr>\n<td><img decoding=\"async\" class=\"alignnone size-thumbnail wp-image-31109\" src=\"https:\/\/biomedpharmajournal.org\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig2-150x150.jpg\" alt=\"Figure 2: Negative inotropic effect of isoquinoline alkaloids.\" width=\"150\" height=\"150\" srcset=\"https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig2-150x150.jpg 150w, https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig2-256x256.jpg 256w, https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig2.jpg 526w\" sizes=\"(max-width: 150px) 100vw, 150px\" \/><\/td>\n<td><strong>Figure <\/strong><strong>2<\/strong><strong>: Negative inotropic effect of isoquinoline alkaloids.<\/strong><\/p>\n<p><a href=\"http:\/\/biomedpharmajournal.org\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig2.jpg\" target=\"_blank\">Click here to View Figure<\/a><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The ordinate axis shows the pulsating force of the papillary muscle, expressed as a percentage of the maximum value of 100%. The stimulation frequency is 0.5 Hz (<em>t<\/em>=+36\u00b10.5\u00baC). <em>\u0420<\/em>&lt;0.01 (n=3-4).<\/p>\n<p><strong>\u00a0<\/strong><strong>T<\/strong><strong>he Role of Ca<sup>2+<\/sup><sub>L<\/sub>-Channels in the Inotropic Effect of Isoquinoline Alkaloids<\/strong><\/p>\n<p>Many negatively inotropic agents cause the Ca<sup>2+<\/sup><sub>L<\/sub>-channel blocking in cardiomyocytes to reduce the concentration of [Ca<sup>2+<\/sup>]<em><sub>in<\/sub><\/em> the cytosol<sup>20<\/sup>. Therefore, in recent experiments, we have investigated negative inotropic effects of F-24, N-14, F-14 alkaloids in the current state of the Ca<sup>2+<\/sup><sub>L<\/sub>-channel blocker nifedipine (<em>IC<\/em><sub>50<\/sub>=0,01 \u00b5\u041c) in the incubation medium. The negative effect of isoquinoline alkaloids: F-24 (15.1 \u03bcM), N-14 (18.6 \u03bcM) and F-14 (23.9 \u03bcM) in nifedipine (0.01 \u03bcM) containing incubation medium compiled 44.7\u00b16.3%, 39.7\u00b14.1% and 33.7\u00b13.3% respectively (Figure 3).<\/p>\n<table style=\"width: 70%;\" border=\"1\" cellpadding=\"5\">\n<tbody>\n<tr>\n<td><img decoding=\"async\" class=\"alignnone size-thumbnail wp-image-31110\" src=\"https:\/\/biomedpharmajournal.org\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig3-150x150.jpg\" alt=\"Figure 3: Comparison of the inotropic effects of F-24, N-14, F-14 alkaloids and nifedipine on the contraction force of extracted rat papillary muscle\" width=\"150\" height=\"150\" srcset=\"https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig3-150x150.jpg 150w, https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig3-256x256.jpg 256w, https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig3.jpg 624w\" sizes=\"(max-width: 150px) 100vw, 150px\" \/><\/td>\n<td><strong>Figure 3: Comparison of the inotropic effects of F-24, N-14, F-14 .<\/strong><\/p>\n<p><a href=\"http:\/\/biomedpharmajournal.org\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig3.jpg\" target=\"_blank\">Click here to View Figure<\/a><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>Stimulation: 0.5 Hz, 5 V, 5 msec, +36\u00b10.5 \u00b0C, resting tension = 10 mN. <em>P&lt;0.05<\/em> indicates value compared to control.<\/p>\n<p>The results show, that negative effects of F-24, N-14, F-14 alkaloids, in partial correlation, blockade Ca<sup>2+<\/sup><sub>L<\/sub>-channel in cardiomyocytes<strong>\u00a0<\/strong><\/p>\n<p><strong>The Cascade of \u03b2\u2013AR\u2013AC Reactions in the Inotropic Action of Isoquinoline Alkaloids<\/strong><\/p>\n<p>Proteinasease A (PCA) in cardiomyocytes is regulated by phosphorylation of functional protein macromolecules, for example, by the phosphorylation of PCA, RyR2 is activated and the value of [\u0421\u0430<sup>2+<\/sup>]<em><sub>in<\/sub><\/em> cytosol increases<sup>21<\/sup>. Cardiomyocyte protein kinase A \u2013 linked molecule (AKAP, A-kinase-anchor protein) ensures that signal transduction via PCA is performed correctly and the presence of mACAP (muscle-specific AKAP) molecules in the RyR2 phosphorylation<sup>22<\/sup>. The Beta-adrenergic receptors (\u03b2-ARs) stimulation enhances contractility through protein kinase-A (PKA) substrate phosphorylation. This PKA signaling is conferred in part by PKA binding to A-kinase anchoring proteins (AKAPs). AKAPs coordinate multi-protein signaling networks that are targeted to specific intracellular locations, resulting in the localization of enzyme activity and transmitting intracellular actions of neurotransmitters and hormones to its target substrates. In particular, mAKAP (muscle-selective AKAP) has been shown to be present on the nuclear envelope of cardiomyocytes with various proteins including PKA-regulatory subunit (RII\u03b1), phosphodiesterase-4D3, protein phosphatase-2A, and ryanodine receptor<sup>2<\/sup><sup>3<\/sup>.<\/p>\n<p>In further experiments, on the basis of inotropic effects on the papillary muscular contraction in the rats, we studied the putative effects of isoquinoline alkaloids (F-24, N-14, and F-14) on \u03b2\u2013\u0410R\u2013\u0410C reactions cascade.<\/p>\n<p>It has been revealed, that the positive inotropic effects of adenylate cyclase activator &#8211; forscolin (10 \u03bcM) decrease for 8.1\u00b12.4%, 39.3\u00b16.4% and 87.6\u00b15.2% by F-24 (<em>I<\/em><em>C<\/em><em><sub>50<\/sub><\/em>=15.1 \u03bcM), F-14 (<em>I<\/em><em>C<\/em><em><sub>50<\/sub><\/em>=23.9 \u03bcM) and N-14 (<em>I<\/em><em>C<\/em><em><sub>50<\/sub><\/em> = 18.6 \u03bcM) alkaloids, respectively (Figure 4).<strong>\u00a0<\/strong><\/p>\n<table style=\"width: 70%;\" border=\"1\" cellpadding=\"5\">\n<tbody>\n<tr>\n<td><img decoding=\"async\" class=\"alignnone size-thumbnail wp-image-31111\" src=\"https:\/\/biomedpharmajournal.org\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig4-150x150.jpg\" alt=\"Figure 4: Adenilate cyclase (AC) activator isotropic effect of isoquinoline sequence alkaloids (F-24,N-14, F-24) in current conditions of forscolin (1 \u00b5M).\" width=\"150\" height=\"150\" srcset=\"https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig4-150x150.jpg 150w, https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig4-256x256.jpg 256w, https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig4.jpg 644w\" sizes=\"(max-width: 150px) 100vw, 150px\" \/><\/td>\n<td><strong>Figure 4<\/strong><strong>:<\/strong><strong> Adenilat<\/strong><strong>e <\/strong><strong>c<\/strong><strong>y<\/strong><strong>clase (A<\/strong><strong>C<\/strong><strong>) activator isotropic effect of iso<\/strong><strong>quin<\/strong><strong>oline sequence\u00a0<\/strong><\/p>\n<p><a href=\"http:\/\/biomedpharmajournal.org\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig4.jpg\" target=\"_blank\">Click here to View Figure<\/a><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The ordinate axis shows the pulsating force of the papillary muscle, expressed as a percentage of the maximum value of 100%. The stimulation frequency is 0.5 Hz (t=36\u00b10.5\u00baC). * \u2013 <em>p<\/em> &lt;0.05, ** \u2013 <em>p<\/em> &lt;0.01 (n=4-5) for control.<\/p>\n<p>The inotropic effect of isoquinoline alkaloids (N-14, F-14, and F-24) in the medium of \u03b2-AR blocker propranolol (10 \u03bcM) + AC activator forskolin (<em>IC<sub>50<\/sub> <\/em>= 3.4 \u03bcM) on AT-activation in cardiomyocytes. It was registered that under the effects of forskolin (<em>I\u0421<sub>50<\/sub><\/em>=3.4 \u03bcM), in the medium propranolol (10 \u03bcM) incubation, the \u03b2-AR blocker, papillary muscle contraction activity significantly increased by 23.2\u00b13.5%, compared to control. The alkaloids N-14 (<em>IC<sub>50<\/sub><\/em>=18.6 \u00b5M), F-14 (<em>IC<sub>50<\/sub><\/em>=23.9 \u00b5M) and F-24 (<em>IC<sub>50<\/sub><\/em>= 15.1 \u00b5M) reduced propranolol (10 \u00b5M) + forskolin (<em>I\u0421<sub>50<\/sub><\/em>=3.4 \u03bcM) influence by 2.8\u00b12.3%, 13.5\u00b13.4% and 69.5\u00b16.2%, respectively (Fig. 5).<\/p>\n<table style=\"width: 70%;\" border=\"1\" cellpadding=\"5\">\n<tbody>\n<tr>\n<td><img decoding=\"async\" class=\"alignnone size-thumbnail wp-image-31112\" src=\"https:\/\/biomedpharmajournal.org\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig5-150x150.jpg\" alt=\"Figure 5: The inotropic effect of isoquinoline alkaloids (F-24, N-14, F-24) in the conditions of incubation of \u03b2-\u0410\u0420 blocker propranolol (10 \u03bcM) + forskolin (IC50=3, 4 \u03bcM).\" width=\"150\" height=\"150\" srcset=\"https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig5-150x150.jpg 150w, https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig5-256x256.jpg 256w, https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig5.jpg 630w\" sizes=\"(max-width: 150px) 100vw, 150px\" \/><\/td>\n<td><strong>Figure<\/strong><strong> 5<\/strong><strong>:<\/strong><strong> The inotropic effect of iso<\/strong><strong>qui<\/strong><strong>nolin<\/strong><strong>e<\/strong><strong> alkaloids (F-24, N-14, F-24)\u00a0<\/strong><\/p>\n<p><a href=\"http:\/\/biomedpharmajournal.org\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig5.jpg\" target=\"_blank\">Click here to View Figure<\/a><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The ordinate axis shows the pulsating force of the papillary muscle, expressed as a percentage of the maximum value of 100%. The stimulation frequency is 0.5 Hz (t =36\u00b10.5\u00baC). * \u2013for control ** \u2013 <em>\u0440<\/em>&lt;0.01 (n=5-6).<\/p>\n<p>In the case of incubation of propranolol (10 \u00b5M) + forskolin (IC50 = 3,4 \u00b5M), the significant changes were detected by N-14, F-14 alkaloids, and there was no change by the negative inotropic effect of F-24 alkaloid. The results show that the negative inotropic effect of N-14 and F-14 alkaloids on the inhibition of inactivity is directly related to the modulation of AC activity.<\/p>\n<p>Further, in order to clarify the mechanism of negative inotropic action, inotropic effects of the studied alkaloids were investigated in the incubation condition of phorbol 12-myristate-13 acetate (FMA), PKC activator. In the experiments, the heartbeat of the FMA concentration (0,01-1 \u00b5M) had a negative effect on papillary muscle contraction and its <em>IC<\/em><sub>50<\/sub> value equaled 0,1 \u03bcM. The negative inotropic effects of F-24 (<em>IC<\/em><sub>50<\/sub>), F-14 (<em>IC<\/em><sub>50<\/sub>) and N-14 (<em>IC<\/em><sub>50<\/sub>) in the FMA (<em>EC<\/em><sub>50<\/sub>=0.1 \u00b5\u041c) incubation conditions compiled 30.7\u00b16.4%, 21.4\u00b13.5% and 14.6\u00b14.2%, respectively (Fig. 6).<\/p>\n<table style=\"width: 70%;\" border=\"1\" cellpadding=\"5\">\n<tbody>\n<tr>\n<td><img decoding=\"async\" class=\"alignnone size-thumbnail wp-image-31113\" src=\"https:\/\/biomedpharmajournal.org\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig6-150x150.jpg\" alt=\"Figure 6: The inotropic action of isoquinoline alkaloids (N-14, F-14, F-24) in incubation conditions of PKC activator - phorbol 12-myristate-13-acetate (PMA) (IC50=0, 1 \u00b5M).\" width=\"150\" height=\"150\" srcset=\"https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig6-150x150.jpg 150w, https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig6-256x256.jpg 256w, https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig6.jpg 636w\" sizes=\"(max-width: 150px) 100vw, 150px\" \/><\/td>\n<td><strong>Figure <\/strong><strong>6<\/strong><strong>: The inotropic action of isoquinoline alkaloids (N-14, F-14, F-24)<\/strong><\/p>\n<p><a href=\"http:\/\/biomedpharmajournal.org\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig6.jpg\" target=\"_blank\">Click here to View Figure<\/a><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The ordinate axis shows the pulsating force of the papillary muscle, expressed as a percentage of the maximum value of 100%. The stimulation frequency is 0.5 Hz (t=36\u00b10.5\u00baC). *\u2013 for control ** \u2013 <em>\u0440<\/em>&lt;0,01 (<em>n<\/em>=4\u20135).<\/p>\n<p>Based on these results, it is suggested that the effects of negligible inotropic effects of the studied isoquinoline alkaloids were partially related to the change of [\u0421\u0430<sup>2+<\/sup>]<em><sub>in<\/sub><\/em> concentration by modulating PKC activity.<\/p>\n<p><strong>E<\/strong><strong>ffect<\/strong><strong>s<\/strong><strong> of Isoquinoline Alkaloids on RyR2 Activity<\/strong><\/p>\n<p>In the series of subsequent experiments, we have studied the effects of isoquinoline alkaloids (N-14, F-14) on possible RyR2 activity. Methods, including RyR2 activator \u2013 caffeine (20 mM) in case of non-stimulus incidence of single contraction, allows us to estimate the amount of [\u0421\u0430<sup>2+<\/sup>]<em><sub>SR<\/sub><\/em><sup>24<\/sup>. Under these conditions, no post-rest potentiation is observed for about 30 seconds after 15 minutes, which is explained due to caffeine (20 mM) [Ca<sup>2+<\/sup>]<sub>SR<\/sub> excretion into cytosol completely [Bouchard, 1990]. In this case, caffeine (20 mM) causes a single contraction due to Ca<sup>2+<\/sup> excretion from SR through RyR2 in non-stimulating conditions.<\/p>\n<p>The concentration increase of [Ca<sup>2+<\/sup>]<sub>in<\/sub> formed by the action of caffeine (20 mM) is normalized by the Na<sup>+<\/sup>\/Ca<sup>2+<\/sup> exchange function<sup>25<\/sup>. In incubation condition when [Na<sup>+<\/sup>]<sub>out<\/sub>=0, Na<sup>+<\/sup>\/Ca<sup>2+<\/sup> exchanger exporting function is blocked, and subsequently [Ca<sup>2+<\/sup>]<sub>in<\/sub> ions concentration and amplitude force of contraction are maintained in a stable state under caffeine (20 \u03bcM) <sup>26<\/sup>.<\/p>\n<p>In our experiments when [Na<sup>+<\/sup>]<em><sub>out<\/sub><\/em>=0, caffeine (20 mM), without stimulus, was found to increase papillary muscle force contraction by 28\u00b14.4%, compared to control. The amplitude force contraction of the papillary muscle, generated by caffeine (20 mM) in the presence of F-14 (40 \u03bcM) and N-14 (30 \u03bcM) isoquinoline alkaloids in the incubation environment, decreased for 18\u00b13.7% and 35.6\u00b14.1%, in comparison with the control group, respectively (Figure 7).<\/p>\n<table style=\"width: 70%;\" border=\"1\" cellpadding=\"5\">\n<tbody>\n<tr>\n<td><img decoding=\"async\" class=\"alignnone size-thumbnail wp-image-31114\" src=\"https:\/\/biomedpharmajournal.org\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig7-150x150.jpg\" alt=\"Figure 7. Inotropic effect of isoquinoline alkaloids (F-14 and N-14) in incubation conditions of caffeine (20 mM).\" width=\"150\" height=\"150\" srcset=\"https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig7-150x150.jpg 150w, https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig7-256x256.jpg 256w, https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig7.jpg 562w\" sizes=\"(max-width: 150px) 100vw, 150px\" \/><\/td>\n<td><strong>Figure 7. <\/strong><strong>I<\/strong><strong>notropic <\/strong><strong>effect<\/strong><strong> of isoquinoline alkaloids (F-14<\/strong><strong> and<\/strong><strong> N-14) <\/strong><\/p>\n<p><a href=\"http:\/\/biomedpharmajournal.org\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig7.jpg\" target=\"_blank\">Click here to View Figure<\/a><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The ordinate axis shows force contraction of the papillary muscle, expressed as a percentage of the maximum value of 100%. The stimulation frequency is 0.5 Hz (t=36\u00b10.5\u00baC). * \u2013 for control ** \u2013 <em>\u0440<\/em>&lt;0.01 (<em>n<\/em>=3\u20135).<\/p>\n<p>The results show, that the concentrations of \u0421\u0430<sup>2+<\/sup> ions in SR under the influence of F-14 and N-14 isoquinoline alkaloids are negatively affected. The experiments also revealed, that in F-24 isoquinoline alkaloid (60 \u00b5M) incubation condition, single-contraction changes into tonic contraction and its amplitude remains constant by caffeine (20 mM) (Fig. 8).<\/p>\n<table style=\"width: 70%;\" border=\"1\" cellpadding=\"5\">\n<tbody>\n<tr>\n<td><img decoding=\"async\" class=\"alignnone size-thumbnail wp-image-31115\" src=\"https:\/\/biomedpharmajournal.org\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig8-150x150.jpg\" alt=\"Figure 8: Inotropic action of caffeine (20 mM) on papillary muscle contraction in the presence of F-24 (60 \u03bcM) alkaloid in the incubation environment (original image).\" width=\"150\" height=\"150\" srcset=\"https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig8-150x150.jpg 150w, https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig8-256x256.jpg 256w, https:\/\/biomedpharmajournal.org\/staging\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig8.jpg 622w\" sizes=\"(max-width: 150px) 100vw, 150px\" \/><\/td>\n<td><strong>Figure<\/strong><strong> 8<\/strong><strong>:<\/strong><strong> Inotropic action of caffeine (20 mM) on papillary\u00a0<\/strong><\/p>\n<p><a href=\"http:\/\/biomedpharmajournal.org\/wp-content\/uploads\/2020\/03\/Vol13No1_Com_ino_Fig8.jpg\" target=\"_blank\">Click here to View Figure<\/a><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The time caffeine (20 mM) added to the medium containing F-24 (60 \u00b5M) was indicated with a pointer. The frequency of Initial Stimulation is 1 Hz.<strong>\u00a0<\/strong><\/p>\n<p>This can be explained with the increase of [Ca<sup>2+<\/sup>]<em><sub>in<\/sub><\/em> concentration through Na<sup>+<\/sup>\/Ca<sup>2+<\/sup> exchanger blockade together with the modulation of RyR2 under the influence of F-24, and constancy of [Ca<sup>2+<\/sup>]<em><sub>in <\/sub><\/em>concentration and the contraction force amplitude with caffeine (20 mM)<sup>27<\/sup>.<strong>\u00a0<\/strong><\/p>\n<p><strong>Conclusion<\/strong><\/p>\n<p>Thus, the negative inotropic effect of N-14, F-14 and F-24 isoquinoline alkaloids on the papillary muscle contraction were established to be in association with partial blockade of Ca<sup>2+<\/sup><sub>L<\/sub>-channel in cardiomyocytes. It has been determined that negative inotropic effect of N-14, F-14 alkaloids occur depending on PKC modulation. The negative inotropic effect of F-24 isoquinoline alkaloid was suggested to arise from Na<sup>+<\/sup>\/Ca<sup>2+<\/sup> exchanger blockade together with RyR2 modulation.<\/p>\n<p><strong>\u00a0<\/strong><strong>Conflict of Interest<\/strong><\/p>\n<p>The authors have declared that no conflict of interest exists.<\/p>\n<p><strong>Acknowledgements<\/strong><\/p>\n<p>This work was supported by a grant FA-F6-T083 from the Coordinating Committee for Development of Science and Technology under the Cabinet of Ministers of the Republic of Uzbekistan.<\/p>\n<p><strong>References<\/strong><\/p>\n<ol>\n<li>Heart disease and stroke statistics \u2013 2017 update: A report from the American heart association. http:\/\/circ. ahajournals.org\/content\/135\/10\/e146 Date of the application: 15.08.2017.<\/li>\n<li>Nichols, N.Townsend, P.Scarborough, M.Rayner. Cardiovascular disease in Europe 2014: Epidemiological update. 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V 5(59). \u2013 P. 5\u20138.<\/li>\n<\/ol>\n<p><strong>Abbreviations Used in This Paper <\/strong><strong>are as Follows<\/strong><\/p>\n<ol>\n<li>AC = Adenylate cyclase;<\/li>\n<li>ATP = Adenosintriphosphat;<\/li>\n<li>\u0421\u0430<sup>2+<\/sup><sub>L<\/sub>-channels = The L-type Ca<sup>2+<\/sup>\u2013channels;<\/li>\n<li>[cAMP]<sub>in <\/sub>= The <em>intracellular concentration<\/em> of <em>Cyclic Adenosine <\/em>3&#8242;,5&#8217;\u2013<em>monophosphate<\/em><em>;<\/em><\/li>\n<li>[\u0421\u0430<sup>2+<\/sup>]<sub>in<\/sub> = The <em>intracellular concentration<\/em> of Ca<sup>2+<\/sup> <em>ions;<\/em><\/li>\n<li><em>+ dF\/dt<sub>max<\/sub><\/em> = The maximum velocity of force development;<\/li>\n<li><em>\u2013<\/em><em>dF\/dt<sub>max<\/sub><\/em> = The maximum velocity of relaxation;<\/li>\n<li>EC<sub>50 <\/sub>= The values of concentration for 50% of the maximal effect;<\/li>\n<li>Gs = Guanine nucleotide-binding proteins;<\/li>\n<li>HSE = Hugo Sachs Elektronik;<\/li>\n<li>PKA = Protein kinase A;<\/li>\n<li>SR = Sarcoplasmic reticulum;<\/li>\n<li>RyRs = Ryanodine Receptors or Sarcoplasmic reticulum Ca<sup>2+<\/sup>\u2013channels;<\/li>\n<li>CICR = &#8220;Ca<sup>2+<\/sup> induced Ca<sup>2+<\/sup> release&#8221;;<\/li>\n<li>SERCA = \u0421\u0430<sup>2+<\/sup>\u2013ATPasa of sarcoplasmic reticulum;<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"<p>Introduction In the world, there has been a trend towards  [&#8230;]<\/p>\n","protected":false},"author":13,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[75],"tags":[],"class_list":["post-31106","post","type-post","status-publish","format-standard","hentry","category-vol13no1"],"_links":{"self":[{"href":"https:\/\/biomedpharmajournal.org\/staging\/wp-json\/wp\/v2\/posts\/31106","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/biomedpharmajournal.org\/staging\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/biomedpharmajournal.org\/staging\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/biomedpharmajournal.org\/staging\/wp-json\/wp\/v2\/users\/13"}],"replies":[{"embeddable":true,"href":"https:\/\/biomedpharmajournal.org\/staging\/wp-json\/wp\/v2\/comments?post=31106"}],"version-history":[{"count":6,"href":"https:\/\/biomedpharmajournal.org\/staging\/wp-json\/wp\/v2\/posts\/31106\/revisions"}],"predecessor-version":[{"id":40344,"href":"https:\/\/biomedpharmajournal.org\/staging\/wp-json\/wp\/v2\/posts\/31106\/revisions\/40344"}],"wp:attachment":[{"href":"https:\/\/biomedpharmajournal.org\/staging\/wp-json\/wp\/v2\/media?parent=31106"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/biomedpharmajournal.org\/staging\/wp-json\/wp\/v2\/categories?post=31106"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/biomedpharmajournal.org\/staging\/wp-json\/wp\/v2\/tags?post=31106"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}