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Effect of sinusoidal stretch on reactivity of the rat arteries
THE NONLINEAR OSCILLATION MECHANISM OF AN AlJTONOMOUS PARASYMPATHETIC ACTIVITY IN ISCHEMIC HEART DISEASE V Borisov. A Matusova, L Mudrova, A Reyman Sttrtr ,WU’I& .4caa’entyVNtzltt!l; No~~gorod, Kt~.vs~tr An analysis of statistic characteristics of heart rate variability m 240 acute phase myocardial infarction (Ml) patients has showed a possibility of the nonlinear oscillating mechanism m a parasympathetic activity There are possible biosystems covered by this mechanism a) stable system, keeping a but posessing diminished adaptivity working activity. (available in uncomplicated MI group), b) adaptive (low active) system, having a small stability (available in a severe haemodynamic disturbance Ml group), c) system similar to the previous one but having continuous transition process from (a) to (b) that leads to the appearance of self-oscillation (found in Ml group with an electric myocardial instability) The similar behaviour was also found for healthy persons and patients with non-acute form of ischemic heart disease These results are used in design of hard- and software parts of heart monitoring systems
EFFECT OF SlNUSOlDAL STRETCH ON REACTIVITY OF THE RAT ARTERIES D. P Dvoretsky, V N Yartsev, 0 V Karatchentseva, M P Granstrem, and G V Chernyavskaya Laboratory of C‘trctrlattott, Pavlov Ittstrtttte of t’hystology, St.Petershttrg, Ktrssra. The effect of sinusoidal stretch of the rat tail and mesenteric artery segments on their reactivity at different level of resting tension was studied The segments, mounted on a miograph, were stretched by computercontrolled motorized micromanipulator Dynamic stretch (1, 5 or 7 Hz) inhibited artery constriction, induced by noradrenaline (1 0m5M) or electrical field stimulation (EFS) of intramural nerves irrespective of the stretch frequency used. The effect was more pronounced at the resting tension, corresponding to the low level of blood pressure In contrast, dynamic stretch enhanced the segment dilation, induced by EFS of noradrenaline-contracted (10.’ M) arteries Maximal increase of the dilation (24 525 0 % in mesenteric and 50 3515 6 % in the tail artery) was observed at dynamic stretch frequency 5 Hz The decrease of the constrictor and increase of dilator response to EFS was proportional to the amplitude of the dynamic stretch An inhibitor of nitric oxide synthesis, No-nitro-L-arginine (1O-4 M), abolished the difference in segment reactivity under static in comparison with dynamic stretch conditions The results indicate that dynamic stretch of the arteries activate nitric oxide synthesis/secretion thus inducing decrease of constrictor and increase of dilator response to stimuli indicated
PREVENTION OF THE CARDIOTROPIC ACTION OF LEAD BY PHOSPOLIPASE INHIBITOR A. T. Kismuratova Chair ofPuthophysiologv, Kuzakh State Medical Universi&. Almaty, Kazakhstan The aim of the present report is study of protecting effect of quercetini (“Uzkhimfarm”. Uzbekistan). the inhibitor of membrane phospholipase activity during lead cardiotoxity. The experiments were carried out with adult white rats. The heartbeat function of the isolated organ was studied (Fallen E. e.a.. 1967) in one hour and 7 days after lead acetate (LA) administer in single dosage 100 mg/kg. Experimental animals were treated by quercetini (35 mg/rg) three days before the LA injection and then till general experiment. It was shown that the expressed heartbeat depression after LA injection occurred on 43.7 % and 53.2 % in one hour and 7 days accordingly. When heartbeat high frequencies (3-8 Hz) forced the animals treated by LA had negative inotropic effect as compared with control. Preliminary quercetini administer to experimental animals completely prevented the heartbeat disorder. The frequency test identified the increase of heart reactivity to load: in one hour after LA injection the negative initropic effect wasn’t occur and in 7 days the positi] e inotropism was noticed.
SIGNAL TRANSDUCTION PATHWAYS IN CULTURED VASCULAR SMOOTH MUSCLE CELL PROLIFERATION INDUCED BY LYSOPHOSPHATIDIC ACID N. K. Liu, C. S. Tang, X. Li, Y. S. Gong, J. Y. Su Institute of Cardiovascular Research, Beijing Medical University, Beijing 100083 P. R. China Lysophosphatidic acid (LPA) is an intercellular phospholipid messenger with a wide range of biological activities. In the present study, we investigated the signal transduction pathways in vascular smooth muscle cell (VSMC) proliferation induced by LPA. The 3H-TdR incorporation and mitogen-activated protein kinase (MAPK) activity were measured in cultured VSMC. The results showed that LPA enhanced 3H-TdR incorporation of cultured VSMC in a concentration-dependent manner, and increased MAPK activity concurrently. The relationship between 3H-TdR incorporation and MAPK activity induced by LPA showed significant positive correlation (r=O.84, PcO.01). PQ09s059, H7, PMA and Pertussis Toxin (PTX) inhibited the stimulation of VSMC 3H-TdR incorporation and MAPK activity by LPA. In conclusion, LPA has a stimulating effect on VSMC proliferation; The LPA-induced VSMC proliferation may be related to the signal transduction pathway of G protein sensitive to PTX, which is mediated by protein kinase C and MAPK .
EFFECT OF SlNUSOlDAL STRETCH ON REACTIVITY OF THE RAT ARTERIES D. P Dvoretsky, V N Yartsev, 0 V Karatchentseva, M P Granstrem, and G V Chernyavskaya Laboratory of C‘trctrlattott, Pavlov Ittstrtttte of t’hystology, St.Petershttrg, Ktrssra. The effect of sinusoidal stretch of the rat tail and mesenteric artery segments on their reactivity at different level of resting tension was studied The segments, mounted on a miograph, were stretched by computercontrolled motorized micromanipulator Dynamic stretch (1, 5 or 7 Hz) inhibited artery constriction, induced by noradrenaline (1 0m5M) or electrical field stimulation (EFS) of intramural nerves irrespective of the stretch frequency used. The effect was more pronounced at the resting tension, corresponding to the low level of blood pressure In contrast, dynamic stretch enhanced the segment dilation, induced by EFS of noradrenaline-contracted (10.’ M) arteries Maximal increase of the dilation (24 525 0 % in mesenteric and 50 3515 6 % in the tail artery) was observed at dynamic stretch frequency 5 Hz The decrease of the constrictor and increase of dilator response to EFS was proportional to the amplitude of the dynamic stretch An inhibitor of nitric oxide synthesis, No-nitro-L-arginine (1O-4 M), abolished the difference in segment reactivity under static in comparison with dynamic stretch conditions The results indicate that dynamic stretch of the arteries activate nitric oxide synthesis/secretion thus inducing decrease of constrictor and increase of dilator response to stimuli indicated
PREVENTION OF THE CARDIOTROPIC ACTION OF LEAD BY PHOSPOLIPASE INHIBITOR A. T. Kismuratova Chair ofPuthophysiologv, Kuzakh State Medical Universi&. Almaty, Kazakhstan The aim of the present report is study of protecting effect of quercetini (“Uzkhimfarm”. Uzbekistan). the inhibitor of membrane phospholipase activity during lead cardiotoxity. The experiments were carried out with adult white rats. The heartbeat function of the isolated organ was studied (Fallen E. e.a.. 1967) in one hour and 7 days after lead acetate (LA) administer in single dosage 100 mg/kg. Experimental animals were treated by quercetini (35 mg/rg) three days before the LA injection and then till general experiment. It was shown that the expressed heartbeat depression after LA injection occurred on 43.7 % and 53.2 % in one hour and 7 days accordingly. When heartbeat high frequencies (3-8 Hz) forced the animals treated by LA had negative inotropic effect as compared with control. Preliminary quercetini administer to experimental animals completely prevented the heartbeat disorder. The frequency test identified the increase of heart reactivity to load: in one hour after LA injection the negative initropic effect wasn’t occur and in 7 days the positi] e inotropism was noticed.
SIGNAL TRANSDUCTION PATHWAYS IN CULTURED VASCULAR SMOOTH MUSCLE CELL PROLIFERATION INDUCED BY LYSOPHOSPHATIDIC ACID N. K. Liu, C. S. Tang, X. Li, Y. S. Gong, J. Y. Su Institute of Cardiovascular Research, Beijing Medical University, Beijing 100083 P. R. China Lysophosphatidic acid (LPA) is an intercellular phospholipid messenger with a wide range of biological activities. In the present study, we investigated the signal transduction pathways in vascular smooth muscle cell (VSMC) proliferation induced by LPA. The 3H-TdR incorporation and mitogen-activated protein kinase (MAPK) activity were measured in cultured VSMC. The results showed that LPA enhanced 3H-TdR incorporation of cultured VSMC in a concentration-dependent manner, and increased MAPK activity concurrently. The relationship between 3H-TdR incorporation and MAPK activity induced by LPA showed significant positive correlation (r=O.84, PcO.01). PQ09s059, H7, PMA and Pertussis Toxin (PTX) inhibited the stimulation of VSMC 3H-TdR incorporation and MAPK activity by LPA. In conclusion, LPA has a stimulating effect on VSMC proliferation; The LPA-induced VSMC proliferation may be related to the signal transduction pathway of G protein sensitive to PTX, which is mediated by protein kinase C and MAPK .