Neuropeptide Y is a prejunctional inhibitor of vagal but not sympathetic inotropic responses in guinea-pig isolated left atria
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چکیده
منابع مشابه
Selective reserpine-induced supersensitivity of the positive inotropic and chronotropic responses to isoprenaline and salbutamol in guinea-pig isolated atria.
1 Dose-response curves for the positive inotropic and chronotropic responses to isoprenaline were obtained in atria from untreated guinea-pigs and those receiving various reserpine pretreatments. 2 Tension responses were unaffected, whereas rate responses were depressed by the lowest dose of reserpine (0.05 mg/kg i.p. at 24 hours). 3 With larger 24 h doses and a 3 day pretreatment, the rate and...
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Sodium valproate (SV), an antiepileptic drug has several mechanism of action. It inhibits voltage sensitive Na+ channels and reduces intracellular Na accumulation. These actions are similar to that of both phenytoin and carbamazepine. We have investigated the direct cardiac action of SV and its effects on ouabain-induced arrhythmia in isolated guinea-pig atria. The guinea-pig atrium was dissect...
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UNLABELLED The aim of this paper was to investigate the effects of pinacidil and diazoxide, the activators of sarcolemmal and mitochondrial ATP-sensitive K(+) channels (K(ATP)), respectively, on heart rate and force of contraction in female and male guinea pigs. Experiments were performed on the isolated, spontaneously beating, right atria obtained from guinea pigs of both genders. First series...
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Although the positive inotropic effect of cardiac glycosides correlates well with inhibition of Na+ pump activity in many preparations, digitalis at low concentrations (10(-9) to 10(-8) M) may produce an apparent stimulation of monovalent cation transport in isolated intact myocardium or produce an inotropic effect that does not correlate with pump inhibition. Digitalis is known to modify tissu...
متن کاملEffects of neuropeptide Y on cell length and membrane currents in isolated guinea pig ventricular myocytes.
Direct effects of neuropeptide Y were studied in left ventricular myocytes isolated from guinea pigs. Contraction was measured as the change in unloaded cell length using a photodiode array. Action potentials were elicited at 1 Hz in current-clamp mode, and membrane currents were measured using a switch-clamp amplifier with 2 M-KCl microelectrodes. At concentrations of 10(-6) M and above, neuro...
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ژورنال
عنوان ژورنال: British Journal of Pharmacology
سال: 1999
ISSN: 0007-1188,1476-5381
DOI: 10.1038/sj.bjp.0702565