Central serotonergic agents raise the repetitive extrasystole threshold of the vulnerable period of the canine ventricular myocardium.
نویسندگان
چکیده
Systemic administration of three central serotonergic agents, melatonin, 5-methoxytryptophol, and 6-chloro-2-(1-piperazinyl)-pyrazine (MK-212), produced significant increases in the threshold of the vulnerable period for repetitive electrical activity in the canine cardiac ventricle. MK-212 was effective despite bilateral vagotomy. The specific serotonin antagonist, metergoline, blocked the effect of MK-212 on the threshold. An increase in central serotonergic activity may inhibit the flow of arrhythmogenic sympathetic nerve traffic from the brain to the heart.
منابع مشابه
Influence of glucose, insulin, and potassium on vulnerability to ventricular fibrillation in the canine heart.
We studied the influence of glucose (G), insulin (I) and potassium (K) on vulnerability to ventricular fibrillation (VF) of the nonischemic canine myocardium. Vulnerability was assessed by determining VF and repetitive extrasystole (RE) thresholds with a single stimulus applied to the right ventricular endocardium during the vulnerable period. Electrical testing of the heart was performed befor...
متن کاملMuscarinic effects of vagosympathetic trunk stimulation on the repetitive extrasystole (RE) threshold.
The precise mechanism of the vagus in opposing adrenergic influences on cardiac vulnerability has not been defined. In the present investigation, cholinergic stimulation was produced by administering the selective muscarinic agent methacholine (MCh) and ventricular vulnerability was assessed by measuring the repetitive extrasystole (RE) threshold. MCh produced a sustained 98 +/- 12% (P less tha...
متن کاملHYPOVENTILATION PRIOR TO ISCHEMIA PRECONDITIONS RAT MYOCARDIUM
Repetitive episodes of brief regional ischemia have been shown to reduce the severity of life-threatening ventricular anhythrnias and infarct size that occur during prolonged occlusion of the coronary artery. This phenomenon is known as ischemic preconditioning. During studies in anesthetized, open chest Wistar rats, we accidentally observed that poorly ventilated animals had a reduced seve...
متن کاملEvaluation of the force-frequency relationship as a descriptor of the inotropic state of canine left ventricular myocardium.
The short-term force-frequency characteristics of canine left ventricular myocardium were examined in both isolated and intact preparations by briefly pertubing the frequency of contraction with early extrasystoles. The maximum rate of rise of isometric tension (Fmas) of the isolated trabeculae carneae was potentiated by the introduction of extrasystoles. The ratio of Fmas of potentiated to con...
متن کاملComparison of the defibrillation threshold and the upper limit of ventricular vulnerability.
To examine the relationship between the defibrillation threshold and the strength of shocks that induce ventricular fibrillation during the vulnerable period, we determined the defibrillation threshold in 22 open-chest dogs using epicardial defibrillation electrodes with the cathode at the ventricular apex and the anode at the right atrium. We also determined whether there was an upper limit of...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Circulation research
دوره 44 5 شماره
صفحات -
تاریخ انتشار 1979