Parasympathetic cardiac effects in sympathectomized rats.

In adult sympathectomized rats the right and left vagus nerves exhibited asymmetric effects on heart rate and strength of cardiac contractions. After vagotomy, the heart rate and stroke volume remained high in sympathectomized rats, but returned to normal in intact animals. The sympathetic nervous system plays a role in postvagotomic tachycardia. Sympathectomized rats were characterized by higher reactivity of cardiac beta-adrenoceptors to propranolol compared to intact animals.