AJP - Regulatory, Integrative and Comparative Physiology, Vol 265, Issue 4 792-R797, Copyright © 1993 by American Physiological Society
Effects of anesthesia on cardiac and renal sympathetic nerve activities and plasma catecholamines
K. Matsukawa, I. Ninomiya and N. Nishiura
Department of Cardiac Physiology, National Cardiovascular Center Research Institute, Osaka, Japan.
The effects of pentobarbital and chloralose on cardiac sympathetic nerve
activity (CSNA), renal sympathetic nerve activity (RSNA), arterial pressure
(AP), and heart rate (HR) were examined using conscious cats. Arterial
blood was sampled intermittently to measure plasma epinephrine.
Pentobarbital (25-30 mg/kg iv) decreased CSNA, RSNA, AP, and HR. The
reduction of CSNA (71 +/- 7%) was larger and lasted longer than that of
RSNA (33 +/- 12%). Chloralose (40-50 mg/kg iv) decreased CSNA 66 +/- 9% and
HR, increased RSNA 127 +/- 122%, and did not affect AP. The baroreflex
relationship between AP and CSNA was examined by increasing AP to 145 mmHg
and decreasing AP to 55 mmHg. Both pentobarbital and chloralose shifted the
AP-CSNA relationship curve downward and blunted the slope of the curve,
indicating that both drugs attenuate tonic and baroreflex cardiac
sympathetic outflow. Pentobarbital and chloralose reduced plasma
epinephrine, suggesting a decrease in adrenal sympathetic nerve activity.
It is concluded that pentobarbital or chloralose affects differentially
sympathetic outflows to different organs such as the heart, kidney, and
adrenal gland.
