AJP - Regulatory, Integrative and Comparative Physiology, Vol 252, Issue 3 594-R598, Copyright © 1987 by American Physiological Society
Acute central effects of L-glutamate in pentobarbital-anesthetized dogs
J. E. Chelly, M. F. Doursout and J. P. Buckley
Microinjections of L-glutamate (10(-10) to 2 X 10(-8) mol/kg) into the
nucleus of tractus solitarii produced a dose-dependent increase in mean
arterial pressure and a decrease in heart rate. L-Glutamate-induced
hypertension was prevented by spinal transection and pretreatment with
atropine (1 mg/kg iv) reversed the bradycardia. L-Glutamate also produced a
dose-dependent increase in mean arterial pressure when injected
intravenously and into the cisterna magna, but the dose-effect curves were
shifted to the right. Finally, pretreatment with hexamethonium (30 mg/kg
iv) abolished the hypertension resulting from intravenous injections of
L-glutamate. These data demonstrate that the nucleus of tractus solitarii
may play a determinant role in the central pressor effects of L-glutamate.
In addition, we demonstrated that this hypertension was due to a central
sympathetic stimulation and that the autonomic nervous system also mediated
the pressor effects of intravenous L-glutamate.
