Effects of systemic ethanol on medullary vasomotor neurons and baroreflexes.

The acute effects of systemic ethanol on reticulospinal sympathoexcitatory neurons were examined in vivo in anesthetized, paralyzed rats. Ethanol (0.45 g/kg, i.v.) potentiated the depressant effect of locally applied gamma-aminobutyric acid (GABA) but attenuated the excitatory effect of L-glutamate. The baroreflex-mediated inhibition of these neurons and sympathetic nerve activity were partially depressed by the agent while aortic nerve activity and its sensitivity to changes in arterial pressure were not altered. These results suggest that systemic ethanol may markedly influence cardiovascular function by interfering in medullary GABAergic and glutamatergic transmissions involved in central control of the cardiovascular system.