[Gaba-ergic mechanisms of regulation of the vascular tone and cardiac activity localized in the caudal ventrolateral area of the cat medulla].

Data showing that GABA (0.5-50 mumols) injections into the neuronal structures of the caudal ventrolateral medulla (CVLM) being followed with hypertensive reactions induced by enhancement of the background activities of the renal and inferior cardiac nerves are obtained in acute experiments on cats. Inhibitory cardiac influences from the CVLM are realized in asymmetric manner: neuronal structures from the left side influence the myocardial contractile activity but fail to induce the heart rate changes, while those of the right side preferentially control the heart rate. Bicuculline injections into the CVLM induce an abrupt fall in the arterial pressure level, attenuate the background activities in the peripheral sympathetic nerves, reduce the heart rate and myocardial contractile activity. These data evidence that in cats there is a tonically active inhibitory GABA-ergic input to depressor neurons within the CVLM.