[Effect of neuroactive aminoacids on central mechanisms of vascular regulation]

In cats and rats, GABA and glycine depressed pressor vasomotor reactions and responses of sympathetic nerves to stimulation of the medial and vestibular nuclei of the bulbar reticular formation. These drugs depressed vasomotor responses to direct stimulation of the spinal lateral horns. GABA reduced the activated bulbo-spinal influences and inhibition of responses of the "spinal" vessels to stimulation of the solitary tract nucleus and paramedian reticular nuclei. GABA (100--200 mg/kg) depressed vasomotor responses to mechanoreceptor stimulation and increased the responses to chemoreceptor stimulation while glycine did not change them. GABA and glycine exerted no adrenolytic or myotropic effects. GABA did not affect identically the transmission in different sympathetic ganglions. Glycine did not alter the ganglionic transmission. The site and mode of the neuroactive aminoacids effect on the central mechanisms for vasomotor regulation are discussed.