GABAergic mechanism involved in sinoaortic denervation in rats

GABAergic neurotransmission in sinoaortic denervated (SAD) rats with that in sham-operated animals 15 days after operation. In sham-operated rats, glutamic acid decarboxylase (GAD) and 4-amino-butyrate-2-oxoglutarate aminotransferase (GABA-T) activities were higher in dorsal than in ventral regions of pons and medulla oblongata and a higher GAD activity was observed in anterior than in posterior hypothalamus. Fifteen days after SAD, GAD and GABA-T activities were significantly reduced in dorsal pons and in anterior hypothalamus whereas GABA-T activity was increased in ventral medulla oblongata. The results indicate the involvement of GABAergic neurotransmission in the deafferentation of the nucleus tractus solitarii by sinoaortic denervation. GABA hypothalamic inputs could be involved in the baroreflexes.