ABSTRACT
The amino acid γ-aminobutyric acid (GABA) is synthesized by enzymatic decarboxylation from glutamic acid and is considered to be the principle inhibitory neurotransmitter in the brain. There is considerable evidence in favour of a role of GABA in blood pressure regulation and, in addition, there are indications that GABA is involved in the development of hypertension. This chapter reviews four main aspects of GABAergic involvement in cardiovascular regulation: the effect of intracerebroventricular injections of GABAergic drugs; hypothalamic GABAergic mechanisms; GABAergic mechanisms in the medulla; and alterations in central GABAergic activity in hypertension. Evidence for a role of central GABA in the development of hypertension has been obtained mostly in spontaneously hypertensive rats (SHR) and, to a lesser extent, in rats with hypertension caused by treatment with deoxycorticosterone acetate and salt. Micro-injection of the GABA synthesis inhibitor, 3-mercaptopropionic acid, caused an increase in blood pressure in young SHR and in young and adult wistar-Kyoto rats, but not in adult SHR.
