Role of the renal nerves in gamma-aminobutyric acid-induced antihypertensive effect in spontaneously hypertensive rats.

The aim of this study was to clarify the role of the renal sympathetic nerves in the gamma-aminobutyric acid (GABA)-induced hypotensive effect in spontaneously hypertensive rats. Male spontaneously hypertensive rats (SHR/Izm) aged 7 weeks were divided into four groups on the basis of diet (containing 0.05% GABA, or GABA-free control diet) and operation (renal sympathetic-denervated or sham-operated) (n = 10, each). Water intake, urine volume and urinary sodium were, or tended to be, slightly higher, while plasma renin activity was significantly lower in the GABA group than the GABA-free control group. GABA inhibited the development of hypertension in sham-operated spontaneously hypertensive rats but not in renal-denervated spontaneously hypertensive rats. Plasma renin activity was significantly higher in sham-operated spontaneously hypertensive rats fed the control diet than in the other three groups. These results suggest that a reduction in the effects induced by the renal nerves may play an important role in the hypotensive effect induced in spontaneously hypertensive rats by chronic dietary administration of GABA.