Blood pressure and hypothalamic NA-GABA interaction in spontaneously hypertensive rats (SHR): effect of...

The effect of DSP-4 [N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine] on the content of catecholamines (NA and DA) and gamma-aminobutyric acid (GABA) in the hypothalamus and on the blood pressure were studied in rats. Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR) were injected with DSP-4 (50 mg/kg i.p. twice) and tested for 15 days thereafter. Fifteen days after DSP-4 lesioning, a significant reduction of NA levels without changes in DA and GABA concentration in the hypothalamus of both strains was found. However the blood pressure appeared unaffected by the DSP-4 pretreatment in WKY and SHR rats. In line with previous data the amounts of catecholamines and GABA in the hypothalamus were significantly lower in SHR control animals than in WKY control rats. The results suggest that NA/GABA interaction in the hypothalamus do not play an important role in blood pressure regulation. It may be further supposed that the local NA transmission does not play an important role in the phenomenon discussed. Moreover, a contribution of hypothalamic GABA and DA to the control of blood pressure is confirmed.