Central depressor effects of amino acids in conscious normotensive and two-kidney, one-clip renovascular hypertensive rats.
The circulatory effects of intracisternal injections of amino acids were investigated in conscious normotensive control rats (NCR) and in two-kidney, one-clip renovascular hypertensive rats (RHR). Arterial pressure was measured with an indwelling catheter connected to a pressure transducer. Heart rate was counted from the arterial pulse. The intracisternal injection of glycine, gamma-aminobutyric acid (GABA), taurine, serine, alanine, and sarcosine decreased blood pressure by an average of 16-30 mmHg in NCR and by an average of 32-55 mmHg in RHR. Both absolute and percent changes of depressor effects by GABA, taurine, serine, and alanine were larger in RHR than in NCR. All these amino acids also showed similar bradycardiac effects in both NCR and RHR, when compared in absolute values. The percent change of bradycardia induced by taurine and sarcosine was larger in RHR than in NCR. However, the degree of bradycardia by serine was larger in NCR than in RHR. These results suggest that serine, alanine, and sarcosine in addition to glycine, GABA, and taurine, play important roles in blood pressure control in conscious normotensive rats via central neural mechanisms and that the hypertension in renovascular hypertensive rats may involve a central abnormality.
Takemoto
Y
Y
Department of Physiology, Hiroshima University School of Medicine, Japan.
D000596:Amino Acids / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002946:Cisterna Magna / Q000187:drug effects / Q000503:physiopathology*; D006339:Heart Rate / Q000187:drug effects; D006978:Hypertension, Renovascular / Q000503:physiopathology*; D007267:Injections; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains
D000596:Amino Acids