Effect of salt loading and calcium antagonist on the pressor response to angiotensin infusion in the rat

Elucidation of mechanisms of angiotensin tachyphylaxis will be necessary for explaning the continuous vasocontricting action of angiotensin in the vascular smooth muscle, which might be closely correlated to the high blood pressure in renin-dependent or vasoconstricting hypertension. From the results obtained sodium loading rats showed not only augmented pressor response to angiotensin but also inhibiting the appearance of its tachphylaxis under the infusion of Ca-antagonist dose enough to suppress the response to angiotensin in the rats of water drinking. Speculated mechanisms about this phenomenon has been discussed.