[Comparison of the effects of betablockers and captopril on the development of genetic hypertension in the rat].

The preventative effects of betablockers and captopril on the development of genetic hypertension in genetically hypertensive rats, were studied after long-term daily dosage by forced feeding, from the 5th to the 20th week of age of the animals. Of the drugs studied, captopril, atenolol and propranolol limited the development significantly, but pindolol only had a modest effect and acebutolol was ineffective. No correlation was found between the degree of prevention of genetic hypertension and the intensity of betablockade. Atenolol and propranolol prevent genetic hypertension by I) reducing cardiac output, a reduction which is not neutralised by the simultaneous change in peripheral resistance, 2) decreasing plasma renin concentrations, and 3) limiting the development of myocardial hypertrophy. Captopril is very effective in preventing the development of genetic hypertension and acts: 1) by causing an early and lasting fall in peripheral resistance related to the suppression of Angiotensin II, and possibly by potentialising the vasodilatation of bradykinins and, 2) by limiting myocardial hypertrophy.