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Biomedical subjects

C L Kaul

Publications and source records attributed to C L Kaul.

At least 73 records · Page 4Linked to original sources

Effect of some antihypertensive drugs and catecholamine depletors on the plasma renin activity in the rat.

The effect of some antihypertensive drugs and catecholamine depletors on the plasma renin activity (PRA) has been investigated in the rat. Diazoxide and CIBA 4416-Go. increased and clonidine decreased the PRA significantly. The increase in PRA following diazoxide was partially blocked by oxprenolol, adrenalectomy and demedullation. Adrenal cortex does not seem to contribute to this increase in PRA following diazoxide. Pretreatment of rats with reserpine, guanethidine or 6-hydroxydopamine alsine, guanethidine and 6-hydroxydopamine when given acutely or repeatedly (for 3 days) did not produce any significant change in PRA. It is concluded that vasodilators like diazoxide and CIBA 4416-Go. increase PRA resulting from sympathetic activation which follows hypotension; this increase is blocked by catecholamine depletors like reserpine, guantethidine and 6-hydroxydopamine.

Animals↗

Importance of the sympathetic nervous system in the development of renal hypertension in the rat.

1. Chemical sympathectomy with 6-hydroxydopamine (6-OHDA) prevented the development of renal hypertension in 80% of weanling male rats of the C.F. strain.2. Adult male rats treated with 6-OHDA developed hypertension on bilateral clamping of the renal arteries.3. Demedullation of the adrenal glands followed by 6-OHDA treatment in adult rats prevented the development of hypertension in 75% of them.4. Weanling rats treated with 6-OHDA did not have any measurable catecholamines in their hearts up to 72-78 days after treatment.5. Unlike the weanling rats, the hearts of adult rats (demedullated or with intact medulla) showed significant refilling (40-50%) of catecholamine stores 60 days after 6-OHDA treatment.6. It is concluded that the functional sympathetic nervous system is important in the development of renal hypertension in the rat.

Adrenal Glands↗

Mechanism of the antagonism of the hypotensive action of guanethidine by propranolol.

1. Propranolol antagonizes the hypotensive effect of guanethidine in renal hypertensive but not in adrenal demedullated renal hypertensive rats.2. Guanethidine does not interfere with the release of catecholamines from the adrenal gland which follows splanchnic nerve stimulation in cats anaesthetized with pentobarbitone.3. Guanethidine does not release or interfere with the release of catecholamines after the intravenous injection of physostigmine in the rat.4. Propranolol antagonizes the antihypertensive effect of guanethidine by potentiating the vasopressor effects of catecholamines released from the adrenal glands during the induction stage of ether anaesthesia.

Adrenal Glands↗