STUDIES ON THE SPECIFICITY OF THE INHIBITORY ACTION OF N,N‐DIISOPROPYL‐N'‐ISOAMYL‐N'‐DIETHYLAMINOETHYLUREA (P‐286) ON ADRENAL CATECHOLAMINE RELEASE IN THE ANAESTHETIZED RAT

Abstract

b 1. The ability of P‐286 (N,N‐diisopropyl‐N'‐isoamyl‐N'‐diethylaminoethylurea) to reduce selectively the release of catecholamines from the adrenal medulla has been studied in urethane‐anaesthetized rats. 2. Pressor responses to acetylcholine (Ach) and the nicotinic receptor‐agonist 1,4‐dimethylphenylpiperazine (DMPP) in rats treated with atropine, (±)‐propranolol and guanethidine were used as the index of adrenal catecholamine release. 3. The injection of P‐286 (1–10 mg/kg, i.v.) elicited a dose‐dependent bradycardia which was associated with hypotension. P‐286 reduced pressor responses to Ach and DMPP in a dose‐dependent manner with an IC50 of 2.5 mg/kg and, following near complete blocka..