Julie Gardener
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Reduttion by A9- tetrahydrocannabinol in the blood pressure of
hypertensive rats bearing regenerated adrenal glands
M. K. BIRMINGHAMhypertensive rats bearing regenerated adrenal glands
Allan Memorial Institute of Psychiatry,
McGill University, Montreal, Quebec,
Canada
Br J Pharmacol. 1973 May; 48(1): 169–171.
Abstract
A suspension of (-)-A9-trans-tetrahydrocannabinol (A9-THC) (3 mg/kg body wt) was administered daily for one week by i.p. injection to female rats showing the syndrome of adrenal regeneration hypertension (ARH). Other ARH rats received no injections or injections of vehicle only. On the first day,A9-THC decreased the average blood pressure by 38±6 mmHg 1 h, 31+5 mmHg 3 h, and 11 ±5 mmHg 5 h after injection (n-=0). On subsequent days the acute effect disappeared, but statistically highly significant decreases were observed between the blood pressures of the A9-THC-treated group and those of the other two groups. Plasma corticosterone concentrations, measured on the eighth day of treatment, one hour after injection time, averaged 26-1 ±2-7 ,ug/100 ml in the untreated animals, 26-6±2'0 gg/100 ml in the vehicle-injected animnals, and 21-3±2-4 jug/100 ml in the animals injected with A9-THC. The findings indicate that A9 THC, at a moderate dose for the rat, is capable of lowering the blood pressure in rats suffering from adrenal regeneration hypertension and that chronic administration of A'-THC does not appear to stimulate the pituitary-adrenal axis, in contrast to reported effects of acute administration (Barry, Perhach & Kubena, 1970).
The pharmacological effects of marihuana and its main active principle, (-) A9-transtetrahydrocannabinol (AL9-THC), have been summarized in several recent reviews (Neumeyer & Shagoury, 1971; Gershon, 1970; Hollister, 1971). Investigations on blood pressure have largely been confined to normotensive subjects. Isbell, Gorodetzsky, Jasiniski, Claussen, Von Spulak & Korte (1967) noted no significant changes upon administration of A9-THC to human volunteers, but a reduction of blood pressure has been observed in rats (Ho, An, Fritchie, Englert & Mclsaac, 1971), dogs (Garriott, Forney, Hughes & Richards, 1968) and cats (Dagirmanjian & Boyd, 1962) after synthetic tetrahydrocannabinol derivatives. Spontaneously hypertensive rats with an average blood pressure in excess of 200 mmHg, responded to a crude alcoholic extract of marihuana, administered intraperitoneally, by a highly significant, acute reduction in blood pressure to normotensive levels (Birmingham, Oliver, Possanza, Langlois & Stewart, 1972).
The present work deals with effects of A9-THC on the blood pressure of rats suffering from adrenal regeneration hypertension.
Source: Reduttion by
