ABSTRACT
In man the single acute dose usually has little or no effect on the blood pressure; it may cause a slight rise. The cardiovascular system works under the influence of a tightly balanced control by the autonomic nerves, which varies somewhat from one species to another, and is affected by a considerable number of drugs including not merely the obvious blockers but the centrally acting drugs and anesthetics. In anesthetized animals intravenous injection of cannabis or of ?9-tetrahydrocannabinol causes a fall in blood pressure which may persist for an hour or two. The loss of peripheral arterial tone, presumed to be a consequence of sympathetic inhibition, may come first and the tachycardia is a consequential baroreceptor reflex, or at least that is one suggestion. Unitary explanations of mechanisms of action are logically preferable to disconnected multiple causes; herein may lay the key to progress in cannabinoid therapy for hypertension.
