[Influence of changes in the vegetative tonus on the effects of succinylcholine on blood pressure (experimental...

Intravenous administration of small amounts (0,1 mg/kg of body weight) of succinyl-choline in dogs results in the increase of blood pressure through nicotine-like effects. The increase of succinyl-choline doses induces at first a lowering of the blood pressure through a muscarine-like effect, then its increase. Atropinization, as well as prealable vagotomy, prevents the lowering of the blood pressure but increases it through a nicotine-like effect. Neomistigmine increases both the nicotinic and the cholinergic (muscarinic) effects of succinyl-choline. The use of alpha-sympatico-mimetic drugs, followed by administration of succinyl-choline, generates hypertension and conjugation of alpha-sympatico-mimetic drugs with lepto-currarine induces hypotension, even when para-sympatic lysis has been performed in advance. Inhibition of the beta-sympatic components, followed by inhibition of the alpha-sympatic ones, prevents the development of the succinyl-cholinic hypotension. These facts indicate that the action of succinyl-choline on the blood pressure depends, to a considerable extent, on the condition of the central nervous system.