ABSTRACT
The mechanism of the effect of M-cholinoblockers on the heart rate was analysed. It is suggested on the basis of this analysis that tachycardia induced in reats by muscarinic antagonists was caused by blockade of ther central M1-cholinoceptors which is accompanied with increase in the tone of the sympathetic branch of the autonomic nervous system.
Subject(s)
Muscarinic Antagonists/toxicity , Receptors, Muscarinic/drug effects , Tachycardia/chemically induced , Animals , Arecoline/toxicity , Dichlorvos/poisoning , Heart Rate/drug effects , Poisoning/prevention & control , Rats , Receptor, Muscarinic M1 , Receptor, Muscarinic M2 , Tachycardia/physiopathology , Tremor/chemically induced , Tremor/prevention & controlABSTRACT
The comparative study revealed significant differences in the effects of antimuscarinics on the outcome of intoxication in animals induced by direct and indirect cholinomimetics. The doses of the agents possessing equal choline blocking activity provide different levels of protection at chlorophos-induced intoxication of animals that is not observed at carbacholine-induced intoxication. The differences in the effects of direct and indirect cholinomimetics were used for the elaboration of the methodical approach that made it possible to formulate a hypothesis about the ambivalent character of the action of antimuscarinics. The hypothesis implies that the protective activity of the agents at intoxication by organophosphorus compounds is determined by the ratio of their effects on pre- and postsynaptic cholinoreceptors.
Subject(s)
Antidotes , Parasympatholytics/therapeutic use , Trichlorfon/poisoning , Animals , Carbachol/poisoning , Dose-Response Relationship, Drug , Drug Evaluation, Preclinical , Mice , Receptors, Cholinergic/drug effectsABSTRACT
It was established in experiments on mice that the protective effect of metacine and atropine iodomethylate during chlorophos and acetylcholine intoxication is directly proportional to the peripheral m-cholinolytic activity of the drugs. The protective effect of the doses of metacine and atropine iodomethylate equieffective by the choline-blocking effect was equal during acetylcholine intoxication but differed during chlorophos intoxication. Atropine iodomethylate exhibited a stronger selective peripheral m-cholinolytic action than metacine.
