Epinephrine potentiates antipsychotic, but not cataleptogenic effect of haloperidol in rats.
Intramuscular injection of haloperidol or epinephrine in a minimum effective dose produces the maximum antipsychotic effect in rat model of schizophrenia, i.e. completely removes stereotypy, hyperlocomotion, and ataxia induced by MK-801. Haloperidol in the specified dose induces catalepsy, while epinephrine exhibits no cataleptogenic effect. Combined intramuscular injection of haloperidol and epinephrine in the threshold doses, ineffective in monotherapy, causes the maximum antipsychotic effect, but not catalepsy. Preliminary anesthesia of the gastric mucosa with 1% lidocaine and blockade of intramural ganglia in the gastric mucosa with hexamethonium completely abolished the potentiated antipsychotic effects produced by combined treatment with haloperidol and epinephrine. Hence, potentiation of the antipsychotic effect of haloperidol with epinephrine is related to stimulation of afferents in the gastric mucosa.
Gmiro
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Institute of Experimental Medicine, Russian Academy of Medical Sciences, St Petersburg, Russia. g2119@online.ru
Serdyuk
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D000818:Animals; D014150:Antipsychotic Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D002375:Catalepsy / Q000139:chemically induced*; D016291:Dizocilpine Maleate / Q000008:administration & dosage; D004357:Drug Synergism; D004837:Epinephrine / Q000494:pharmacology*; D006220:Haloperidol / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D007273:Injections, Intramuscular; D008297:Male; D051381:Rats
D014150:Antipsychotic Agents; D016291:Dizocilpine Maleate; D006220:Haloperidol; D004837:Epinephrine