Role of mesencephalic reticular formation in cholinergic-induced catalepsy and anticholinergic reversal of neuroleptic-induced catalepsy.
The present experiments investigate the brain sites involved in the elicitation of catalepsy by cholinergic agonists and neuroleptics. Microinjection of acetylcholine chloride (50 micrograms) in combination with eserine (2.5 micrograms) into the ventral mesencephalic reticular formation (MRF) elicited catalepsy. Microinjection of atropine sulfate (5 micrograms) into the same sites reversed the catalepsy of rats treated with haloperidol (1.5 mg/kg) 2 h earlier, but did not reverse morphine-induced (30 mg/kg, 1 h) catalepsy. Haloperidol (25 micrograms) injected into the nucleus accumbens septi (NAS) resulted in catalepsy as severe as that caused by an identical injection into the caudate nucleus. Catalepsy caused by intraNAS haloperidol occurred with a shorter latency than that resulting from intracaudate haloperidol, and was reversed by systemic scopolamine (0.4 mg/kg). On the basis of these results it is suggested that the ventral MRF is a site for the elicitation of catalepsy by cholinergic agonists and for the reversal of neuroleptic-induced catalepsy by anticholinergics, and that neuroleptic-induced catalepsy involves blockade of dopamine receptors in both the NAS and caudate nucleus.
D000109:Acetylcholine; D000818:Animals; D001285:Atropine; D002375:Catalepsy / Q000139:chemically induced*; D002421:Caudate Nucleus / Q000503:physiopathology; D002799:Cholinergic Fibers / Q000502:physiology; D006220:Haloperidol; D006801:Humans; D008297:Male; D008636:Mesencephalon / Q000503:physiopathology*; D009714:Nucleus Accumbens / Q000503:physiopathology; D010830:Physostigmine; D051381:Rats; D011919:Rats, Inbred Strains; D012154:Reticular Formation / Q000503:physiopathology*; D012601:Scopolamine
D001285:Atropine; D010830:Physostigmine; D012601:Scopolamine; D006220:Haloperidol; D000109:Acetylcholine