Chronic treatment with atypical neuroleptics sulpiride and metoclopramide increases striatal enkephalins in rat brain.
The aim of this paper was to study the effect of a single dose of 14, 30 or 90 days' administration of sulpiride (SUL) (50 or 100 mg/kg), metoclopramide (MET) (20 or 40 mg/kg) or haloperidol (HAL) (2 mg/kg) on the level of leu- and met-enkephalin (ENK) in the striatum. A dose and time dependent increase of the striatal ENK level was observed after chronic administration of atypical neuroleptics SUL or MET as well as after chronic treatment with a classical cataleptogenic neuroleptic HAL. The effect of chronic administration of HAL on the striatal level of leu-enkephalin was stronger than after SUL but lower than after MET treatment. It is concluded that: 1) Chronic administration of atypical neuroleptics results in the increased level of striatal ENK similar to that after chronic treatment with classical cataleptogenic neuroleptics; 2) Apparently both more or less selective antagonists of dopaminergic D2 receptors activate the enkephalinergic system in the striatum.
Department of Clinical Pharmacology, Silesian Medical Academy, Katowice, Poland.
Z S
ZS
Herman
M
M
Huzarska
D000818:Animals; D004305:Dose-Response Relationship, Drug; D004745:Enkephalins / Q000378:metabolism*; D006220:Haloperidol / Q000494:pharmacology; D008297:Male; D008787:Metoclopramide / Q000494:pharmacology*; D017072:Neostriatum / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013469:Sulpiride / Q000494:pharmacology*; D013997:Time Factors
D004745:Enkephalins; D013469:Sulpiride; D006220:Haloperidol; D008787:Metoclopramide