Chronic treatment with atypical neuroleptics sulpiride and metoclopramide increases striatal enkephalins in rat brain
Herman, Z.S.; Huzarska, M.
Polish Journal of Pharmacology 45(5-6): 493-502
1993
ISSN/ISBN: 1230-6002 PMID: 8012472 Document Number: 418586
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 D-2 receptors activate the enkephalinergic system in the striatum.