On the mechanism of mergocryptine-induced suppression of dopamine turnover in the rat striatum.
The effect of mergocryptine, a new ergot alkaloid, on the cerebral dopaminergic systems was examined using Wistar rats. The administration of mergocryptine (1 and 10 mg/kg i.p.) induced a significant suppression of striatal dopamine (DA) turnover. In vitro addition of mergocryptine (0.01-100 microM) induced a dose-dependent suppression of the release of [3H]DA from striatal slices. Mergocryptine inhibited [3H]apomorphine binding to a striatal synaptosomal fraction, and its IC50 value was found to be 0.23 microM. Pretreatment with apomorphine (100 micrograms/kg s.c.) showed an additive effect on the mergocryptine (10 mg/kg)-induced suppression of DA turnover. These results suggest that mergocryptine may induce the suppression of striatal DA turnover by reducing DA release via the stimulation of presynaptic dopaminergic autoreceptors.
Hashimoto
T
T
Department of Pharmacology, Kyoto Prefectural University of Medicine, Japan.
Katsura
M
M
Kuriyama
K
K
D000818:Animals; D001058:Apomorphine / Q000378:metabolism*; D001552:Benzazepines / Q000378:metabolism; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism*; D004873:Ergolines / Q000494:pharmacology*; D006207:Half-Life; D008297:Male; D011813:Quinuclidinyl Benzilate / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects* / Q000378:metabolism; D013134:Spiperone / Q000378:metabolism
D001552:Benzazepines; D004873:Ergolines; D011954:Receptors, Dopamine; D013134:Spiperone; D011813:Quinuclidinyl Benzilate; C067380:mergocriptine; D001058:Apomorphine; D004298:Dopamine