Dziewczapolski G, Menalled LB, Savino MT, Mora M, Stefano FJ, Gershanik O. Mechanism of action of clozapine-induced modification of motor behavior in an animal model of the "super-off" phenomenon.
Mov Disord 1997;
12:159-66. [PMID:
9087973 DOI:
10.1002/mds.870120205]
[Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
We tested the effects of clozapine, and "atypical" neuroleptic with high affinity for the D4 (dopaminergic), and the 5-HT1c and 5-HT2 (serotonergic) receptor subtypes on locomotor activity in an animal model of Parkinson's disease showing a bimodal response curve to increasing doses of a D2 agonist. Sulpiride (D2 antagonist) and ritanserin (5-HT1c and 5-HT2 antagonist) were used for comparison. The D1 agonist SKF 38393 at a dose of 8 mg/kg significantly reversed the akinesia induced by chronic reserpine treatment (1 mg/kg for 5 days) and alpha-methyl-p-tyrosine pretreatment (300 mg/kg). In this model, the addition of a low dose of a D2 agonist, LY 171555 (quinpirole, 1 microgram/kg), inhibited the effects of SKF 38393, whereas the same drug at higher doses (5-50 microgram/kg) restored and potentiated the stimulatory response to D1 stimulation. Clozapine inhibited the inhibitory phase and potentiated the stimulatory phase of the curve. Sulpiride inhibited both phases of the dose-response curve (inhibitory/stimulatory), whereas ritanserin had no effect. We believe these results may reflect a disinhibition phenomenon possible mediated by the blockade by clozapine of a subpopulation of inhibitory, dopamine (DA) receptors belonging to the D2 "family."
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