Liu YP, Tung CS, Lin PJ, Wan FJ. Role of nitric oxide in amphetamine-induced sensitization of schedule-induced polydipsic rats.
Psychopharmacology (Berl) 2011;
218:599-608. [PMID:
21625906 DOI:
10.1007/s00213-011-2354-9]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Accepted: 05/08/2011] [Indexed: 10/18/2022]
Abstract
RATIONALE
Repeated injections of amphetamine (AMPH) can progressively augment behavioral responses, a phenomenon known as behavioral sensitization. AMPH-induced behavioral sensitization can be demonstrated in a rat model of schedule-induced polydipsia (SIP).
OBJECTIVES
The aim of this study was to investigate the effects of a nonspecific nitric oxide (NO) synthase inhibitor, N(G)-nitro arginine methyl ester (L: -NAME), on the AMPH sensitization effects in SIP.
MATERIALS AND METHODS
Rats were trained to establish SIP. The induction of AMPH sensitization in SIP was tested in either the home cage or a test cage. L: -NAME (50 mg/kg, i.p.) was co-administered with AMPH for five consecutive days, and its effect on induction was examined 3 and 14 days after withdrawal. The effect of L: -NAME on expression was examined on the final testing day by co-administration with AMPH in previously sensitized SIP rats.
RESULTS
AMPH-induced behavioral sensitization in SIP rats only occurred when AMPH was injected in the home cage. Pretreatment with L: -NAME successfully blocked the induction of this sensitization following both short and long-term withdrawal. Once sensitization had been established, L: -NAME had no further influence.
CONCLUSIONS
These results suggest that SIP behavior observed after repeated AMPH treatment is mediated by an NO-associated mechanism.
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