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Differences in dopamine responsiveness to drugs of abuse in the nucleus accumbens shell and core of Lewis and Fischer 344 rats
Author(s) -
Cadoni Cristina,
Chiara Gaetano Di
Publication year - 2007
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2007.04795.x
Subject(s) - nucleus accumbens , microdialysis , amphetamine , dopamine , morphine , chemistry , pharmacology , endocrinology , medicine
The use of inbred rat strains provides a tool to investigate the role of genetic factors in drug abuse. Two such strains are Lewis and Fischer 344 rats. Although several biochemical and hormonal differences have been observed between Lewis and Fischer 344 strains, a systematic comparison of the effect of different drugs of abuse on dopamine (DA) transmission in the shell and core of the nucleus accumbens of these strains is lacking. We therefore investigated, by means of dual probe microdialysis, the effect of different doses of morphine (1.0, 2.5, and 5.0 mg/kg), amphetamine (0.25, 0.5, and 1.0 mg/kg) and cocaine (5, 10, and 20 mg/kg) on DA transmission in the shell and in the core of nucleus accumbens. Behavior was monitored during microdialysis. In general, Lewis rats showed greater DA responsiveness in the NAc core compared to F344 rats except after 2.5 mg/kg of morphine and 20 mg/kg of cocaine. In the NAc shell, different effects were obtained depending on drug and dose: after 1.0 mg/kg of morphine no strain differences were observed, at 2.5 and 5.0 mg/kg Lewis rats showed greater increase in DA in the NAc shell. Following amphetamine and cocaine challenge, Lewis rats showed greater DA increase in the shell after 0.25 mg/kg of amphetamine and 20 mg/kg of cocaine. Behavioral activation was greater in Lewis rats in response to the lowest dose of morphine (1.0 mg/kg), to the highest dose of amphetamine (1.0 mg/kg) and to all doses of cocaine. These differences might be the basis for the different behavioral responses of these strains to drugs of abuse.