Effects of chlordiazepoxide, nicotine and d-amphetamine in the rat potentiated startle model of anxiety.
The effects of acute administration of chlordiazepoxide (2.5 and 5.0mg/kg, i.p.), nicotine (0.05, 0.1 and 0.4mg/kg, s.c.) and d- amphetamine (0.5 and 1.0mg/kg, i.p.) on rat potentiated startle were investigated. Chlordiazepoxide, 2.5 and 5.0mg/kg, attenuated potentiation of startle, indicating an anxiolytic profile, although the effect of the higher dose was less marked and was accompanied by a reduction in overall startle response, probably reflecting drug-induced sedation. Nicotine at doses of 0.05 and 0.4mg/kg had no significant effects in this test. However, 0.1mg/kg nicotine eliminated potentiation of startle (in two separate experiments), an action comparable to that of 2.5mg/kg chlordiazepoxide. d-Amphetamine at doses of 0.5 and 1.0mg/kg did not significantly influence potentiation of startle. The results suggest that nicotine has an anxiolytic profile in the potentiated startle paradigm which is not due to its psychostimulant properties.
Department of Psychology, Birkbeck College, University of London, Malet Street, London WC1E 7HX, UK.
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