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RATIONALE Nicotinic receptors have been implicated in attentional performance. Nicotine can improve attention in animals and humans, but knowledge about relevant receptor subtypes is very limited. OBJECTIVES The aim was to examine the role of alpha7 receptors in attentional performance of mice and in effects of nicotine. MATERIALS AND METHODS Mice with(More)
Rats shifted from 4% to 32% sucrose displayed successive negative contrast by initiating significantly fewer bouts of licking than control rats maintained on 4% sucrose. No significant increase in dopamine (DA) efflux in the nucleus accumbens (NAc) was observed during consumption of 4% sucrose by rats shifted from 32%. In contrast, consumption of 4% sucrose(More)
RATIONALE Animals trained to lick for a sucrose solution of a given incentive value that subsequently encounter an incentive downshift (i.e. 32-4% sucrose) display an exaggerated decrease in the amount consumed, relative to unshifted controls. This change has been classified as a successive negative contrast (SNC) effect. The emotional component to this(More)
Distinct lines of evidence indicate that glutamate plays a primary role in modulating cognitive functions. Notably, competitive glutamate receptor antagonists acting at ionotropic N-methyl-d-aspartate (NMDA) or metabotropic glutamate 5 (mGlu5) receptors impair cognitive performance. Conversely, nicotine and other psychostimulants stimulate glutamatergic(More)
In spite of the addictive properties of cannabinoids, under certain circumstances, they can evoke strong anxiogenic and aversive responses in humans and in animal tests of anxiety. Effects of different doses of CP 55,940 (10, 20, and 40 microg/kg) were tested in the low-light, familiar (LF) apparatus test condition of the social interaction test. The(More)
The effects of mild food deprivation (7 days of food restricted to once daily feeding to maintain body weights at 85% of free-feeding weights) were examined in adult male and female and adolescent female rats tested in the elevated plus maze and social interaction tests of anxiety. In adult male rats, food deprivation appeared to have an anxiolytic effect(More)
Pharmacological manipulations that alter dopamine (DA) at DA receptor subtypes produce reductions in feeding behaviour. What remains uncertain is the exact way in which these reductions in feeding are achieved as a consequence of differing drug actions at separate receptor subtypes. In this study our aim was to compare the anorectic effects of the(More)
Nicotine has bimodal effects on anxiety, with low doses having an anxiolytic effect and high doses having an anxiogenic effect. The dorsal hippocampus is one of the brain areas that mediate the anxiogenic effect of nicotine through enhanced 5-HT release, but the nAChR subtype(s) that mediate these effects are not known. Intrahippocampal administration of a(More)
Alpha7 nicotinic acetylcholine receptors (alpha7 nAChRs) and 5-hydroxytryptamine 1A (5-HT1A) receptors have been implicated in the anxiogenic effects of centrally administered nicotine, but the receptors that mediate the anxiogenic effects of systemic nicotine are not known. This study explored whether competitive nAChR antagonists(More)
Conditioning to the anxiogenic effects of nicotine has previously been demonstrated in the social interaction test and there was no generalization of conditioning between the social interaction and elevated plus-maze tests. Because the two tests generate distinct states of anxiety, the conditioning could have occurred to the cues associated with the test(More)