Retention deficits induced by acute p-chloroamphetamine following fear conditioning in the rat.
Rats were given four inescapable shocks (1.0 mA) when confined to the right-hand corner of a modified shuttlebox. p-Chloroamphetamine (PCA) injected just before the retention test 24 h later completely blocked the immobile posture that was observed after saline injections. This retention deficit was shown to be selectively associated with 5-hydroxytryptamine (5-HT) release, since the administration of the 5-HT uptake inhibitors zimelidine and citalopram 60 min prior to PCA antagonized this effect. The 5-HT specificity of the deficit was further established by the findings that 5-HT-depleted rats (PCA, 2 x 10 mg/kg, and fenfluramine, 2 x 25 mg/kg), but not NA-depleted rats (DSP4, 1 x 50 mg/kg), or rats treated with zimelidine (2 x 20 mg/kg) 60 min before PCA (2 x 10 mg/kg), showed an almost complete blockade of the retention failure. The data presented may provide a useful experimental model for investigating the efficacy of functional 5-HT activity in the treatment of phobic anxiety.
D000662:Amphetamines / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D001596:Benzylamines / Q000494:pharmacology; D003213:Conditioning, Psychological / Q000187:drug effects*; D005239:Fear / Q000502:physiology*; D010134:Fenclonine / Q000494:pharmacology; D005277:Fenfluramine / Q000494:pharmacology; D008297:Male; D008568:Memory / Q000187:drug effects*; D011903:Raphe Nuclei / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D012153:Retention, Psychology / Q000187:drug effects*; D012701:Serotonin / Q000378:metabolism; D015031:Zimeldine / Q000494:pharmacology; D010133:p-Chloroamphetamine / Q000494:pharmacology*
D000662:Amphetamines; D001596:Benzylamines; D005277:Fenfluramine; D012701:Serotonin; D015031:Zimeldine; D010133:p-Chloroamphetamine; C012102:DSP 4; D010134:Fenclonine