title: Repeated stress increases locomotor response to amphetamine.
abstract: Adult male rats submitted to mild, 20 min electric foot shock sessions for 10 days displayed an enhanced locomotor response to 0.75 mg/kg (+)amphetamine 24 h after the last shock session, when compared to non-stressed controls. This effect was still present in rats specifically deprived of their forebrain noradrenergic innervation, suggesting the involvement of a dopaminergic mechanism. Cortical and limbic dopamine turnover which increased immediately after acute and repeated foot shocks returned to normal 24 h later, at the time of the pharmacological testing. This fact indicates that a permanent modification of the basal DA activity is not responsible for the above effect of stress. Locomotor hyperactivity produced by 0.6 mg/kg apomorphine was enhanced in experimental animals, while hypoactivity resulting from the injection of 0.05 mg/kg apomorphine was similar in control and shocked rats. This latter result suggests the existence of an increased postsynaptic DA sensitivity as a result of repeated stress.
mesh_terms: D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000661:Amphetamine / Q000494:pharmacology*; D000679:Amygdala / Q000378:metabolism; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D002540:Cerebral Cortex / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D006801:Humans; D006892:Hydroxydopamines / Q000633:toxicity; D008032:Limbic System / Q000378:metabolism; D008297:Male; D008781:Methyltyrosines / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects*; D009638:Norepinephrine / Q000502:physiology; D009714:Nucleus Accumbens / Q000378:metabolism; D016627:Oxidopamine; D051381:Rats; D011919:Rats, Inbred Strains; D013315:Stress, Psychological / Q000378:metabolism / Q000503:physiopathology*; D019805:alpha-Methyltyrosine
chemical_list: D006892:Hydroxydopamines; D008781:Methyltyrosines; D015102:3,4-Dihydroxyphenylacetic Acid; D019805:alpha-Methyltyrosine; D016627:Oxidopamine; D000661:Amphetamine; D001058:Apomorphine; D004298:Dopamine; D009638:Norepinephrine