BEHAVIORAL AND CARDIAC RESPONSES TO MILD STRESS IN YOUNG AND AGED RATS - EFFECTS OF AMPHETAMINE AND VASOPRESSIN

PHYSIOLOGY & BEHAVIOR

卷:51

Article

关键词: AGING;    IMMOBILITY BEHAVIOR;    AUTONOMIC RESPONSES;    BRADYCARDIA;    STRESS;    AMPHETAMINE;    VASOPRESSIN;   

DOI  :  10.1016/0031-9384(92)90133-M

来源: Elsevier

【 摘 要 】

Young (3-month-old) male Wistar rats showed a relative decrease in heart rate to a sudden silence superimposed on low intensity background noise. This bradycardia was accompanied by immobility behavior. In 26-month-old rats the magnitude of the heart rate response was reduced while immobility behavior remained in the same order of magnitude as in young controls. In the aged rats a shift in autonomic regulation of heart rate in the direction of increased sympathetic influence was indicated by the results obtained by blocking the autonomic input with atropine methyl-nitrate (0.5 mg/kg) or atenolol (1 mg/kg) given subcutaneously (SC) 30 min prior to testing. Pretest (30 min) administration of amphetamine (0.5 mg/kg SC) reinstated the bradycardiac response in aged rats to a level seen in young ones. Arginine-vasopressin (AVP, 10-mu-g/kg SC), administered 60 min before the experiment, markedly facilitated the cardiac response in young animals but failed to restore cardiac responses in aged ones. The immobility behavior in the peptide-treated aged rats was also absent. The present findings suggest that a diminished central aminergic drive in aged rats is causing a reduction of the parasympathetic cardiac response to stress of sudden silence. The results also indicate an age-related vasopressinergic modulation of behavioral and cardiac responses to mild stress.

【 授权许可】

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