EFFECT OF AGING ON PSYCHOLOGICAL STRESS-INDUCED INCREASES IN NORADRENALINE RELEASE IN THE RAT ANTERIOR HYPOTHALAMUS - AN IN-VIVO MICRODIALYSIS STUDY

Basal and psychological stress-induced noradrenaline (NA) release were studied by intracerebral microdialysis in the hypothalamus of rats ag ed 9 weeks or 12 months. Basal NA output was not significantly differe nt between young (9-week-old; 2.11 +/- 0.22 pg/20 min) and aged (12-mo nth-old; 2.29 +/- 0.34 pg/20 min) rats. Psychological stress for 20 mi n significantly increased NA release in both groups (186% and 142% of baseline at 9 weeks old and 12 months old, respectively); however, the increase in aged rats was significantly lower than that in young rats (P < 0.01). This finding suggests that the noradrenergic neuronal res ponse to psychological stress is attenuated in aged rats. (C) 1997 Els evier Science B.V.