Age-related alterations in noradrenergic neurotransmission in Sprague-Dawley and Fischer 344 rat strains

This study compares the electrophysiological effects of locally applied norepinephrine and phencyclidine between 3 month old, 18.20 month old, and 24–26 month old Sprague-Dawley and Fischer 344 rats. Micro-pressure injection through multi-bareled micropipettes was used to apply drugs and record depressant effects on the discharge rate of single cerebellar Purkinje neurons. Neurons from the 3 month old animals were significantly more sensitive to locally applied norepinephrine and phencyclidine than cerebellar Purkinje cells recorded from the older age groups. These results were observed in both rat strains tested. The results suggest that decreased post-synaptic sensitivity to norepinephrine is a concomitant of aging in these animals.