THE EFFECTS OF HYDERGINE ON THE MAO ACTIVITY OF THE AGED AND ADULT-RAT BRAIN

Despite the fact that hydergine has been used in the treatment of deme ntia for many years, its mechanism of action is still not clear. Curre nt studies imply that the major effect of hydergine may be the modulat ion of synaptic neurotransmission rather than solely increasing blood flow as was once thought. A prominent feature that accompanies aging i s an increase in monoamine oxidase (MAO) levels which results in decre ased availability of catecholamines in the synaptic cleft. The aim of this study was to determine the effects of hydergine on the MAO activi ty in different brain regions (cortex, olfactory bulb, hypothalamus, h ippocampus, striatum, cerebellum) of old (30 months) and adult (12 mon ths) male Sprague-Dawley rats. In cortex and olfactory bulb MAO levels were higher in the aged group. In hippocampus and hypothalamus hyderg ine treatment caused significant decreases in MAO levels. An interacti on between age and hydergine treatment was observed in the hypothalamu s, hippocampus and cerebellum. The hydergine effect was more pronounce d in the aged group in the hypothalamus and cerebellum, and more prono unced in the adult in the hippocampus. Our findings imply that increas ed brain MAO activity in aging can be modified by hydergine treatment in some brain regions.