A ROLE OF THE THYMUS AND THYMOSIN-ALPHA-1 IN BRAIN NGF LEVELS AND NGFRECEPTOR EXPRESSION

Using neonatal rats we investigated the role of the thymus and thymosi n-alpha 1 (T-alpha 1) in brain NGF levers. NGF receptor (p75NGFr) expr ession, as well as the activity of choline acetyl-transferase, a choli nergic enzyme regulated by NGF. It is shown that early postnatal thyme ctomy causes a decrease in NGF ill the hippocampus and cortex and p75N GFr distribution in the basal forebrain cholinergic neurons (FBCN). In tracerebral T-alpha 1 injection in thymectomized animals induces a rec overy, albeit not complete, of both NGF and p75NGFr. These findings in dicate that thymectomy affects both the brain NGF producing and respon ding cells and that T-alpha 1 may be one of the thymic hormones involv ed in the regulation of cerebral NGF synthesis. (C) 1998 Elsevier Scie nce B.V.