ACTIVIN SELECTIVELY ABOLISHES HIPPOCAMPAL LONG-TERM POTENTIATION INDUCED BY WEAK TETANIC STIMULATION IN-VIVO

Although modulation of hippocampal synaptic plasticity by neurotrophin s or growth factors has recently become an extensively investigated su bject, there are no reports arguing for the contribution of the transf orming growth factor (TGF)-beta superfamily. In the present study, we examined the effect of activin, a member of the TGF-beta superfamily, on long-term potentiation (LTP) of the dentate gyrus in anesthetized r ats. Activin significantly impaired the formation of LTP induced by te tanic stimulation (60 Hz for 0.27 sec), but not that by strong tetanic stimulation (60 Hz for 0.5 sec). These results suggest that activin s electively blocks the induction of LTP evoked by threshold tetanic sti mulation.