EFFECTS OF ACTIVIN-A ON NEURONS ACUTELY ISOLATED FROM THE RAT SUPRAOPTIC NUCLEUS

Nerve fibers containing activin-like immunoreactivity have been shown to be present within the area of the supraoptic nucleus. In this study , whole-cell patch-clamp recordings from supraoptic magnocellular neur osecretory cells were used to characterize the electrophysiological ef fects of this peptide, Nanomolar concentrations of recombinant activin -A caused the appearance of a voltage-independent current reversing ne ar -40 mV. At resting potential, membrane depolarization caused by thi s current was sufficient to accelerate action potential discharge, sug gesting that activin receptors expressed on magnocellular neurosecreto ry cells may play a role in the control of neurohypophysial hormone re lease.