Irritative Deposits from Stainless Steel Electrodes in the Preoptic Rat Brain Causing Release of Pituitary Gonadotropin.

Summary When ovulation was induced by means of stainless steel electrodes in the preoptic area, delivering pulses of varied characteristics, a prominent zone of mild inflammation appeared at the end of the electrode track. When ovulation failed, the zone was characteristically small or absent. Electrolysis with direct current, 10 μA or more for 20 sec or longer, proved uniformly effective in causing ovulation. Substitution of platinum electrodes for stainless steel usually gave negative results. Microinjection of FeCl3 solution into the preoptic tissue induced ovulation, while injection of similar amounts of acidified NaCl did not. Finally, electrolysis stimulated ovulation when electrodes of reagent grade iron wire were used, but not when similar electrodes of platinum were employed. It is concluded that iron and perhaps other metals electrolytically deposited from electrodes of stainless steel (or nichrome) produce irritative foci whose stimulative action on certain neurons continues long after the flow of electric current has ceased.