Supersensitivity of cortical neurones of the rat to acetylcholine and L-glutamate following chronic morphine treatment

Abstract
The effect of microelectrophoretically applied L-glutamate and acetylcholine on discharge activity of cortical neurones was studied in naive and in morphine-tolerant/dependent rats. The thresholds for increase in discharge activity elicited by these 2 putative neurotransmitters were 3 times lower in the tolerant/dependent rats than in the naive rats, indicating the development of supersensitivity.