Etorphine, when applied iontophoretically, could strikingly depress the late burst of evoked discharge in all of the 22 convergent units tested, leaving the initial burst unaffected.

• 对于非会聚性单位羟戊甲吗啡能选择性地抑制长潜伏期诱发放电反应，而对短潜伏期的则无明显影响。