AIM: To observe the spontaneous unit discharge of the amygdoid nucleus without or with noxious stimulation in heroin-dependent rats. METHODS: The experiment was carried out at the Staff Room of Physiology, Guiyang Medical College from December 2004 to February 2005. Forty-five healthy SD rats were randomized into heroin-dependence group (n=25) and control group (n=20). Heroin was injected subcutaneously in the dependent rats twice a day continuously for 9 days according to the principle of daily increasing ...