Fig. 4.
Mean heroin infusions across a range of heroin doses for females (left; n=5) and males (right; n=5) presented as a function of estrus cycle. The data points represent the average number of infusions based on one data point per animal at a given dose and phase of estrous. Results from females indicate a reduction in heroin self-administration during proestrus (P) compared to meta/diestrus (M/D) and estrus (E). Males show reductions in heroin self-administration during the estrus (E) and proestrus (P) phases of their female partners compared to meta/diestrus (M/D). Please note difference in Y-axis between females and males.
