Fig. 2

Heterogeneous responses of LPGi neurons to naloxone. As shown, naloxone injection in adult morphine-dependent rats causes excitatory (A) and inhibitory (B) responses in rats receiving either saline or morphine during adolescence. Also the intensity of excitatory responses (% of increase) is reduced in rats with history of adolescent morphine exposure. NLX naloxone, Sal saline, Mor morphine. ****P < 0.001, **P < 0.01. Data are expressed as ± standard error of the mean (SEM)