Figure 4.

Attenuation of acute ethanol withdrawal severity by caudolateral SNr lesions. a, Bilateral SNr-lesioned and sham-lesioned D2 mice were scored for baseline HICs immediately before administration of 4 g/kg ethanol (arrow marks ethanol injection at time 0) and hourly between 2 and 12 h after ethanol administration. Data represent the mean raw scores ±SEM for baseline and postethanol HICs. Alcohol administration initially lowers HIC scores (0–4 h). Later, convulsion scores increase above baseline, indicating a state of withdrawal hyperexcitability, which peaked ∼6 h after ethanol administration. b, Caudolateral SNr lesions significantly reduced ethanol withdrawal scores calculated as AUC (corrected for baseline HIC scores) compared with sham-lesioned groups (p < 0.001). Similarly, animals with lateral SNr lesions (spanning caudal and rostral lateral SNr) showed significantly less severe ethanol withdrawal than sham-lesioned animals (p < 0.005). In contrast, rostrolateral SNr lesions did not alter ethanol withdrawal convulsion severity compared with sham-lesioned control animals (p = 0.8). **p < 0.005.