Ultrasonic vocalizations.

Effects of LPS (100 μg/kg) and zinc (ZnSO4; 2 mg/kg) on the 22-kHz ultrasonic vocalizations in adult male rats after a restraint stress challenge. SAL+SAL, saline injection followed by another saline injection 1 h later; LPS+SAL, LPS injection followed by a saline injection 1 h later; LPS+Zn, LPS injection followed by a zinc injection 1 h later; SAL+Zn, saline injection followed by a zinc injection 1 h later (n = 10 per group). The data are expressed as the mean ± SEM. (DOCX)