Pronounced hypothermic synergy between systemic baclofen and NOS inhibitor

Baclofen was administered to rats systemically (intraperitoneal, i.p.) by itself or with L-NAME. Baclofen (1-7.5 mg/kg, i.p.) evoked dose-dependent hypothermia. L-NAME (50 mg/kg, i.p.) was ineffective. For combined administration, L-NAME increased the relative potency of baclofen (F=10.77, p<0.05), indicating multiplicative interaction and synergism. The present data reveal a surprising and significant interaction between nitric oxide synthase (NOS) and baclofen-induced hypothermia.