AbstractThe influence of 49 compounds, among them 12 analgesics, on “wet dog” shaking (WDS) induced by thyroliberin (TRH) in rats has been investigated. WDS was dose dependently reduced by all of the analgesics and by 20 of the other drugs. The following compounds were the most active (ED50 values in parentheses): clonidine (5.4 μg/kg), fentanyl (9.6 μg/kg), oxotremorine (21 μg/kg), apomorphine (0.25 mg/kg), amphetamine (0.30 mg/kg), tetrabenazine (0.38 mg/kg), morphine (0.78 mg/kg), chlorpromazine (1.0 mg/kg), and ergotamine (1.2 mg/kg). Both agonists and antagonists of noradrenergic, dopaminergic, serotonergic, and GABA‐ergic functions were inhibitors of WDS, and antinociceptive activity was shared by most of the effective drugs.Thus, WDS or head‐shaking induced by TRH must be considered to be an expression of headache rather than such other causes as heat gain mechanisms or tremor induction. Prevention of TRH‐induced WDS may be used as a test of analge