Effects of chronic administration of haloperidol, methamphetamine or cocaine on "wet-dog shakes" elicited by stimulation of the rat hippocampus.

We investigated the effect of chronic administration of haloperidol, methamphetamine or cocaine on wet-dog shakes (WDS), as induced by hippocampal stimulation. Although haloperidol, in a dose of 0.5 mg/kg, led to a marked reduction in the number of WDS, a reversion to the control level occurred after administration of haloperidol for 2 weeks. A single administration of methamphetamine and cocaine had no effect on the WDS. The total number of WDS did not change when methamphetamine was administered for 2 weeks and the hippocampus was stimulated 30 min after the last administration. However, the number of WDS after the repeated administration of cocaine was significantly decreased. We tentatively conclude that the hippocampal stimulation-induced WDS may be closely related with dopaminergic functions.