Effect of the serotonin agonist 8-OH-DPAT on the sensorimotor system of the rat

8-Hydroxy-2-(di-n-propylamino)-tetralin hydrobromide (8-OH-DPAT, 2 mg/kg) i s used to induce perseverative behavior in rats in a T-maze as a model for obsessive-compulsive disorder (OCD). Using the open-field test, radiant hea t test, and the test with von Frey filaments, we examined whether alteratio ns in sensorimotor functioning could contribute to the perseverative tenden cies in this model by measuring differences in left versus right hind paw r eactions after 8-OH-DPAT administration (2 mg/kg, sc). Also, the effect of repeated 8-OH-DPAT administration on sensorimotor functioning was tested ev ery third day. 8-OH-DPAT administration induced a significantly decreased s ensorimotor performance in the open-field test, an increased threshold for noxious thermal stimulation (increased withdrawal latency, WL, and decrease d elevation time, ET) in the radiant heat test, and a decreased nociceptive threshold for mechanical stimulation in the test with von Frey filaments. All changes in sensorimotor functioning were similar for left and right hin d paws suggesting that, these changes as measured with the tests in the pre sent study, are not likely to contribute to the perseverative behavior of r ats in a T-maze. Further, repeated administration of 8-OH-DPAT had no effec t in the radiant heat test and the test with the Frey filaments, but produc ed a tolerance effect in the open-field test. (C) 2001 Elsevier Science Inc . All rights reserved.