EFFECTS OF NEMATODE INFECTION ON SENSITIVITY TO INTESTINAL DISTENSION- ROLE OF TACHYKININ NK2 RECEPTORS

Distension of the rat intestine causes a depressor response which is p redictive of nociception. This study investigated the effects of previ ous infection with Nippostrongylus (N.) brasiliensis on the sensitivit y to intestinal distension and the role of tachykinin NK2 receptors. T he tachykinin NK2 receptor antagonist, SR48968 piperidino)-2-(3,4-dich lorophenyl)butyl]benzamide) inhibited the nociceptive response (ED50 = 0.7 mg/kg) in control rats. In post-N. brasiliensis-infected rats sen sitivity to intestinal distension was increased which was accompanied by all increase in the apparent potency value of SR48968 (ED50 = 0.1 m g/kg). The hypersensitivity was limited to areas of hypermastocytosis. It is concluded that the post-inflammatory changes that occur in post -infected rats increase visceral sensitivity and the apparent potency of tachykinin NK2 receptor antagonists. (C) 1997 Elsevier Science B.V.