Peripheral inflammation reduces the response of spinal dorsal horn neuronsto an NK3 receptor agonist

The neurokinin receptors NK1 and NK3 are involved in processing nociceptive information in the spinal dorsal horn and in central changes following per sistent peripheral injury. However, little is known about functional change s in these receptor systems, particularly the NK3 receptor. We have perform ed intracellular recordings from spinal dorsal horn neurons in vitro, using spinal cords obtained both from control rats and from those with a periphe ral inflammation induced by carrageenan. Application of the NK1 receptor ag onist, [Sar(9), Met(O-2)(11)]Substance P and the NK3 receptor agonist Senkt ide, produced slow, long lasting depolarizations. The Senktide- but not [Sa r(9), Met(O-2)(11)]Substance P-induced depolarizations were significantly s maller in carrageenan-treated rats. These data indicate an altered role for the NK3 receptor in the spinal dorsal horn following acute peripheral infl ammation. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.