Chapter 11 Studies of the release of immunoreactive galanin and dynorphin A(1–8) in the spinal cord of the rat

Abstract

Publisher Summary Recent research has identified a number of other compounds that may also function as inhibitory to the transmission of nociceptive information. Dynorphin and galanin are two such compounds although their roles, even in the spinal cord, have been the subject of dissent among investigators. Despite this, galanin and dynorphin may be lead compounds for newer analgesics, and hence, work has been directed at defining the conditions that produce a spinal release of these neuropeptides. This chapter discusses the recent experiments in the laboratory that had examined spinal release of galanin in normal rats and those with peripheral inflammation. From a functional viewpoint dynorphins are enigmatic neuropeptides. At the single cell level, activation of kappa receptors appears to inhibit a voltage sensitive calcium channel, and this may function to reduce transmitter release at nerve endings. The experiments described in the chapter have used microprobes bearing antibodies to porcine dynorphin A (1-8) . The finding of both basal and evoked release of ir-dynorphin A (1-8) in several areas of the spinal cord suggests an involvement of dynorphins in several aspects of spinal cord processing, with release in the superficial horn potentially reflecting a role in antinociception, while that in the deep dorsal hordventral horn may indicate an influence of motor behavior.