Biological Sciences

Moore, Jack, Autoradiographic localization of carbachol-induced second messenger response in the rat spinal cord following inflammation. Doctor of Philosophy (Biology), May 2002, 59 pp., 15 illustrations, references, 116 titles. This study examined central mechanisms of persistent pain using an autoradiographic technique to localize phosphoinositide hydrolysis (PI) in the rat spinal cord dorsal horn. The lateral half of laminae I-II showed the highest levels of baseline PI turnover and carbachol-stimulated PI turnover in normal animals as well as after inflammation. Inflammation resulted in increased baseline PI turnover in this region of the ipsilateral (76%) and contralateral (65%) dorsal horns. Carbachol increased PI turnover in this region in normal rats (55%) and following inflammation (ipsilateral: 46%, contralateral: 45%). The absolute magnitudes of these increases were 1.85, 2.71, and 2.51 nCi/mg, respectively. The results of this study demonstrate the involvement of PI turnover in neural mechanisms of persistent pain, and provide evidence for the involvement of cholinergic systems in this process. Because spinal cholinergic systems have been reported to b