Changes in substance P and calcitonin gene-related peptide binding in the dorsal horn of rat spinal cord following pronase-induced deafferentation

Abstract

Quantitative receptor autoradiography was used to evaluate potential alterations in substance P (SP) and calcitonin generelated peptide (CGRP) binding in the L4 spinal segment of rats following unilateral poisoning of the sciatic nerve with pronase. Ten days after pronase-induced deafferentation there was a significant increase in SP and CGRP binding in the superficial (I-II) and deeper (II-IV) laminae of the dorsal horn ipsilaterally. Densitometric measurements revealed a 50% return towards normal values for SP binding by 90 days postpronase injection in all laminae examined, while the density of CGRP binding showed a partial return towards normal values for laminae III-IV only. These differential responses may be indicative of the mechanisms underlying pronase-induced peripheral neuropathy.

• Substance P, Cgrp, Receptor Binding, Dorsal Horn, Neuropathic Pain, Plasticity