Changes in [125I]hCGRP binding in rat spinal cord in an experimental model of acute, peripheral inflammation.
[125I]Human calcitonin gene-related peptide ([125I]hCGRP) binding in the dorsal horn of the spinal cord exhibited differential changes among laminae over time in response to unilateral adjuvant-induced inflammation. In laminae I/II, 4 days after induction of inflammation, the binding decreased 36% on the side of the spinal cord ipsilateral to the inflammation, while there was no change on the contralateral side. The decrease ipsilateral to inflammation was due primarily to a decrease in the Bmax of the high affinity binding site for CGRP. In lamina V, the binding increased 18% on both sides of the spinal cord at the same time point. In lamina X, the binding increased 16% on both sides of the spinal cord at 2 days after induction of inflammation and remained increased at 8 days. The increases in [125]hCGRP binding in laminae V and X were primarily due to a decrease in the Kd of the low affinity binding site for CGRP. the accompanying hyperalgesia was first measured at 2 days after induction of inflammation and persisted at 8 days. Because the changes in [125I]hCGRP binding did not parallel the hyperalgesia accompanying the unilateral adjuvant-induced inflammation, we believe that CGRP receptors are not directly involved with the hyperalgesia but may be involved with other plastic changes observed in the spinal cord during unilateral adjuvant-induced inflammation.
Galeazza
M T
MT
University of Minnesota, Department of Cell Biology and Neuroanatomy, School of Medicine, Minneapolis 55455.
Stucky
C L
CL
Seybold
V S
VS
D000208:Acute Disease; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism*; D004195:Disease Models, Animal; D006801:Humans; D006930:Hyperalgesia / Q000150:complications / Q000378:metabolism; D007249:Inflammation / Q000139:chemically induced / Q000150:complications / Q000378:metabolism; D007457:Iodine Radioisotopes; D008297:Male; D009412:Nerve Fibers / Q000378:metabolism; D009475:Neurons, Afferent / Q000378:metabolism; D010523:Peripheral Nervous System Diseases / Q000139:chemically induced / Q000150:complications / Q000378:metabolism*; D011869:Radioligand Assay; D051381:Rats; D017207:Rats, Sprague-Dawley; D018003:Receptors, Calcitonin; D011956:Receptors, Cell Surface / Q000378:metabolism; D013116:Spinal Cord / Q000378:metabolism*
D007457:Iodine Radioisotopes; D018003:Receptors, Calcitonin; D011956:Receptors, Cell Surface; D015740:Calcitonin Gene-Related Peptide