Calcitonin gene-related peptide (8-37) does not antagonize calcitonin gene-related peptide in rat spinal cord.
We have examined the effects of intrathecal (i.t.) human calcitonin gene-related peptide (hCGRP) and its C-terminal fragment hCGRP(8-37), a proposed CGRP antagonist, on the flexor reflex in decerebrate, spinalized, unanesthetized rats. I.t. hCGRP at 26 pmol caused a moderate facilitation of the reflex which was not antagonized by hCGRP(8-37) at doses ranging from 26 pmol to 5.2 nmol. Furthermore, hCGRP(8-37) by itself facilitated the reflex, with no signs of inhibition. It is concluded that the spinal CGRP receptor mediating the spinal facilitatory effect of hCGRP is not antagonized by hCGRP(8-37). Thus, it is unlikely that hCGRP(8-37) can be useful as a spinal analgesic.
Xu
X J
XJ
Department of Medical Laboratory Sciences and Technology, Section of Clinical Neurophysiology, Karolinska Institute, Huddinge University Hospital, Sweden.
Wiesenfeld-Hallin
Z
Z
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000037:antagonists & inhibitors / Q000138:chemical synthesis / Q000494:pharmacology*; D004576:Electromyography; D005260:Female; D006801:Humans; D007278:Injections, Spinal; D009119:Muscle Contraction / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000494:pharmacology; D013116:Spinal Cord / Q000737:chemistry* / Q000187:drug effects
D011994:Recombinant Proteins; D015740:Calcitonin Gene-Related Peptide