Capsaicin-evoked neuropeptide release is not dependent on membrane potential changes.
In high K(+)-depolarized spinal cord slices, capsaicin evoked the in vitro release of substance P and calcitonin gene-related peptide (CGRP) from central terminals of C-fibre afferents. This shows that capsaicin-induced release of neuropeptides from sensory afferents is not dependent on membrane potential changes, and that capsaicin-induced Ca2(+)-influx into nerve terminals does not require activation of voltage-sensitive calcium channels (VSCC). On the other hand, in the continuous presence of capsaicin, high K+ did not evoke release of CGRP, but only released substance P, which most likely originated from intrinsic substance P- containing neurones in the spinal cord.
Donnerer
J
J
Department of Experimental and Clinical Pharmacology, University of Graz, Austria.
Amann
R
R
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D002211:Capsaicin / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009475:Neurons, Afferent / Q000187:drug effects / Q000378:metabolism; D009479:Neuropeptides / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D013373:Substance P / Q000378:metabolism
D009479:Neuropeptides; D013373:Substance P; D015740:Calcitonin Gene-Related Peptide; D011188:Potassium; D002211:Capsaicin