Thiorphan increases capsaicin-evoked release of substance P from slices of dorsal spinal cord of guinea pig.
Capsaicin-evoked release of substance P-like immunoreactivity (SP-LI) from dorsal horn slices of guinea pig spinal cord was unaffected by incubation with the converting enzyme inhibitor captopril (10 microM). However, incubation with the endopeptidase 24.11 inhibitor, thiorphan (10 microM), induced a 2.44-fold increase of capsaicin-evoked SP-LI release, leaving the capsaicin-evoked release of calcitonin gene-related peptide (CGRP)-LI unchanged. Endopeptidase-24.11 activity was higher in homogenates of the dorsal than ventral spinal cord. Endopeptidase-24.11 might be involved in the inactivation of SP released from central endings of primary sensory neurons.
Geppetti
P
P
Institute of Internal Medicine and Clinical Pharmacology, University of Florence, Italy.
Santicioli
P
P
Rubini
I
I
Spillantini
M G
MG
Maggi
C A
CA
Sicuteri
F
F
D000818:Animals; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin / Q000494:pharmacology*; D002216:Captopril / Q000494:pharmacology; D005260:Female; D006168:Guinea Pigs; D007700:Kinetics; D008297:Male; D015260:Neprilysin / Q000037:antagonists & inhibitors / Q000378:metabolism; D009479:Neuropeptides / Q000378:metabolism; D013116:Spinal Cord / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D013373:Substance P / Q000378:metabolism*; D015244:Thiorphan / Q000494:pharmacology*
D009479:Neuropeptides; D013373:Substance P; D002216:Captopril; D015244:Thiorphan; D015260:Neprilysin; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin