Simultaneous release of substance P- and calcitonin gene-related peptide (CGRP)-like immunoreactivity from isolated muscle of the guinea pig urinary bladder.
Capsaicin (10 microM) induced a tetrodotoxin (TTX)-resistant release of substance P (SP)- and calcitonin gene-related peptide (CGRP)-like immunoreactivity (LI) from muscle strips of the guinea pig isolated urinary bladder. A second application of capsaicin had no effect, indicating a specific effect on sensory nerves (desensitization). In functional experiments, capsaicin produced a phasic contraction of isolated bladder strips. This response was TTX-resistant, exhibited desensitization and was specifically antagonized by [D-Pro4, D-Trp7.9, Phe11] SP(4-11) a SP antagonist which also reduced, at a similar extent, the contraction induced by exogenous SP. These findings provide direct neurochemical and functional evidence for a transmitter role for a SP-like peptide(s) from peripheral sensory terminals in the guinea pig urinary bladder.
Maggi
C A
CA
Pharmacology Department, A. Menarini Pharmaceuticals, Florence, Italy.
Santicioli
P
P
Geppetti
P
P
Patacchini
R
R
Frilli
S
S
Astolfi
M
M
Fusco
B
B
Meli
A
A
D000818:Animals; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009132:Muscles / Q000294:innervation* / Q000502:physiology; D009475:Neurons, Afferent / Q000187:drug effects / Q000378:metabolism*; D009479:Neuropeptides / Q000378:metabolism*; D011863:Radioimmunoassay; D013373:Substance P / Q000378:metabolism*; D013552:Swine; D013779:Tetrodotoxin / Q000494:pharmacology; D001743:Urinary Bladder / Q000187:drug effects / Q000294:innervation* / Q000502:physiology
D009479:Neuropeptides; D013373:Substance P; D013779:Tetrodotoxin; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin