Role of voltage-gated cation channels and axon reflexes in the release of sensory neuropeptides by capsaicin from isolated rat trachea.
In order to reveal the role of axon reflexes and sensory receptors in sensory neuropeptide release in response to capsaicin, liberation of substance P, calcitonin gene-related peptide and somatostatin from isolated rat tracheae was investigated in the presence of voltage-sensitive Na(+) and Ca(2+) channel blocking agents. Neuropeptide release induced by capsaicin (10 nM) remained unchanged in the presence of 25 mM lidocaine, 1 microM tetrodotoxin or the N-type Ca(2+) channel inhibitor, omega-conotoxin GVIA (100-300 nM). Peptide release by 100 pulses of 2 Hz field stimulation was prevented by lidocaine or tetrodotoxin. Omega-agatoxin TK (250 nM) significantly inhibited and Cd(2+) (200 microM) prevented capsaicin-induced neuropeptide release. These results suggest that chemical stimulation-induced neuropeptide release does not involve activation of fast Na(+) channels or N- and P-type voltage-dependent Ca(2+) channels, but contribution of Q-type Ca(2+) channels is possible. Sensory neuropeptides are released by capsaicin from sensory receptors without axon reflexes.
Németh
József
J
Neuropharmacology Research Group of the Hungarian Academy of Sciences, Pécs, Hungary.
Helyes
Zsuzsanna
Z
Oroszi
Gábor
G
Jakab
Balázs
B
Pintér
Erika
E
Szilvássy
Zoltán
Z
Szolcsányi
János
J
D060848:Agatoxins; D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D001369:Axons / Q000187:drug effects* / Q000502:physiology; D002104:Cadmium / Q000494:pharmacology; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects* / Q000502:physiology; D002211:Capsaicin / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D005260:Female; D066298:In Vitro Techniques; D008012:Lidocaine / Q000494:pharmacology; D008297:Male; D009479:Neuropeptides / Q000378:metabolism*; D051381:Rats; D012018:Reflex / Q000187:drug effects; D015222:Sodium Channels / Q000187:drug effects* / Q000502:physiology; D013004:Somatostatin / Q000378:metabolism; D013111:Spider Venoms / Q000494:pharmacology; D013373:Substance P / Q000378:metabolism; D013779:Tetrodotoxin / Q000494:pharmacology; D014132:Trachea / Q000187:drug effects* / Q000294:innervation / Q000502:physiology; D020866:omega-Conotoxin GVIA / Q000494:pharmacology
D060848:Agatoxins; D000779:Anesthetics, Local; D002121:Calcium Channel Blockers; D015220:Calcium Channels; D009479:Neuropeptides; D015222:Sodium Channels; D013111:Spider Venoms; C083855:omega-agatoxin-Aa4b; D002104:Cadmium; D013373:Substance P; D013779:Tetrodotoxin; D013004:Somatostatin; D020866:omega-Conotoxin GVIA; D008012:Lidocaine; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin