Exposure to calcium-free medium protects sensory fibers by capsaicin desensitization.
Capsaicin (1 microM) produces a tetrodotoxin-resistant contraction of the rat isolated urinary bladder ascribable to neuropeptide release from sensory nerves. A second application of capsaicin (1-10 microM) up to 5 h from the first one was ineffective, indicating complete desensitization. However, if the first exposure to capsaicin was made after a prolonged incubation in a Ca-free medium containing EDTA (0.1 mM), a second application of capsaicin (1 microM) was still able to induce a contraction, thus indicating protection from desensitization.
Santicioli
P
P
Pharmacology Department, Research Laboratories, A. Menarini Pharmaceuticals, Florence, Italy.
Patacchini
R
R
Maggi
C A
CA
Meli
A
A
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002211:Capsaicin / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009475:Neurons, Afferent / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D001743:Urinary Bladder / Q000187:drug effects / Q000294:innervation* / Q000502:physiology
D002211:Capsaicin; D002118:Calcium