Presence of mRNA for the vanilloid receptor in frog skeletal muscle

• Published in: The FASEB journal 2010-04, Vol.24 (S1), p.lb664-lb664
• Main Authors: Socorro Ortiz‐Mesina, Monica, Huerta, Miguel, Castro, Elena, Montoya‐Perez, Rocío, Saavedra‐Molina, Alfredo, Sánchez‐Pastor, Enrique, Urzúa, Zorayda, Trujillo, Xóchitl
• Format: Article
• Language: English
• ISSN: 0892-6638; 1530-6860
• DOI: 10.1096/fasebj.24.1_supplement.lb664

We explored the presence of the vanilloid receptor (TRPV1) in the frog skeletal muscle by identifying the mARN for TRPV1 by RT‐PCR using as positive control the rat muscle and exploring the action of capsaicin on caffeine evoked contractures. Tension recording experiments were carried out on bundles from the slow cruralis and the fast bundles from the extensor digitorum longus muscle. Tension evoked by caffeine (6 mM) in the absence or presence of capsaicin and capsazepine was compared. In the slow muscle fibers, capsaicin (5 and 10 μM) diminished the maximum tension until 91.24 ± 2.53, and 85.15 ± 1.2 % respecting to control. This effect was blocked after application of capsazepine (10 μM). In the fast muscle fibers, capsaicin (1 and 10 μM) diminished the maximum tension until 79.4 ± 1.84 and 71.37 ± 3.4 %, regarding to control. However, this effect was partially reverted in the presence of capsazepine (1 μM). mRNA for TRPV1 was detected in the frog slow cruralis muscle, but not for the fast EDL muscle. Capsaicin modulates tension in the slow skeletal muscle fibers possibly via TRPV1 receptor. Also, results in the fast skeletal muscle fibers suggest an independent effect of capsaicin on TRPV1 and possibly directly on some step of the E‐C coupling. Financed by CONACyT‐Mexico grant 83113 to MH. MOM, RMP, ZU received CONACyT fellowship.