Abstract
Objectives: Capsaicin, the most pungent constituent of chilli pepper (Capsicum annuum L.), is known to alter the physiological activity of the gut. Capsaicin mediates its action through a transient receptor potential vanilloid type 1 (TRPV1) channel. The action of capsaicin on gut smooth muscle varies from segment to segment in different species. The earlier studies were carried out in adult animals only, and its status in the neonate gut, which is in a development stage, is not known. Objective: Therefore, the present study was done to assess the effect of capsaicin on the large gut of neonates. Materials and Methods: In an organ bath preparation, isometric contractions were recorded from segments of dissected rat colon and rectum. The gut segments were exposed to cumulative concentrations of capsaicin (0.01 nM–3 µM) and a capsaicin-induced contractile response was observed. TRPV1 receptor antagonist capsazepine (1 µM) and a nitric oxide synthase inhibitor, L-NAME (100 µM), were used to assess their blocking effect on capsaicin-induced contractile response. Results: Capsaicin raised contractile tension in the colon and rectum of adult rats but not in neonate rats. In adult rats, capsazepine pre-treatment (1 µM) failed to block the capsaicin-induced response in the colon, but in the lower concentrations, it increased contractile tension in the rectum. Pre-application of L-NAME (100 µM) potentiated capsaicin-induced response in the adult rectum and neonate’s colon but had no effect in the neonate rectum and adult colon. Capsaicin with a low concentration (0.01 nM–0.01 µM) increased contractile frequency in both the colon and rectum of adult rats. However, the effect of capsaicin on frequency was abolished at higher concentrations (0.01 µM–3 µM). A capsaicin-evoked change in contractile frequency in adult rats was blocked by capsazepine and L-NAME. At lower concentrations (0.01 nM–0.01 µM), capsaicin did not show any change in frequency in the neonatal colon, while a decrease in contractile frequency was observed with the higher concentrations (0.1 µM–3 µM) of capsaicin. In neonates, capsazepine pre-treatment produced changes in frequency for both the colon and rectum. However, pre-application of L-NAME decreased frequency in the neonate rectum but not in the colon. Conclusion: Capsaicin-induced changes in contractile activity may or may not involve TRPV1 or the Nitric Oxide (NO) pathway, depending on the part of the large gut and developmental maturity.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.