The effects of nifedipine and glyceryl trinitrate on anorectal muscle contractions: an “in vitro” study

DOI: 10.4328/JCAM.5893 Received: 30.04.2018 Accepted: 09.06.2018 Published Online: 10.06.2018 Printed: 01.03.2019 J Clin Anal Med 2019;10(2): 207-10 Corresponding Author: Ali Onur Erdem, Department of Pediatric Surgery, Adnan Menderes University, Aydin, Turkey. GSM: +905053882174 E-Mail: aoerdem@adu.edu.tr ORCID ID: 0000-0002-9584-4200 Abstract Aim: Numerous methods have been tried to reduce the anal sphincter spasm occurring in cases with anal fissure. One of these methods is chemical sphincterotomy performed with various drugs. We aimed to show and compare the “in vitro” effects of glyceryl trinitrate and nifedipine, which are among these drugs, in the organ bath, using the rat anal sphincter muscle. Material and Method: We used 18 Wistar-Albino rats in our experimental study. We used isolated experimental tissue chamber protocol. The sphincteric muscle tissue was placed in the tissue chamber containing Krebs solution, and the degree of contraction was measured as “mg”. We evaluated the effects of drugs in both the baseline and the precontracted states. Results: Tissue relaxation response against nifedipine and glycerol trinitrate in both the baseline and the precontracted states were statistically significant. The relaxation response against nifedipine was higher than the one against glycerol trinitrate; however, it was not statistically significant. Discussion: We showed that both nifedipine and GTN were effective ” in vitro” on muscle tissue relaxation in the organ bath. Both nifedipine and GTN were found to lead to significant reduction of tension at both the baseline and the precontracted states. Their effects were more significant in the precontracted muscle tissue than the tissue with baseline tension. Although clinical studies have revealed controversial results, since we have proven their efficacies “in vitro”, we have the opinion that these two drugs may find more place for themselves in clinical use particularly with the purpose of chemical sphincterotomy, in other words, the relief of sphincter spasm, paying attention to their side effects.