Published online Feb 28, 2018. doi: 10.3748/wjg.v24.i8.882
Peer-review started: October 23, 2017
First decision: November 8, 2017
Revised: November 14, 2017
Accepted: November 28, 2017
Article in press: November 28, 2017
Published online: February 28, 2018
Relaxin (RLX) has been reported to modulate gastrointestinal smooth muscle activity in mice through the L-arginine/NO pathway. However, the possibility that the depressant effects of RLX in ileal preparations could involve additional pathways, not fully elucidated yet, was raised. On these grounds, the present study was designed to investigate the signaling pathways involved in the effects of RLX on ileal preparations. To this aim, we performed experiments using a combined mechanical and electrophysiological approach.
The actions of RLX occur through a dual signaling pathway that, from a physiological point of view, might represent a reinforcing and cross-talking mechanism for the hormone aimed to guarantee and to prolong its myorelaxant effects in the small intestine.
This study shows, for the first time in ileal preparations, that RLX is able to influence the smooth muscle mechanical and electrophysiological activity through a dual signaling pathway.
The activation of both adenylate cyclase and guanylate cyclase pathways by RLX underlines the physiological importance of the hormone to relax ileal smooth muscle. In this view, it could be speculated that RLX may represent a potential therapeutic tool in those intestinal dysfunctions characterized by hypermotility states.
The modulation of gastrointestinal smooth muscle activity by hormones may be investigated “in vitro” by recording either the mechanical responses or the electrophysiological properties. In ileal preparations, the hormone RLX has been shown to exert a modulatory role by depressing spontaneous contractions and by influencing the electrophysiological activity.