Background: Sensitization of transient receptor potential (TRP) cation channels probably contributes to intestinal hypersensitivity, a hallmark of gastrointestinal disorders. Histamine acting via histamine 1 receptor (H1R) to open TRP cation channels might also be involved.
Method: The enterochromaffin cell line P-STS, responsive to histamine via H1R, was used as model to study possible synergism between histamine and TRP vanilloid 4 (TRPV4) pathways.
Results: The TRPV4 antagonist RN-1734, but not HC-067047, inhibited the cytoplasmic calcium response to histamine in P-STS cells. However, also pre-incubation with the TRPV4 agonist RN-1747 strongly inhibited the calcium response to histamine in P-STS as well as HeLa cells. This inhibitory effect of RN-1747 was not due to its known TRP melastatin 8 (TRPM8) antagonism, as the TRPM8 antagonist RQ-00203078 showed no significant effect on the histamine-induced calcium response of P-STS or HeLa cells.
Conclusion: The TRPV4 agonist RN-1747, and possibly also the structurally similar TRPV4 antagonist RN-1734, should be used with caution because of yet unidentified interference with histamine signaling via H1R.
Keywords: Histamine; Irritable bowel disease; Phenylsulfonamide; RN-1747; Transient receptor potential vanilloid 4.
© 2019 S. Karger AG, Basel.