CGRP and Visceral Pain: The Role of Sex Hormones in In Vitro Experiment

A large number of studies have showed that women reported feeling pain more acutely than men. In support of this hypothesis, many research groups proved that in different animals model of pain the sex hormones regulate the somatic and visceral sensitivity to different noxious stimuli. Therefore, in this study, we went to evaluate if estrogen hormones by regulating the CGRP levels are implicated during the visceral pain transmission. Toward this aim, we have investigated the effect of 17-estradiol in regulating the synthesis and release of CGRP, as well as the expression levels of the opioid receptor of type K. In order to gain information about the potential effects of 17-estradiol on K-opioid receptor expression and activity, we have cultured F11 cells. Our results revealed that, when F11 cells were short-term exposed (30min) to 17-estradiol, the expression of the opioid K receptor was not significantly modified. We carried out enzyme immunoassay analysis to evaluate the potential effects of short-term exposure to 17-estradiol (30min) on the release of CGRP in F11 cells. The results obtained showed that 17-estradiol at the dose of 100nM is able to induce the release of CGRP from F11 cells; whereas, a higher dose of 17-estradiol (200nM) did not produce significant effects when compared to control. In conclusion, all these findings suggest that the 17-estradiol-regulated release of CGRP could at least in part provide a rational explanation for the difference of gender in the visceral pain sensitivity. J. Cell. Biochem. 118: 510-517, 2017. (c) 2016 Wiley Periodicals, Inc.