(085) Montelukast, a LRRC8A Inhibitor Decreases the Contractile Response to Phenylephrine in the Corpus Cavernosum of Diabetic Mice

Abstract

Abstract Introduction Increased reactive oxygen species are often correlated with erectile dysfunction (ED) by enhancing contractility and favoring the flaccid state of the penis (which is mainly mediated by α-adrenergic innervation) and decreasing the relaxation of the corpus cavernosum (CC) associated with decreased nitric oxide (NO) bioavailability. Leucine Rich Repeat Containing 8 (LRRC8) Volume Regulated Anion Channels (VRACs) regulates Nox1 and modulates the extracellular production of superoxide anion (O2•-). Downregulation of LRRC8 is associated with decreased production of O2•- and we have demonstrated improved relaxation and reduced contraction of the pudendal artery in LRRC8A knockout mice. Objective In this study, we aim to test the hypothesis that inhibition of Nox or LRRC8A decreases phenylephrine (PE)-induced contraction in the CC of diabetic mice. Methods To test this hypothesis, the CC of diabetic (dbdb-/-, 16-week-old) mice were mounted in myographs, and the contraction elicited by PE was performed in the absence and repeated in the presence of the LRRC8 inhibitor, montelukast or Nox1/Nox4 inhibitor, GKT137831. The maximal contraction in the absence of the inhibitor was taken as 100%, and the contraction in the presence of the inhibitor was calculated as a percentage of the maximal contraction attained in the absence of the inhibitor. Results Contraction induced by phenylephrine in the CC of diabetic mice (1.27 + 0.2 mN) was similar to that observed in the control mice (1.26 + 0.4 mN). In the presence of the LRRC8 inhibitor, montelukast, PE-induced contraction of the CC was significantly reduced, reaching maximal contraction of 69 + 7% and 65 + 10% in the control and diabetic group, respectively. In the presence of the Nox1/Nox4 inhibitor, GKT137831, the contraction elicited by PE was reduced only in the diabetic group (68 + 9% of the maximal contraction), whereas in the control group this reduction was not significant (82 + 14% of the maximal contraction). Conclusions This is the first study demonstrating that, in the CC, LRRC8 modulates the contractile response induced by α-adrenergic stimulation and this may be associated with O2•- production, which plays a role in the development of ED. Since a great number of diabetic patients are not benefited by phosphodiesterase 5 inhibitors therapy, LRRC8 might be a potential therapeutic target for the development of new drugs to improve sexual function in diabetes. Disclosure No