Sex differences in the role of transient receptor potential (TRP) channels in endothelium-dependent vasorelaxation in porcine isolated coronary arteries

Abstract

Endothelial and smooth muscle Transient Receptor Potential (TRP) channels contribute to regulation of vascular tone. We have previously reported sex differences in the endothelial function in porcine isolated coronary arteries (PCAs). The present study examined the role of TRP channels in endothelium-dependent and H2O2-induced vasorelaxations in male and female PCAs. Distal PCAs were mounted in a wire myograph and precontracted with U46619. Concentration-response curves to bradykinin, H2O2 and A23187 were constructed in the presence of TRP channel antagonists with or without L-NAME and indomethacin to inhibit NO synthase and cyclooxygenase respectively. 2-APB (TRPC & TRPM antagonist) inhibited the maximum relaxation (Rmax) of the bradykinin-induced vasorelaxation and abolished the EDH-type response in PCAs from both sexes. SKF96365 (TRPC antagonist) inhibited the Rmax of bradykinin-induced vasorelaxation in males, and inhibited Rmax of the EDH-type response in both sexes. Pyr3 (TRPC3 antagonist) inhibited both the NO and EDH components of the bradykinin-induced vasorelaxation in males, but not females. RN1734 (TRPV4 antagonist) reduced the potency of the NO component of the bradykinin-induced vasorelaxation in females only, but inhibited the Rmax of the EDH-type component in both sexes. 2-APB, SKF96365 and RN1734 all reduced the H2O2-induced vasorelaxation, whereas Pyr3 had no effect. No differences in expression level of TRPC3 and TRPV4 between sexes were detected using Western blot. Present study demonstrated a clear sex differences in the role TRP channels where TRPC3 play a role in the NO- and EDH-type response in males and TRPV4 play a role in the NO-mediated response in females.

Keywords: 1-[2-(4-Methoxyphenyl)-2-[3-(4-methoxyphenyl)propoxy]ethyl]imidazole (SKF96365) (PubChem CID: 104955); 2,4-dichloro-N-(propan-2-yl)-N-{2-[(propan-2-yl)amino]ethyl}benzene-1-sulfonamide (RN1734) (PubChem CID: 3601086); 2-[3-(4-pentylphenyl)prop-2-enoylamino]benzoic acid (ACA) (PubChem CID: 1974); 2-di(phenyl)boranyloxyethanamine (2-APB) (PubChem CID: 1598); A23187 (PubChem CID: 11957499); Bradykinin; Bradykinin (PubChem CID: 6026); Endothelium-dependent relaxation; Ethyl 1-[4-(trichloroprop-2-enamido)phenyl]-5-(trifluoromethyl)-1H-pyrazole-4-carboxylate (Pyr3) (PubChem CID: 56964346); Hydrogen peroxide (H(2)O(2)); Hydrogen peroxide (PubChem CID: 784); Indomethacin (PubChem CID: 3715); L-NAME (PubChem CID: 39836); Sex differences; Transient receptor potential canonical type 3 channel (TRPC3); Transient receptor potential vanilloid type 4 channel (TRPV4).