Differential involvement of L- and T-type Ca2+ channels, store-operated calcium channel (TRPC) and Rho-kinase signaling pathway(s) in PGF2 α-induced contractions in myometrium of non-pregnant and pregnant buffaloes (Bubalus bubalis)

This study unravels the differential involvement of calcium signaling pathway(s) in PGF2α-induced contractions in myometrium of non-pregnant and pregnant buffaloes. Compared to the myometrium of pregnant animals, myometrium of non-pregnant buffaloes was more sensitive to PGF2α–induced contractile effect as manifested by the changes in mean integral tension (MIT) and tonicity. However, phasic contraction was significantly more in myometrium of pregnant animals. The uterotonic effect of PGF2α was dependent on extracellular Ca2+ and its influx through nifedipine-sensitive L-type Ca2+ channels both in non-pregnant and pregnant animals, but T-type Ca2+ channels play an additional role during pregnancy. Entry of extracellular Ca2+ is triggered by enhanced functional involvement of Pyr3-sensitive TRPC3 channels and Rho-kinase pathways to regulate uterotonic action of PGF2α in myometrium of non-pregnant buffaloes while these are down-regulated during pregnancy as there was significantly reduced expression of Rho-A proteins in myometrium of pregnant buffaloes and down-regulation of these facilitate uterine quiescence. Intracellular Ca2+ plays minor role in myometrium of both the non-pregnant and pregnant buffaloes. Graphical abstract
Source: Prostaglandins and Other Lipid Mediators - Category: Lipidology Source Type: research