The Study Of Prostanoid Receptors On Bovine Oviductal Smooth Muscle

Prostaglandins and their receptors play important role in the reproductive system. In this study, the distribution of prostanoid receptors types in bovine oviductal smooth muscle was investigated using mechanical, immunohistochemical and biochemical approaches.First, the effects of prostaglandins (PGE2, PGF2α, PGD2) and receptor selective agonists (Butaprost, U-46619) were examined on the bovine oviductal smooth muscle using Physiological Signals Collection System in vitro. The results showed that PGE2 and Butaprost concentration dependently inhibited tonic and spontaneous contraction of both the ampulla and the isthmus smooth muscle strips; PGF2αinduced significantly contractile response in ampulla and isthmus smooth muscle isolated from bovine oviduct at high concentrations (1μM-10μM); PGD2 inhibited the ampulla smooth muscle contraction at low concentrations, but induced significantly contractile response at high concentrations (1μM–10μM) in the ampulla and isthmus smooth muscle; U-46619 induced potent contractile response in both the ampulla and the isthmus smooth muscle. These results suggest that EP4 or EP2, FP, DP, TP receptors are present in the bovine oviductal smooth muscle.Secondly, immunohistochemical study analysis for immunoreactive cyclooxygenase (COX) in proestrus bovine oviduct indicated that COX-1 was expressed both in epithelial cells and smooth muscle cells, but COX-2 was only predominantly expressed in epithelial cells. On the other hand, real time PCR analysis for relative expression of COX-1 mRNA and COX-2 mRNA was showed expression of COX-1 and COX-2 not significantly differed between isthmus and ampulla of bovine oviduct. These results suggest that COX-1 and COX-2 regulate prostanoid synthesis and play dissimilar physiological roles in bovine oviduct.Thirdly, relative expression of EP2 and EP4 receptors mRNA was analyzed by real time PCR in proestrus bovine oviduct smooth muscle. Results showed although EP2 mRNA was homogeneously expressed in bovine oviduct, but level of EP4 mRNA was significantly higher in the ampulla than that in the isthmus. These results indicate PGE2 play more effectively inhibition to ampulla contractility that compare with isthmus.