Localization and role of endothelin-1 and endothelin receptors in the human Fallopian tube.
The present experiments were designed to investigate the localization and role of endothelin-1 (ET-1) and endothelin receptors (ET(A) and ET(B)) in human Fallopian tubes obtained from patients in the follicular phase. Immunohistochemical studies revealed the predominant localization of ET-1 and of ET(B) receptors in the tubal epithelium and also within the muscle layer to a lesser degree. ET(A) receptors were dominant within the muscle layer. Scatchard plot analysis of the [(125)I]ET-1 binding also revealed the localization of ET(A) and ET(B) receptors on the Fallopian tubal membrane. A dissociation equilibrium constant of 34.6 +/- 3.3 pmol/l and a maximum binding site concentration of 1137.0 +/- 239.1 fmol/mg protein were obtained from the Scatchard plot analysis. Treatment of Fallopian tubal strips with ET-1 produced a tonic contraction which was inhibited by an ET(A) antagonist but not by an ET(B) antagonist. However, the increase in frequency and decrease in amplitude of rhythmic contractions caused by ET-1 were modulated by the ET(B) antagonist but remained unaffected by the ET(A) antagonist. These results suggest that ET-1 modulates the motility of the Fallopian tube through excitation of ET(A) and/or ET(B) receptors and possibly plays some role in oocyte capture.
Sakamoto
M
M
Department of Comprehensive Reproductive Medicine, Graduate School, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8519, Japan. m.sakamoto.gyne@tmd.ac.jp
Sakamoto
S
S
Kubota
T
T
Aso
T
T
Azuma
H
H
D000328:Adult; D001696:Biomechanical Phenomena; D019332:Endothelin-1 / Q000502:physiology*; D005187:Fallopian Tubes / Q000502:physiology*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes / Q000378:metabolism; D008875:Middle Aged; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin / Q000502:physiology*
D019332:Endothelin-1; D007457:Iodine Radioisotopes; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin