These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Characterization of functional endothelin receptors in the porcine myometrium.
    Author: Isaka M, Takaoka K, Yamada Y, Abe Y, Kitazawa T, Taneike T.
    Journal: Peptides; 2000 Apr; 21(4):543-51. PubMed ID: 10822110.
    Abstract:
    To characterize the endothelin (ET) receptor that mediates the contraction induced by ET-1 in the porcine myometrium, we carried out a contraction study, radioligand binding study and molecular study (reverse transcription polymerase chain reaction) for detection of ET receptor-coding genes (mRNA). ET-1 (1 nM-1 microM) caused a tetrodotoxin-insensitive contraction in both longitudinal and circular muscles, but the longitudinal muscle was more sensitive to ET-1 than was the circular muscle. On the other hand, ET-3 and sarafotoxin S6c were less effective to cause a contractile response. The contraction induced by ET-1 was markedly inhibited by BQ123 and FR139317, but BQ788 only slightly inhibited the response induced by ET-1. The radioligand binding study indicated the presence of a single class of 125I-ET-1 binding sites with the same Kd value in both muscle layers. However, Bmax in the longitudinal muscle (3252 fmol/mg protein) was significantly higher than that in the circular muscle (1883 fmol/mg protein). ET-1 and FR139317 inhibited the specific 125I-ET-1 binding completely, but ET-3, sarafotoxin S6c and BQ3020 only slightly inhibited the specific binding (inhibition, 10-20%), suggesting that ET(A) is the dominant ET receptor subtype in the porcine myometrium. The results of the molecular study indicated the expression of both ET(A) and ET(B) receptor-coding genes in the porcine myometrium. In conclusion, ET-1 causes contraction of the porcine myometrium through activation of the ET(A) receptor present on smooth muscle cells. There is a marked muscle layer-related difference (longitudinal muscle > circular muscle) in the ET-1-induced contraction and the ET(A) receptor concentration.
    [Abstract] [Full Text] [Related] [New Search]