Functional endothelin/sarafotoxin receptors in the rat uterus

• Published in: Biochemical and biophysical research communications Vol. 162; no. 3; pp. 952 - 957
• Main Authors: Bousso-Mittler, D., Kloog, Y., Wollberg, Z., Bdolah, A., Kochva, E., Sokolovsky, M.
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 15.08.1989; Elsevier
• Subjects: Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Cell Membrane - metabolism; endothelin; Endothelins; Female; Fundamental and applied biological sciences. Psychology; In Vitro Techniques; Kinetics; Peptides - metabolism; Peptides - pharmacology; Phosphatidylinositols - metabolism; Protein hormones. Growth factors. Cytokines; Proteins; Rats; Receptors, Cell Surface - metabolism; Receptors, Cholinergic - metabolism; Receptors, Endothelin; Receptors, Peptide; sarafotoxin; Uterine Contraction - drug effects; Uterus - metabolism; Viper Venoms - metabolism; Viper Venoms - pharmacology; Ligand binding; Saturation curve; Endothelin; Radiolabelling; Peptides; Rat; Rodentia; Muscle contraction; Dose activity relation; Protein hormone; Vertebrata; Membrane receptor; Mammalia; Uterus; Female genital system; Biological receptor
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/0006-291X(89)90765-1

Functional receptors for the peptides of the endothelin (ET) and sarafotoxin (SRTX) families were detected in the rat uterus. These receptors specifically bind 125I-SRTX-b (B max = 220 fmol/mg protein), as well as ET-1, ET-3 and SRTX-c (IC50's 10, 5, 300 and 780 nM, respectively). Activation of the uterine ET/SRTX receptors induced dose-dependent phosphoinositide (PI) hydrolysis and three typical contractile responses: 1) increase in the muscle tonic tension; 2) increase in frequency of the spontaneous rhythmic contractions; 3) decrease of relaxation in each spontaneous rhythmic cycle. All three effects appeared at doses as low as 0.5–1 nM. Dose responses yield ED50 values of 5.5, 30 and 680 nM for ET-1, SRTX-b and ET-3, respectively. SRTX-c was the least effective peptide in achieving decrease in relaxation. In view of these results, and since the uterine responses to the peptides were almost immediate and reversible, we suggest that the functional ET/SRTX receptor of the rat uterus that is coupled to PI hydrolysis may be of physiological significance.