ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Abstract: The presence of immunoreactive (IR) endothelin (ET)-1 and ET-1 receptors in rat retina has been studied by radioimmunoassay and receptor assay, respectively. The specific binding of 125I-ET-1 to rat retinal particulate preparations was saturable. Apparent equilibrium conditions were established within 120–140 min. Scatchard analysis of binding data indicated a single class of high-affinity binding sites with a KD of 35 ± 11 pM and a Bmax of 168 ± 60 fmol/mg of protein. 125I-ET-1 binding to retinal particulate preparations was not inhibited by 1 μM concentrations of somatostatin, atrial natriuretic factor, brain natriuretic peptide, thyroid-stimulating hormone, growth hormone, or insulin. The three endothelin isoforms, ET-1,-2, and-3, had similar affinity for the receptor. Cross-linking of 125I-ET-1 to retinal particulate preparations with disuccinimidyl suberate resulted in the labeling of two bands with apparent molecular masses of 52 and 34 kDa. We have established a highly sensitive and specific radioimmunoassay for ET-1. The concentration of IR-ET-1 in rat retina was 35 ± 10 fmol/g wet weight. The demonstration of specific high-affinity ETB receptors and the presence of IR-ET-1 suggest that the peptide may act as a neurotransmitter or neuro-modulator in the retina.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1471-4159.1993.tb03627.x
