Binding characteristics of endothelin ET(A) receptors in normal and post-mortem rat lung.
In control lung homogenates, optimal specific binding of [(125)I]endothelin-1 and minimal filter binding was achieved using 50 microg/ml bacitracin, 30 microM phenylmethylsulphonyl fluoride (PMSF) and 10 mM EDTA. In post-mortem tissue (8, 16, and 32 h), no significant changes were seen in ET(A) receptor affinity (K(d)) or number (B(max)): control and 32 h K(d) = 309 +/- 75, 225 +/- 32 pM and B(max) = 173 +/- 42, 185 +/- 17 fmol/mg protein, respectively. Autoradiographic binding sites for [(125)I]endothelin-1 were densely expressed on bronchiolar smooth muscle and parenchyma with moderate binding on epithelium and blood vessels. Histologic sections of post-mortem lung showed minimal deterioration of structures expressing ET(A) binding sites. Hence the ET(A) receptor is stable in the rat lung for up to 32 h post-mortem.
Dias
L S
LS
School of Physiology and Pharmacology, University of New South Wales, 2052, Sydney NSW, Australia.
Schell
D N
DN
Burcher
E
E
D000818:Animals; D001344:Autopsy; D001345:Autoradiography; D019332:Endothelin-1 / Q000378:metabolism; D008168:Lung / Q000033:anatomy & histology / Q000378:metabolism*; D008297:Male; D011485:Protein Binding; D051381:Rats; D017208:Rats, Wistar; D044022:Receptor, Endothelin A; D017466:Receptors, Endothelin / Q000378:metabolism*; D013997:Time Factors
D019332:Endothelin-1; D044022:Receptor, Endothelin A; D017466:Receptors, Endothelin