Validation of the polyethylene glycol precipitation technique for the characterization of rat ventricular beta-adrenoceptors.
The use of polyethylene glycol (PEG) to separate [125I]cyanopindolol bound to rat ventricular membranes from free ligand in the characterization of beta-adrenoceptors was compared with the more frequently utilized filtration technique through GF/F glass-fiber filters. The results obtained in tissue from 14 rats demonstrated the following: (i) no significant difference between the two methods for the density of beta-adrenoceptors in ventricular tissue (PEG: 30.9 +/- 1.5 vs GF/F: 28.6 +/- 2.0 fmol/mg of protein); (ii) no significant difference for the dissociation constant (PEG: 70.7 +/- 5.3 vs GF/F: 57.7 +/- 7.7 pM); (iii) similar values for the Hill coefficient (PEG: 0.996 +/- 0.004 vs GF/F: 0.988 +/- .016); (iv) a significant difference for the relationship of bound/free vs bound, expressed as r2 (PEG: 0.82 +/- 0.03 vs GF/F: 0.74 +/- 0.03 P less than 0.05). The apparently greater accuracy of the PEG method over the filtration technique is probably explained by a lower degree of nonspecific binding observed with this method than with the filtration technique. In conclusion, the PEG precipitation method is an interesting and accurate alternative to the more standard filtration technique in ventricular beta-adrenoceptor characterization.
Plourde
G
G
CHUL Research Center, Laval University Medical Center, Ste-Foy, Quebec, Canada.
Lavoie
J P
JP
Rousseau-Migneron
S
S
Nadeau
A
A
D000818:Animals; D011232:Chemical Precipitation; D005374:Filtration; D006352:Heart Ventricles / Q000737:chemistry*; D008297:Male; D008722:Methods; D011092:Polyethylene Glycols; D051381:Rats; D011919:Rats, Inbred Strains; D011943:Receptors, Adrenergic, beta / Q000032:analysis*
D011943:Receptors, Adrenergic, beta; D011092:Polyethylene Glycols