Myocardial slice: a physiological approach to beta-adrenergic ([3H] CGP-12177) receptor binding in hamster and guinea pig heart.
A new technique is described for the characterization and quantification of beta-adrenergic receptors in biologically viable slices of myocardium from the hamster right ventricle using the hydrophilic radioligand, [3H]CGP-12177 (CGP). Binding was stereospecific, saturable, of high affinity, reversible, displaceable by appropriate drugs, and highly positively correlated with increasing tissue concentrations. Bmax for CGP binding to myocardial slices from 50-day-old male Golden Syrian hamsters was 3.28 +/- 0.15 fmol/mg wet weight, while Kd was 0.21 +/- 0.02 nM. Freezing resulted in a close to 50% loss of receptor number with no apparent change in affinity. The slice preparation may be utilized to detect in vivo changes in myocardial cell surface receptors, as evidenced by the fact that the number of receptors in slices from ischemic guinea pigs was increased (Bmax = 15.5 +/- 1.25 fmol/mg wet wt) compared with sham-operated controls (Bmax = 10.4 +/- 0.38 fmol/mg wet wt). The minimal tissue disruption associated with this procedure, as well as its speed, simplicity, and relatively low cost, suggest that the myocardial slice preparation provides an important methodology for the study of beta-adrenergic receptor binding in the semiintact myocardium.
Watson-Wright
W M
WM
Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada.
Armour
J A
JA
Johnstone
D E
DE
Wilkinson
M
M
D000319:Adrenergic beta-Antagonists / Q000378:metabolism*; D000818:Animals; D003327:Coronary Disease / Q000378:metabolism; D006224:Cricetinae; D005615:Freezing; D006321:Heart / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D008647:Mesocricetus; D009206:Myocardium / Q000378:metabolism*; D011412:Propanolamines / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*
D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D011943:Receptors, Adrenergic, beta; C033394:CGP 12177