title: Cardiac beta-receptor variation in rat strains selectively bred for differences in susceptibility to stress.
abstract: The radioligand 3H-DHA was used to estimate the density and affinity of cardiac beta-receptors in rat strains selectively bred for differences in response to stress. Maudsley Reactive rats selected for heightened reactivity to stress had a greater density of beta-adrenergic binding in cardiac membranes than rats of two genetically distinct Maudsley Non-Reactive strains selected for decreased reactivity to stress, and compared with one of these Non-Reactive strains the MNR/Har, increased affinity for 3H-DHA. Together with previous findings the present results demonstrate a negative correlation between estimates of basal sympathetic activity on the on hand, and post-synaptic beta-receptors in heart on the other, that are consistent with the notion that these receptor alterations have occurred as a result of long-term differences in pre-synaptic release of transmitter. The Maudsley strains may, therefore, provide a useful model for the study of beta-adrenergic receptors as a physiological locus for regulation of end-target responsiveness to sympathetic stimulation.
mesh_terms: D000818:Animals; D004082:Dihydroalprenolol / Q000378:metabolism; D008297:Male; D009206:Myocardium / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains; D011941:Receptors, Adrenergic / Q000032:analysis*; D011943:Receptors, Adrenergic, beta / Q000032:analysis*; D013312:Stress, Physiological / Q000378:metabolism*; D013564:Sympathetic Nervous System / Q000503:physiopathology
chemical_list: D011941:Receptors, Adrenergic; D011943:Receptors, Adrenergic, beta; D004082:Dihydroalprenolol