Effect of dietary salt and cholesterol loading on vascular adrenergic receptors.
To evaluate the effects of salt and cholesterol intake on vascular responses to catecholamines, alpha 1- and beta-adrenergic receptor densities were determined in control, cholesterol-loaded, salt-loaded with desoxycorticosterone acetate (DOCA) and furosemide-loaded male rabbits, using [3H]-prazosin and (-)-[125I]-cyanopindolol as ligands, respectively. In the aortic membrane, the density of alpha 1-adrenergic receptors (Bmax = 120 +/- 14 fmol/mg protein, Kd = 0.48 +/- 0.05 nM) was higher than that of beta-adrenergic receptors (Bmax = 10.5 +/- 1.7 fmol/mg protein, Kd = 47.1 +/- 8.6 pM). Salt loading and depletion did not alter the density or affinity of either the alpha 1- or beta-adrenergic receptors. By contrast, cholesterol loading significantly decreased alpha 1-adrenergic receptor affinity to a Kd value of 0.81 +/- 0.11 nM from the control level of 0.48 +/- 0.05 and increased the beta-adrenergic receptor density to a Bmax of 18.7 +/- 1.9 fmol/mg protein from the control level of 10.5 +/- 1.7. These results showed that the density of alpha 1-adrenergic receptors was higher than that of beta-adrenergic receptors in the rabbit aortic membrane preparation, and suggested that the sensitivity of aortic membrane to catecholamines was changed by cholesterol loading.
Tsutsumi
S
S
Department of Internal Medicine 2, Nagoya University School of Medicine, Japan.
Tsuji
K
K
Ogawa
K
K
Ito
T
T
Satake
T
T
D000818:Animals; D001011:Aorta / Q000378:metabolism*; D001667:Binding, Competitive; D002199:Capillary Permeability / Q000187:drug effects; D002791:Cholesterol, Dietary / Q000008:administration & dosage*; D005665:Furosemide / Q000008:administration & dosage; D008297:Male; D008560:Membrane Fluidity / Q000187:drug effects; D011817:Rabbits; D011869:Radioligand Assay; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects*; D012982:Sodium, Dietary / Q000008:administration & dosage*
D002791:Cholesterol, Dietary; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D012982:Sodium, Dietary; D005665:Furosemide