Alpha 1-adrenergic receptors in cardiac ventricles of Dahl rats.
This study was designed to examine the effects of sex, age, and a high-salt diet on cardiac alpha 1-adrenoceptors in an animal model of genetic hypertension, the Dahl salt-sensitive rat. Ventricular alpha 1-adrenoceptors were measured by radioligand binding with [3H]prazosin in membrane fractions in Dahl S and R rats of 7, 12, and 15 weeks of age. In both S and R rats, the maximal binding (Bmax) of alpha 1-adrenoceptor binding was greater in male than in female rats. The Bmax decreased with age in both the S and R strains; at 12 weeks of age, Bmax was approximately one-half of that observed at 7 weeks of age in both S and R strains. In the rats fed a high-salt diet, the Bmax tended to be greater in S rats than in R rats at 12 weeks of age and this difference became significant at 15 weeks of age. A significant positive correlation was found between the Bmax and the heart-to-body weight ratio in the Dahl S and R rats. The dissociation constant (Kd) was not different between male S and R rats at each age. These results suggest that the ventricular alpha 1-adrenoceptor may be involved in cardiac hypertrophy in Dahl rats.
Hayashi
S
S
Second Department of Internal Medicine, Yokohama City University, Japan.
Umemura
S
S
Ashino
K
K
Hirawa
N
N
Toya
Y
Y
Abe
Y
Y
Ishii
M
M
D000375:Aging; D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D005260:Female; D006352:Heart Ventricles / Q000378:metabolism*; D006973:Hypertension / Q000209:etiology / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D011869:Radioligand Assay; D051381:Rats; D018340:Receptors, Adrenergic, alpha-1 / Q000378:metabolism*; D012737:Sex Factors; D012982:Sodium, Dietary
D018340:Receptors, Adrenergic, alpha-1; D012982:Sodium, Dietary