Brain binding sites for atrial natriuretic factor (ANF): alterations in prehypertensive Dahl salt-sensitive (S/JR) rats.
The binding of radioiodinated atrial natriuretic factor (125I-ANF-28) to discrete areas of brain in 7 week old, inbred Dahl salt-sensitive (S/JR) and salt-resistant (R/JR) rats was studied utilizing quantitative film autoradiography. At this age, S/JR rats exhibit systolic blood pressures that are prehypertensive and tend to be slightly higher than systolic blood pressures of age-matched R/JR rats. Scatchard analysis of 125I-ANF-28 binding in forebrain revealed that S/JR rats have a significantly increased number of binding sites for 125I-ANF-28 in the subfornical organ as compared to R/JR controls. In contrast, values for 125I-ANF-28 binding capacity in the choroid plexus and area postrema were similar for both strains, and binding affinity constants for 125I-ANF-28 binding revealed no strain differences in any brain area examined. The elevation in the number of binding sites for atrial natriuretic factor may serve as a compensatory mechanism acting in part to lower fluid volume and sodium levels prior to the precipitous increase in blood pressure which occurs in S/JR rats by 10 weeks of age.
Stewart
R E
RE
Department of Psychology, University of Virginia, Charlottesville 22903.
Swithers
S E
SE
McCarty
R
R
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D001345:Autoradiography; D001921:Brain / Q000378:metabolism*; D004195:Disease Models, Animal; D006973:Hypertension / Q000378:metabolism*; D007457:Iodine Radioisotopes; D007700:Kinetics; D008297:Male; D009928:Organ Specificity; D051381:Rats; D011919:Rats, Inbred Strains; D017461:Receptors, Atrial Natriuretic Factor; D011956:Receptors, Cell Surface / Q000378:metabolism*
D007457:Iodine Radioisotopes; D011956:Receptors, Cell Surface; D009320:Atrial Natriuretic Factor; D017461:Receptors, Atrial Natriuretic Factor