Skeletal muscle arteriolar reactivity in SS.BN13 consomic rats and Dahl salt-sensitive rats.
Previous studies have demonstrated that angiotensin II is a crucial factor in maintaining normal vascular reactivity. In this study, we tested the hypothesis that altered reactivity to vasoactive stimuli in Dahl salt-sensitive (S) rats on a high salt diet could be prevented by introgression of chromosome 13 from the normotensive Brown Norway strain, which carries a normally functioning renin gene. Dahl S and consomic SS.BN13 rats were fed a low salt (0.4%) or high salt diet (4%) for 4 to 6 days or 4 weeks. Arteriolar responses to elevated superfusion solution PO2, acetylcholine, and sodium nitroprusside were assessed by videomicroscopy in the cremaster muscle. Arteriolar dilation to sodium nitroprusside was normal in both strains. Arteriolar constriction to elevated PO2 was enhanced in Dahl S and SS.BN13 rats on a high salt diet compared with responses in rats on a low salt diet. Arterioles of Dahl S rats on a high salt diet had an impaired dilation to acetylcholine, whereas dilator responses to acetylcholine were restored in SS.BN13 rats regardless of elevated salt intake. These data suggest that (1) restitution of normal renin control mechanisms by chromosomal transfer contributes to the recovery of dilator responses in SS.BN13 rats versus Dahl S rats but does not affect constrictor responses to oxygen, and (2) factors in the Dahl S genetic background contribute to an enhanced sensitivity of arterioles to elevated PO2 independent of elevated blood pressure.
Drenjancevic-Peric
Ines
I
Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wis 53226, USA.
Frisbee
Jefferson C
JC
Lombard
Julian H
JH
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001160:Arterioles / Q000187:drug effects / Q000502:physiology*; D005260:Female; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply*; D009599:Nitroprusside / Q000494:pharmacology; D051381:Rats; D011914:Rats, Inbred BN; D020303:Rats, Inbred Dahl; D011919:Rats, Inbred Strains; D017673:Sodium Chloride, Dietary / Q000008:administration & dosage; D014661:Vasoconstriction / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
D017673:Sodium Chloride, Dietary; D014665:Vasodilator Agents; D009599:Nitroprusside; D000109:Acetylcholine