Vascular responses to alpha-adrenergic stimulation and depolarization are enhanced in insulin-resistant and diabetic Psammomys obesus.
Since vascular complications often accompany diabetes, we examined the influence of the endothelial lining on vascular reactivity in Psammomys obesus, a desert gerbil that acquires insulin resistance and diabetes when exposed to a laboratory diet. Vasoconstriction to phenylephrine and depolarizing KCl, as well as carbachol endothelium-dependent relaxation, were assessed in rings of thoracic aortae obtained from three groups: (i) group A, normoglycemic-normoinsulinemic; (ii) group B, normoglycemic-hyperinsulinemic, and (iii) group C, hyperglycemic-hyperinsulinemic animals. As expected, marked hypertriglyceridemia and hypercholesterolemia characterized groups B and C, which developed enhanced contractile responsiveness to phenylephrine and KCl compared with controls (group A). Furthermore, both experimental groups displayed a significant decrease in endothelium-dependent relaxation to carbachol. Altered lipid profiles are considered to play some role in the observed modification of aortic reactivity. Overall, our data indicate that vascular contractile responsiveness is enhanced early in the development of insulin resistance and diabetes in the female P. obesus.
Zoltowska
M
M
Research Centre, Hôpital Sainte-Justine, Department of Biochemistry, University of Montreal, Montreal, QC H3T 1C5, Canada.
St-Louis
J
J
Ziv
E
E
Sicotte
B
B
Delvin
E E
EE
Levy
E
E
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000502:physiology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology; D005260:Female; D005849:Gerbillinae; D006943:Hyperglycemia / Q000503:physiopathology*; D006946:Hyperinsulinism / Q000503:physiopathology*; D066298:In Vitro Techniques; D007333:Insulin Resistance / Q000502:physiology*; D014661:Vasoconstriction / Q000187:drug effects* / Q000502:physiology
D000316:Adrenergic alpha-Agonists