HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Martínez-Nieves, B. Articles by Dunbar, J. C. Search for Related Content PubMed PubMed Citation Articles by Martínez-Nieves, B. Articles by Dunbar, J. C.

---

Original Article

Vascular Dilatatory Responses to Sodium Nitroprusside (SNP) and -Adrenergic Antagonism in Female and Male Normal and Diabetic Rats

Department of Physiology, Wayne State University, School of Medicine, Detroit, Michigan 48201

Diabetes is associated with impaired vascular dilatatory responses that appear to be influenced by sex as well as diabetic state. Therefore, we hypothesized that vascular and sympathetic control function exhibit a greater deterioration following the induction of diabetes in female than in male rats. We conducted a comparative determination of the effect of sodium nitroprusside (SNP, a nitrous oxide donor) and that of an ₁-adrenergic antagonist, prazosin, on selective vascular flows, mean arterial pressure (MAP), and heart rate (HR), in female and male normal and diabetic rats. Rats were made diabetic using streptozotocin (50 mg/kg, iv) and maintained for 5–6 weeks. Following anesthesia with urethane/-chloralose, the femoral artery and vein were cannulated for recording and sampling. Flow probes were placed on the iliac, renal, and superior mesenteric arteries. SNP (1, 5, 10, and 20 µg/kg) infusions resulted in a dose-dependent decrease in MAP in normal and diabetic rats. The decrease in MAP in normal males was 37% less at the 20 µg/kg concentration of SNP when compared to normal females. The HR was not significantly changed in response to the hypotensive effect of SNP; however, reflex tachycardia was more prominent in diabetic males. The vascular conductance (flow/MAP) was increased by SNP in normal and diabetic rats in a dose-dependent fashion; however, the responsiveness was decreased in the iliac and superior mesenteric and increased in the renal arteries in diabetics when compared to normals. Diabetic males were 42% and 28% less responsive to SNP in the iliac and superior mesenteric arteries, respectively. On the other hand, diabetic females were 1.5-fold more responsive in the renal artery when compared to normals. Prazosin (4 mg/kg) decreased the MAP in normal and diabetic rats to a comparable degree. Prazosin increased the vascular conductance in all three vascular beds in normal and diabetic rats with the greater increase occurring in the iliac (118%) and superior mesenteric (110%) arteries. We concluded that diabetes is associated with an increased response to NO in the renal vessels and a decreased response in the iliac and superior mesenteric vessels in both females and males. -Adrenergic tone was greatest in diabetic female and male rats. This study suggests that decreased vascular flow in diabetes is a result of a combination of decreased sensitivity to NO and increased adrenergic tone.

This article has been cited by other articles:

				E. Sanz, N. Fernandez, L. Monge, B. Climent, G. Dieguez, and A. L. Garcia-Villalon Relaxation by urocortin of rat renal arteries: effects of diabetes in males and females Cardiovasc Res, June 1, 2003; 58(3): 706 - 711. [Abstract] [Full Text] [PDF]

				B. Martínez-Nieves and J. C. Dunbar The Effect of Diabetes and Sex on Nitric Oxide-Mediated Cardiovascular Dynamics Experimental Biology and Medicine, January 1, 2001; 226(1): 37 - 42. [Abstract] [Full Text]