The contribution of adrenoceptor subtype(s) in the renal vasculature of diabetic spontaneously hypertensive rats

Abstract

1 Diabetes and hypertension are both associated with an increased risk of renal disease and are associated with neuropathies, which can cause defective autonomic control of major organs including the kidney. This study aimed to examine the a 1 -adrenoceptor subtype(s) involved in mediating adrenergically induced renal vasoconstriction in a rat model of diabetes and hypertension. 2 Male spontaneously hypertensive rats (SHR), 220-280 g, were anaesthetized with sodium pentobarbitone 7-day poststreptozotocin (55 mg kg À1 i.p.) treatment. The reductions in renal blood flow (RBF) induced by increasing frequencies of electrical renal nerve stimulation (RNS), close intrarenal bolus doses of noradrenaline (NA), phenylephrine (PE) or methoxamine were determined before and after administration of nitrendipine (Nit), 5-methylurapidil (5-MeU), chloroethylclonidine (CEC) and BMY 7378. 3 In the nondiabetic SHR group, mean arterial pressure (MAP) was 14676 mmHg, RBF was 28.071.4 ml min À1 kg À1 and blood glucose was 112.374.7 mg dl À1, and in the diabetic SHR Group, MAP was 14473 mmHg, RBF 26.971.3 ml À1 min kg À1 and blood glucose 316.2710.5 mg dl À1. Nit, 5-MeU and BMY 7378 blunted all the adrenergically induced renal vasoconstrictor responses in SHR and diabetic SHR by 25-35% (all Po0.05), but in diabetic rats the responses induced by RNS and NA treated with 5-MeU were not changed. By contrast, during the administration of CEC, vasoconstrictor responses to all agonists were enhanced by 20-25% (all Po0.05) in both the SHR and diabetic SHR. 4 These findings suggest that a 1A and a 1D -adrenoceptor subtypes contribute in mediating the adrenergically induced constriction of the renal vasculature in both the SHR and diabetic SHR. There was also an indication of a greater contribution of presynaptic adrenoceptors, that is, a 1B -, and/or a 2 -subtypes.

Diuretic action of exogenous hydrogen sulfide in spontaneously hypertensive diabetic rats

“…The observed polyuria and polydipsia in the present study were in agreement with several other studies and that in our laboratory [18]. These findings can be explained on the basis of hyperglycemia, defective reabsorption of glucose by proximal renal tubules, glucosuria and increase in the osmotic pressure that resulted in increased urine production.…”

Effect of the Two New Calcium Channel Blockers Mebudipine and Dibudipine in Comparison to Nifedipine on Vascular Flow of Isolated Rat Kidney

“…Activation of α 1A -adrenoceptors cause constriction of renal vascular resistance bed. L-type Ca 2+ channels appear to be coupled to α 1A -adrenoceptors and are opened when the receptor is activated [17] -entry pathways [18].…”

Effect of TGF-β1 antisense oligodeoxynucleotide on renal function in chronic renal failure rats

“…Acute study After tracheostomy, the left jugular vein and carotid artery were cannulated for continuous infusion of anesthesia (12.5 mg·kg -1 ·h -1 at 3 mL/h in 140 mmol/L NaCl) and the measurement of blood pressure, respectively [15][16][17] . The left femoral artery was cannulated for blood collection.…”