Acta Pharmacologica Sinica 2008 May; 29 (5): 564-572; doi: 10.1111/j.1745-7254.2008.00788.x

Aim: This study investigates the subtypes of the α₁-adrenoceptor mediating the adrenergically-induced renal vasoconstrictor responses in streptozotocin-induced diabetic and non-diabetic 2-kidney one clip (2K1C) Goldblatt hypertensive rats.

Methods: The renal blood flow responses to renal nerve stimulation, noradrenaline, phenylephrine, and methoxamine were measured in the absence and presence of nitrendipine, 5-methylurapidil, chloroethylclonidine and BMY 7378.

Results: The renal vasoconstrictor responses were markedly attenuated by nitrendipine and 5-methylurapidil in the diabetic rats (all P<0.05). In the non-diabetic rats, these responses were markedly attenuated by nitrendipine, 5-methylurapidil, and BMY 7378 (all P<0.05). In both experimental groups, chloroethylclonidine markedly accentuated the renal vasoconstrictions caused by all the adrenergic stimuli (all P<0.05).

Conclusion: These observations indicate that α_1A-adrenoceptor subtypes play a major role in mediating adrenergically-induced renal vasoconstriction in the diabetic 2K1C Goldblatt hypertensive rats. In the non-diabetic 2K1C Goldblatt hypertensive rats, contributions of α_1A and α_1D-adrenoceptor subtypes were proposed. Apart from post-synaptic α₁-adrenoceptors, both in the diabetic and non-diabetic 2K1C Goldblatt hypertensive rats, the potential involvement of presynaptic α₁-adrenoceptors is also suggested.

Keywords: renovascular hypertension; 2-kidney one clip Goldblatt hypertensive rats; hypertension; diabetes; kidney