Influence of high dietary sodium intake on the functional subtypes of alpha-adrenoceptors in the renal cortical vasculature of Wistar-Kyoto rats.
1 Increased renal vascular resistance is one renal functional abnormality that contributes to hypertension, and alpha(1)-adrenoceptors play a pivotal role in modulating this renal vascular resistance. This study investigates the functional contribution of alpha(1)-adrenoceptor subtypes in the renal cortical vasculature of Wistar-Kyoto rats on a normal sodium diet (WKYNNa) compared with those given saline to drink for 6 weeks (WKYHNa). 2 The renal cortical vascular responses to the adrenergic agonists noradrenaline (NA), methoxamine (ME) and phenylephrine (PE) were measured in WKYHNa and WKYNNa rats either in the absence (the control phase) or presence of chloroethylclonidine (CEC), an alpha(1B)-adrenoceptor antagonist, 5-methylurapidil (5-MeU), an alpha(1A) antagonist, or BMY7378, an alpha(1D) antagonist. 3 Results showed a greater renal cortical vascular sensitivity to NA, PE and ME in the WKYHNa compared with WKYNNa rats (P < 0.05). Moreover, 5-MeU and BMY7378 attenuated adrenergically induced renal cortical vasoconstriction in WKYHNa and WKYNNa rats; this response was largely blunted in CEC-treated WKYHNa rats (all P < 0.05) but not in CEC-treated WKYNNa rats. 4 The data suggest that irrespective of dietary sodium content, in Wistar-Kyoto rats alpha(1A)- and alpha(1D)-subtypes are the major alpha(1)-adrenoceptors in renal cortical vasculature; however, there appears to be a functional involvement of alpha(1B)-adrenoceptors in the WKYHNa rats.
Kazi
R N
RN
University Sains Malaysia, Penang, Malaysia.
Munavvar
A S
AS
Abdullah
N A
NA
Khan
A H
AH
Johns
E J
EJ
D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D003000:Clonidine / Q000031:analogs & derivatives / Q000494:pharmacology; D004326:Drinking / Q000187:drug effects; D006898:Hydroxylamines / Q000494:pharmacology; D007672:Kidney Cortex / Q000098:blood supply* / Q000187:drug effects*; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D051381:Rats; D011921:Rats, Inbred WKY; D018340:Receptors, Adrenergic, alpha-1 / Q000187:drug effects* / Q000502:physiology*; D012079:Renal Circulation / Q000187:drug effects / Q000502:physiology; D012964:Sodium / Q000652:urine; D012982:Sodium, Dietary / Q000008:administration & dosage* / Q000494:pharmacology*; D014556:Urine; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology*; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists; D006898:Hydroxylamines; D010879:Piperazines; D018340:Receptors, Adrenergic, alpha-1; D012982:Sodium, Dietary; D014662:Vasoconstrictor Agents; C057446:5-methylurapidil; D010656:Phenylephrine; C051731:chlorethylclonidine; D012964:Sodium; C005214:methoxyamine; C053428:BMY 7378; D003000:Clonidine; D009638:Norepinephrine