Inhibition of the adenosine2A receptor-epoxyeicosatrienoic acid pathway renders Dahl salt-resistant rats hypertensive

Hypertension. 2009 Dec;54(6):1284-90. doi: 10.1161/HYPERTENSIONAHA.108.123570. Epub 2009 Oct 12.

Abstract

Adenosine-induced renovasodilation in Dahl rats is mediated via activation of adenosine(2A) receptors (A(2A)Rs) and stimulation of epoxyeicosatrienoic acid (EET) synthesis. Unlike Dahl salt-resistant rats, salt-sensitive rats exhibit an inability to upregulate the A(2A)R-EET pathway with salt loading; therefore, we examined the effect of in vivo inhibition of the A(2A)R-EET pathway on blood pressure and the natriuretic response to salt-loading in Dahl salt-resistant rats. N-Methylsulfonyl-6-(2-propargyloxyphenyl)hexanamide (MS-PPOH; 20 mg/kg per day), an epoxygenase inhibitor, or ZM241385 (ZM; 5 mg/kg per day), an A(2A)R antagonist, was given daily as an IV bolus dose for 3 days before and after placing rats on high salt intake (2% saline). After 3 days of high salt, systolic blood pressure per 24 hours increased from 108+/-2 mm Hg to 136+/-5 mm Hg and 140+/-4 mm Hg when treated with MS-PPOH or ZM, respectively (P<0.001). Plasma levels of EETs and dihydroxyeicosatrienoic acids during salt loading and MS-PPOH (29.3+/-1.8 ng/mL) or ZM treatment (9.8+/-0.5 ng/mL) did not increase to the same extent as in vehicle-treated rats (59.4+/-1.7 ng/mL; P<0.001), and renal levels of EETs+dihydroxyeicosatrienoic acids were 2-fold lower with MS-PPOH or ZM treatment. On day 3 of the high salt intake, MS-PPOH- and ZM-treated rats exhibited a positive Na(+) balance, and plasma Na(+) levels were significantly increased (163.3+/-1.2 and 158.1+/-4.5 mEq/L, respectively) compared with vehicle-treated rats (142.1+/-1 mEq/L), reflecting a diminished natriuretic capacity. These data support a role for the A(2A)R-EET pathway in the adaptive natriuretic response to modulate blood pressure during salt loading.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenergic alpha-2 Receptor Antagonists*
  • Amides / pharmacology*
  • Animals
  • Blood Pressure / drug effects
  • Blood Pressure / physiology
  • Drinking / physiology
  • Eicosanoids / antagonists & inhibitors
  • Eicosanoids / metabolism*
  • Hydroxyeicosatetraenoic Acids / blood
  • Hypertension, Renal / chemically induced
  • Hypertension, Renal / metabolism*
  • Male
  • Natriuresis / drug effects
  • Natriuresis / physiology
  • Oxidoreductases / antagonists & inhibitors
  • Oxidoreductases / metabolism
  • Rats
  • Rats, Inbred Dahl
  • Receptors, Adrenergic, alpha-2 / metabolism*
  • Sodium Chloride, Dietary / pharmacology
  • Triazines / pharmacology
  • Triazoles / pharmacology

Substances

  • Adrenergic alpha-2 Receptor Antagonists
  • Amides
  • Eicosanoids
  • Hydroxyeicosatetraenoic Acids
  • N-methylsulfonyl-6-(2-propargyloxyphenyl)hexanamide
  • Receptors, Adrenergic, alpha-2
  • Sodium Chloride, Dietary
  • Triazines
  • Triazoles
  • ZM 241385
  • 20-hydroxy-5,8,11,14-eicosatetraenoic acid
  • Oxidoreductases