1. [Disruption of the D(2) dopamine receptor produces adrenergic and endothelin B receptor-dependent hypertension].
- Author
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Li X, Bek M, Asico LD, Yang Z, Rubinstein M, Grandy DK, Goldstein DS, Eisner GM, and Jose PA
- Subjects
- Animals, Gene Deletion, Hypertension genetics, Mice, Mice, Inbred C57BL, Mice, Knockout, Receptor, Endothelin B, Receptors, Dopamine D2 genetics, Hypertension metabolism, Receptors, Adrenergic, beta metabolism, Receptors, Dopamine D2 deficiency, Receptors, Endothelin metabolism
- Abstract
Objective: To assess whether D(2) receptors participate in the regulation of genetic hypertension., Methods: Arterial pressure was measured in mice mutant for the D(2) dopamine receptors, and the interactions between D(2) dopamine receptors and other vasopressor systems were also studied., Results: Both systolic blood pressure (BP) in D(2) mutant (D(2)-/-) and hybrid (D(2)+/-) mice (128 +/- 2 mm Hg, 129 +/- 4 mm Hg) and diastolic BP (107 +/- 2 mm Hg, 108 +/- 3 mm Hg) were higher than in wild-type (D(2)+/+) mice (104 +/- 2 mm Hg, 77 +/- 1 mm Hg). The BP after alpha-adrenergic blockade decreased to a greater extent in D(2)-/- than in D(2)+/+ mice. Epinephrine excretion was greater in D(2)-/- than in D(2)+/+ mice and adrenalectomy decreased blood pressure to a greater extent in D(2)-/- than in D(2)+/+ mice. The non specific endothelin B (ETB) blocker (BQ788) decreased BP in D(2)-/- but had not in D(2)+/+ mice. The ETB1 blocker RES 701 - 1 increased BP in D(2)-/- but not D(2)+/+ mice. ET-1 and the ETB agonist, sarafatoxin S6c increased BP to a greater extent in D(2)+/+ than in D(2)-/- mice. Circulating ET-like immunoreactive peptides were similar in D(2)-/- and D(2)+/+ mice but ETB receptor expression was greater in D(2)-/- than in D(2)+/+ mice. In contrast, blockade of ETA and V(1) vasopressin receptors had no effect on BP in either D(2)-/- and D(2)+/+ mice. The hypotensive effect of the AT(1) antagonist, losartan, was also similar in D(2)-/- and D(2)+/+ mice. The greater basal sodium excretion and lower renal Na(+)/K(+)ATPase activity in D(2)-/- than in D(2)+/+ mice indicate that sodium retention was not the cause of hypertension in these animals., Conclusion: Hypertension in the D(2) mutant mice may be caused by absent inhibitory effect of D(2) receptors on sympathetic outflow coupled with increased ETB2 activity.
- Published
- 2002