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Gender Differences in Na/Ca Exchanger Current and β‐Adrenergic Responsiveness in Heart Failure in Pig Myocytes
Author(s) -
WEI SHAOKUI,
MCCURLEY JOHN M.,
HANLON STEPHEN U.,
HAIGNEY MARK C. P.
Publication year - 2007
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1196/annals.1387.026
Subject(s) - medicine , endocrinology , heart failure , myocyte , contractility , basal (medicine) , sodium calcium exchanger , adrenergic , furosemide , cardiology , calcium , receptor , insulin
Clinical trials suggest females experience less heart failure (HF) progression, mortality, and arrhythmia frequency. HF increases Na/Ca exchanger (NCX) expression and activity contributing to both depressed contractility and ventricular arrhythmias, but whether gender modifies this effect is unknown. Left ventricular myocytes were isolated from control and from tachycardic pacing‐induced failing swine hearts of both sexes. The Ni‐sensitive NCX current (I NCX ) was measured in voltage clamp after blocking other channels. In control myocytes there is no difference in basal I NCX and β‐adrenergic responsiveness between male and female animals. HF greatly increased I NCX and reduced β‐adrenergic responsiveness in males compared to females, an effect that was eliminated by PP1. Diuretic therapy (furosemide, 1 mg/kg/day) further enhanced I NCX and reduced β‐adrenergic responsiveness in females and eliminated the gender difference. Gender‐specific differences in calcium handling may contribute to improved survival of females in HF.