Gender differences in Na/Ca exchanger current and beta-adrenergic responsiveness in heart failure in pig myocytes.
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 beta-adrenergic responsiveness between male and female animals. HF greatly increased I(NCX) and reduced beta-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 beta-adrenergic responsiveness in females and eliminated the gender difference. Gender-specific differences in calcium handling may contribute to improved survival of females in HF.
Wei
Shao-Kui
SK
Division of Cardiology, Department of Medicine, Uniformed Services University of the Health Sciences, A3060, USUHS, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
McCurley
John M
JM
Hanlon
Stephen U
SU
Haigney
Mark C P
MC
D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D002303:Cardiac Output, Low / Q000503:physiopathology*; D002478:Cells, Cultured; D005260:Female; D005665:Furosemide / Q000494:pharmacology; D006352:Heart Ventricles / Q000166:cytology; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism*; D012737:Sex Factors; D019831:Sodium-Calcium Exchanger / Q000502:physiology*; D013552:Swine; D016276:Ventricular Function
D000318:Adrenergic beta-Agonists; D011943:Receptors, Adrenergic, beta; D019831:Sodium-Calcium Exchanger; D005665:Furosemide; D007545:Isoproterenol