Impaired Chronotropic Response to Exercise in Mice Lacking Catecholamines in Adrenergic Cells

• Published in: Annals of the New York Academy of Sciences 2008-12, Vol.1148 (1), p.297-301
• Main Authors: Bao, Xuping, Liu, Fujun, Gu, Yusu, Lu, Chuanyi M., Ziegler, Michael G.
• Format: Article
• Language: English
• Subjects: Adrenal Glands - chemistry; adrenergic TH-knockout mice; Animals; blood pressure; Blood Pressure - physiology; Brain Chemistry; catecholamine; Catecholamines - metabolism; exercise; Female; heart rate; Heart Rate - physiology; Hemodynamics; Male; Mice; Mice, Knockout; Myocardium - chemistry; phenylethanolamine N-methyltransferase; Phenylethanolamine N-Methyltransferase - genetics; Phenylethanolamine N-Methyltransferase - metabolism; Physical Conditioning, Animal; Telemetry; Tyrosine 3-Monooxygenase - genetics; Tyrosine 3-Monooxygenase - metabolism; tyrosine hydroxylase
• ISSN: 0077-8923; 1749-6632; 1930-6547
• DOI: 10.1196/annals.1410.056

To define the in vivo role of adrenergic catecholamines (CAs), we generated a mouse model whereby tyrosine hydroxylase (TH) was knocked out (KO) in phenylethanolamine N‐methyltransferase–expressing cells. These adrenergic specific TH‐KO mice were viable and grossly normal. Their resting heart rate and blood pressure, as monitored by telemetry, were unchanged. However, when challenged with treadmill exercise, their chronotropic responses were significantly reduced by 14% compared to wild‐type mice. Thus, our data suggest that adrenergic CA is required for normal chronotropic responses to stress, but not required for prenatal and postnatal development or normal cardiovascular function at rest.