title: Impaired chronotropic response to exercise in mice lacking catecholamines in adrenergic cells.
abstract: 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.
authors.affiliation: Department of Medicine, University of California San Diego, San Diego, California 92103-8341, USA. xbao@ucsd.edu
authors.forename: Xuping
authors.initials: X
authors.lastname: Bao
authors.forename: Fujun
authors.initials: F
authors.lastname: Liu
authors.forename: Yusu
authors.initials: Y
authors.lastname: Gu
authors.forename: Chuanyi M
authors.initials: CM
authors.lastname: Lu
authors.forename: Michael G
authors.initials: MG
authors.lastname: Ziegler
mesh_terms: D000311:Adrenal Glands / Q000737:chemistry; D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D001923:Brain Chemistry; D002395:Catecholamines / Q000378:metabolism*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006439:Hemodynamics; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009206:Myocardium / Q000737:chemistry; D010625:Phenylethanolamine N-Methyltransferase / Q000235:genetics / Q000378:metabolism; D010805:Physical Conditioning, Animal; D013686:Telemetry; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics* / Q000378:metabolism
chemical_list: D002395:Catecholamines; D014446:Tyrosine 3-Monooxygenase; D010625:Phenylethanolamine N-Methyltransferase