Regulation of myocardial betaARK1 expression in catecholamine-induced cardiac hypertrophy in transgenic mice overexpressing alpha1B-adrenergic receptors.

Published

Journal Article

OBJECTIVES: Using a transgenic mouse model of myocardial-targeted overexpression of the wild-type alpha1B adrenergic receptor (AR) (Tg alpha43), we studied the role of the betaAR kinase (betaARK1) in the evolution of myocardial hypertrophy and its transition to heart failure (HF). BACKGROUND: Increased myocardial expression of betaARK1 has been shown to be associated with HF and certain models of hypertrophy. METHODS: Tg alpha43 mice and their nontransgenic littermate controls were treated with the alpha1AR agonist phenylephrine (PE) for 3, 7 or 14 days to characterize the cardiac consequences. RESULTS: Nontransgenic littermate control mice treated for 14 days with PE display cardiac hypertrophy with no increase in betaARK1 expression. However, Tg alpha43 animals show a reduced tolerance to 14-day PE treatment, demonstrated by reduced survival and severe cardiac hypertrophy. Moreover, PE treatment for three and seven days in Tg alpha43 mice resulted in an exaggerated hypertrophic response accompanied by significant cardiac biochemical abnormalities that are normally associated with HF, including fetal gene expression, reduced betaAR density and enhanced betaARK1 expression. We also found reduced myocardial stores of the sympathetic neurotransmitter neuropeptide Y. CONCLUSIONS: These data suggest that PE-treated Tg alpha43 mice have chronic activation of the cardiac sympathetic nervous system, which may be responsible for the appearance of apparent maladaptive hypertrophy with an evolution towards HF and sudden death. Thus, the cardiac phenotypes found in these mice are not the direct result of enhanced alpha1B AR signaling and suggest that betaARK1 is a key molecule in the transition of myocardial hypertrophy to HF.

Full Text

Duke Authors

Cited Authors

  • Iaccarino, G; Keys, JR; Rapacciuolo, A; Shotwell, KF; Lefkowitz, RJ; Rockman, HA; Koch, WJ

Published Date

  • August 2001

Published In

Volume / Issue

  • 38 / 2

Start / End Page

  • 534 - 540

PubMed ID

  • 11499749

Pubmed Central ID

  • 11499749

International Standard Serial Number (ISSN)

  • 0735-1097

Language

  • eng

Conference Location

  • United States