Increased myocardial contractility and enhanced exercise function in transgenic mice overexpressing either adenylyl cyclase 5 or 8.

Journal Article

OBJECTIVE: ss-adrenergic receptors (ssARs) are powerful regulators of cardiac function in vivo, activating heterotrimeric G proteins and the effector molecule adenylyl cyclase (AC). Interestingly, cardiac-specific overexpression of different AC isoforms leads to variable changes in cardiac function. Whether AC overexpression affects intrinsic cardiac contractility in an isoform-specific fashion determining a change in exercise capacity is currently unknown. METHODS: To address this issue, we performed load-independent measurements of cardiac systolic and diastolic function by pressure-volume (PV) loop analysis in intact wild-type mice (WT) and transgenic mice overexpressing the AC isoforms 5 or 8. RESULTS: Here we show that cardiac overexpression of either AC5 or AC8 transgenic mice determined an increase in intrinsic cardiac contractility. Interestingly, AC8 transgenic mice displayed a significantly greater increase in cardiac contractility and improved active phase of relaxation. Despite these differences detected by PV loop analysis, both AC5 and AC8 mice showed a marked increase in exercise capacity on treadmill testing. CONCLUSIONS: Our results demonstrate that load-independent measurements of cardiac function are needed to compare different groups of genetically-modified mouse models and to detect subtle AC isoform-specific changes in cardiac performance.

Full Text

Duke Authors

Cited Authors

  • Esposito, G; Perrino, C; Ozaki, T; Takaoka, H; Defer, N; Petretta, MP; De Angelis, MC; Mao, L; Hanoune, J; Rockman, HA; Chiariello, M

Published Date

  • January 2008

Published In

Volume / Issue

  • 103 / 1

Start / End Page

  • 22 - 30

PubMed ID

  • 18034275

International Standard Serial Number (ISSN)

  • 0300-8428

Digital Object Identifier (DOI)

  • 10.1007/s00395-007-0688-6

Language

  • eng

Conference Location

  • Germany