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