Chronic isoprenaline/phenylephrine vs. exclusive isoprenaline stimulation in mice: critical contribution of alpha1-adrenoceptors to early cardiac stress responses

Mice were subjected to either isoprenaline (ISO, 30 mg/kg*d) or isoprenaline and phenylephrine (ISO/PE, 30 mg/kg*d each) for a period of 4 days via osmotic minipumps. At that timepoint, both ISO and ISO/PE treated animals showed a similar increase in heart weight to tibia length ratios. ECG-telemetry data collected from other individuals indicate a similar increase heart rate and normal blood pressure after 4 days of both ISO and ISO/PE exposure. Cardiac function was not assessed at that particular timepoint. Cardiac bulk from control, ISO and ISO/PE treated mice