A new study published in Science Advances shows female and male hearts respond differently to the stress hormone noradrenaline. The study in mice may have implications for human heart disorders like arrhythmias and heart failure and how different sexes respond to medications.
The team built a new type of fluorescence imaging system that allows them to use light to see how a mouse heart responds to hormones and neurotransmitters in real time. The mice were exposed to noradrenaline, also known as norepinephrine. Noradrenaline is both a neurotransmitter and hormone associated with the body’s “fight or flight” response.
The results reveal that male and female mouse hearts respond uniformly at first after exposure to noradrenaline. However, some areas of the female heart return to normal more quickly than the male heart, which produces differences in the heart’s electrical activity.
“The differences in electrical activity that we observed are called repolarization in the female hearts. Repolarization refers to how the heart resets between each heartbeat and is closely linked to some types of arrhythmias,” said Jessica L. Caldwell, first author of the study. Caldwell is a postdoctoral scholar in the UC Davis School of Medicine Department of Pharmacology.