Cardiac stimulation via sympathetic neurons can potentially trigger arrhythmias.
We have co-cultured stellate ganglion sympathetic neurons with cardiac myocytes and have used optical methods to study their interactions and electrophysiology.
In this study, we demonstrate the utility of optical interrogation of sympathetic neurons and their effects on macroscopic cardiomyocyte network dynamics to address research targets such as the effects of adrenergic stimulation via the release of neurotransmitters, the effect of neuronal numbers on cardiac behaviour, and the applicability of optogenetics in mechanistic in vitro studies. As arrhythmias are emergent behaviours that involve the coordinated activity of millions of cells, we image at macroscopic scales in order to capture complex dynamics.
In healthy tissue, the presence of neurons acts to stabilise the excitation patterns within the heart. However, when tissue has become damaged, it becomes much more excitable, and neural activity can establish an aberrant wave that could lead to a sustained heart arrhythmia. Our cell culture results imply that the sensitivity of cardiac tissue to neural activity is much higher than previously thought, as very few neurons are needed to disrupt normal propagation. This method provides an optimal high-throughput approach to screen for new drugs that will limit the influence of these border zones on normal heart rhythm.
Link to the paper: https://www.sciencedirect.com/science/article/pii/S2589004220305216