Short communicationGuanfacine enhances cardiac acetylcholine release with little effect on norepinephrine release in anesthetized rabbits

•Microdialysis technique was applied to the rabbit's atrial myocardium.•Guanfacine significantly increased cardiac vagal acetylcholine release.•Guanfacine hardly affected cardiac sympathetic norepinephrine release.

An α2A-adrenergic agonist guanfacine improves autonomic imbalance in attention-deficit hyperactivity disorder, suggesting that it may be useful to correct autonomic imbalance in chronic heart failure (CHF) patients. To investigate the effects of guanfacine on cardiac autonomic nerve activities, a microdialysis technique was applied to anesthetized rabbit heart. Acetylcholine (ACh) and norepinephrine (NE) concentrations in atrial dialysates were measured as indices of cardiac autonomic nerve activities. Guanfacine at a dose of 100 μg/kg significantly decreased heart rate and increased dialysate ACh concentration without decreasing sympathetic NE release. Guanfacine may be useful for vagal activation therapy in CHF patients.

Graphical abstractDownload high-res image (66KB)Download full-size image