Esmolol is a cardioselective beta1 receptor blocker with rapid onset, a very short duration of action, and no significant intrinsic sympathomimetic or membrane stabilising activity at therapeutic dosages.
Esmolol acts as a pharmacochaperone: Long term exposure of cells to esmolol raised the surface levels of β1-adrenergic receptors[1].
[1] Nasrollahi-Shirazi S, et al. J Pharmacol Exp Ther. 2016, 359(1):73-81.