Yohimbine can exacerbate heart failure by increasing blood pressure through alpha-2 adrenergic receptor antagonism. Mydriasis can be induced via modulation of adrenergic or cholinergic signalling. These compounds interact with cell surface adrenergic receptors. It also interacts with other serotonin, adrenergic and dopamine receptors. It works mainly by increasing the activity of norepinephrine (noradrenaline) on adrenergic receptors. Labetalol is highly selective for postsynaptic alpha1- adrenergic, and non-selective for beta-adrenergic receptors. Epinephrine acts by binding to a variety of adrenergic receptors. Additionally, it inhibits the release of norepinephrine from adrenergic nerves. Hand-warming involves arteriole vasodilation produced by a beta-2 adrenergic hormonal mechanism. Its actions vary by tissue type and tissue expression of adrenergic receptors. Adrenaline acts by binding to a variety of adrenergic receptors. Prominent among these is its reactivity to adrenergic stimulation. This is a list of adrenergic drugs.