Adrenergic receptor; simplified schematic view of adrenergic nerve ending and the effector cell with its receptors. When norepinephrine is released, it enters the synaptic cleft to bind to α1- and β-adrenergic receptors on the effector cell; there is also a short feedback loop in which norepinephrine binds to α2- and β-adrenergic receptors on the neuron to inhibit or stimulate further release, respectively.
Medical dictionary. 2011.