 Once in the synapse , norepinephrine binds to and activates receptors . After an action potential , the norepinephrine molecules quickly become unbound from their receptors . They are then absorbed back into the presynaptic cell , via reuptake mediated primarily by the norepinephrine transporter ( NET ) . Once back in the cytosol , norepinephrine can either be broken down by monoamine oxidase or repackaged into vesicles by VMAT , making it available for future release . 
