Presynaptic receptors.
D005246:Feedback; D009411:Nerve Endings / Q000378:metabolism*; D009420:Nervous System / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism; D011941:Receptors, Adrenergic / Q000378:metabolism*; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D017981:Receptors, Neurotransmitter / Q000378:metabolism*
D018377:Neurotransmitter Agents; D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D017981:Receptors, Neurotransmitter; D009638:Norepinephrine