Epinephrine & Norepinephrine (Catecholamine)

• Epinephrine hormone produced by adrenal medulla (above kidneys) and is also a NT in the brain

• Norepinephrine (NE) is synthesized from dopamine within vesicles

  • Almost every brain region gets input from noradrenergic neurons
  • Generally the behavioral effect of NE is excitatory

• NE helps with alertness & arousal (vigilance)

  • Detect important stimuli; also sexual behavior & appetite control

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NE found in neurons in the Autonomic Nervous System (part of the PNS)

Adrenalin=epinephrine as noradrenalin=norepinephrine (referred to as noradrenergic)

The locus coeruleus (located in dorsal pons) gives rise to NE fiber systems

NE not often released from terminal buttons: NE released through axonal varicosities (swellings on the axonal branches).

Adrenergic (NE & EPI) receptors can be inhibitory and excitatory but primarily what we can observe is excitatory response to NE release.

The drug AMPT prevents L-DOPA production and thus blocks production of dopamine and norepinephrine

Fusaric acid blocks only the production of norepinephrine