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Adrenergic Transmission

Adrenergic Transmission

• Neurotransmitter: Noradrenaline (Norepinephrine)

• Sites

  • Sympathetic postganglionic neuron.

    • Except: Sweat glands, some vasodilator fibers

  • Brain

Steps

Tyrosine

↓ Tyrosine hydroxylase

DOPA

↓DOPA decarboxylase

Dopamine

↓

Transported into the vesicle by Vesicular Monoamine Transporter (VMAT)

↓

Dopamine

↓β hydroxylase

Noradrenaline

↓

Complexed with ATP ⟶ adsorbed on chromogranin

↓

Nerve impulse coupled release

↓

Acts on adrenergic receptors on postsynaptic membrane

↓

1. 75-90% is taken back in nerve terminal by Norepinephrine transporter(NET) ⟶ most of it is transported into the vesicle by VMAT; some is degraded by Monoamine Oxidase (MAO).

2. Some noradrenaline diffuses away ⟶ Degraded by Catechol O Methytransfarase (COMT).

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▶️ Adrenergic Receptors