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).