Biosynthesis and Signaling of Acetylcholine and Adrenaline

Acetylcholine

Neurotransmitter synthesized from choline and acetylCoA.

Choline Acetyltransferase

Enzyme that synthesizes acetylcholine in neurons.

how is acetylcholine synthesised

• choline and acetylCoA

• choline acetyltransferase

Cholinergic Signaling

Fast synaptic transmission using acetylcholine.

Acetylcholinesterase

Enzyme that degrades acetylcholine in synapses.

key features of acetylcholine

• permanently positively charged nitrogen

  • key for binding to receptors

• ester group

  • links choline to the acetyl group

Ester Group in acetylcholine

Chemical group linking choline to acetyl in acetylcholine.

structure of acetylcholine

Permanently Positively Charged Nitrogen

Key feature of acetylcholine for receptor binding.

Biosynthesis of Adrenaline

Process converting tyrosine to adrenaline through intermediates.

Tyrosine Hydroxylase

Enzyme converting tyrosine to L-DOPA.

DOPA Decarboxylase

Enzyme converting L-DOPA to dopamine.

Dopamine Beta-Hydroxylase

Enzyme converting dopamine to noradrenaline.

Phenyl Ethanolamine N-Methyltransferase

Enzyme converting noradrenaline to adrenaline.

VMAT

Vesicular transporter packaging and releasing monoamines.

Adrenoreceptors

G protein-coupled receptors for adrenergic signaling.

Alpha1 Adrenoreceptor

Coupled with Gq, relevant to cardiovascular disorders.

Alpha2 Adrenoreceptor

Linked to Gi, involved in inhibitory signaling.

Beta1 Adrenoreceptor

Linked to Gs, stimulates cardiac function.

NET

Transporter for noradrenaline reuptake into neurons.

Monoamine Oxidase

Enzyme metabolizing noradrenaline in surrounding cells.

Catechol-O-Methyltransferase (COMT)

Enzyme metabolizing catecholamines like noradrenaline.

Fast Synaptic Transmission

Rapid communication between neurons via neurotransmitters.

adrenergic transmission

• tyrosine enters by the aromatic amino acid transporter AAAT

• packaged into vesicles by transporter cells called vesicular monoamine transporter (VMAT)

• VMAT then releases adrenaline and binds to adrenoreceptor

adrenoreceptors vs nicotinic acetylcholine receptors

slower