Amine Neurotransmitters Flashcards
What are the main amine neurotransmitters in the CNS?
Noradrenaline (NA), Dopamine (DA), Serotonin (5HT), Acetylcholine (ACh), and Histamine
What are the two categories of amine neurotransmitters?
Catecholamines (e.g., dopamine, noradrenaline) and Indoleamines (e.g., serotonin).
Where do noradrenaline pathways in the CNS originate?
The locus coeruleus in the brainstem
What are the main functions of noradrenaline in the CNS?
Arousal, mood regulation, attention, learning, memory, movement, and blood pressure control
What enzymes degrade noradrenaline?
Monoamine oxidase (MAO) and Catechol-O-methyltransferase (COMT).
What neurotransmitter is known as the “reward chemical”?
Dopamine (DA)
Name the main dopamine pathways in the CNS
Nigrostriatal, Mesocorticolimbic and tuberoinfundibular pathways.
What disorders are associated with dopamine dysfunction?
Parkinson’s disease, schizophrenia, and addiction.
What enzymes degrade dopamine?
MOA and COMT
What are the functions of serotonin (5HT) in the CNS?
Regulation of mood, sleep, appetite, and sensory transmission.
What is the precursor to serotonin (5HT)?
Tryptophan
Which enzyme is the rate-limiting step in serotonin synthesis?
Tryptophan hydroxylase
What are the two main types of acetylcholine receptors?
Nicotinic (ionotropic) and muscarinic (GPCR)
What are the key functions of acetylcholine in the CNS?
Arousal, learning, memory, and motor control.
What enzyme inactivates acetylcholine?
Acetylcholinesterase (AChE)
Where is histamine synthesised in the brain?
The tuberomammillary nucleus of the hypothalamus.
What are the key roles of histamine in the CNS?
Arousal, attention, learning, memory, and regulation of feeding and energy balance.
What are the two forms of COMT and where are they found?
Membrane-bound COMT (MB-COMT) in the brain and soluble COMT (S-COMT) in peripheral tissues.
How do MAO inhibitors work as antidepressants?
They block the degradation of monoamine neurotransmitters, increasing their levels in the brain.
What is the clinical significance of the mesocorticolimbic dopamine pathway?
It is involved in reward, emotion, and schizophrenia.
What class of drugs is used to treat Parkinson’s Disease by inhibiting dopamine degradation?
MAO-B inhibitors and COMT inhibitors.
How do SSRIs treat depression?
They block serotonin reuptake, increasing its availability at synapses.
What neurotransmitters is linked to Alzheimer’s disease due to its role in learning and memory?
Acetylcholine (ACh)
What type of histamine receptor antagonist is used as a sedative?
H1 antagonists that cross the blood-brain barrier (e.g. diphenhydramine).
