Amine NTs Flashcards
What are the monoamines?
Dopamine and norepinepherine
Which AA is 5-hydroxytryptamine derived from?
tryptophan
What kind of amine is 5-hydroxytryptamine?
An indolamine
What AA are catecholamines derived from
tyrosine
Which AA is histamine derived from?
histidine
Where are the cell bodies of cells that synthesise amines?
brainstem
What is specific ab the amine neuron axons?
They project widely
What is the main role of amine NTS?
Modulating the action of GABA and glutamate at synapses
What do amines play a key role in?
Arousal, sleep, attention and survival
Where are amine NTs released from?
Boutons
What is the origin of noradrenaline in the brain?
Locus coeruleus
Where do axons of nerves in the locus coeruleus innervate?
forebrain, cortex, spinal cord
What does noradrenaline act at?
GPCRs
Which GPCRs does noradrenaline act at?
alpha 1, 2, and beta 1, 2
What do the noradrenaline GPCRs in the brain stem control?
Blood pressure
What do the noradrenaline GPCRs in the descending pathways in the spinal cord control?
Movement and pain
What do the noradrenaline GPCRs in the ascending pathways in the spinal cord control?
Arousal and mood
How is tyrosine taken up by neurons?
Via tyrosine transporters
What is tyrosine first converted into in nerve terminals?
L-dihydroxyphenylalanine
What enzyme catalyses the conversion of tyrosine to L-dihydroxyphenylalanine?
Tyrosine hydroxylase
What is L-dihydroxyphenylalanine converted into?
dopamine
What enzyme converts L-dihydroxyphenylalanine into dopamine?
DOPA d carboxylase
What takes up dopamine (in norepinepherine synthesis)?
Vesicular monoamine transporter
What is the final intermediate before noradrenaline is synthesised?
dopamine
What converts dopamine to noradrenaline
dopamine beta hydroxylase
Difference between dopaminergic neurons and noradrenaline neurons?
Noradrenaline neurons have dopamine beta hydroxylase
Eventual consequence of blocking tyrosine hydroxylase?
depleting noradrenaline
Phenotypic consequence of blocking tyrosine hyroxylase?
depression like state induced
How is noradrenaline inactivated?
Reuptake and degradation
Which compounds degrade noradrenaline?
monoamine oxidase and catechol-o-methyltransferase
Where are noradrenaline transporters expressed?
Presynaptic neurons and glial cells
What is the phenotypic result of monoamine oxidase inhibitors?
Antidepressant
Where is the origin of dopamine?
midbrain
Three dopamine pathways?
Nigro-striatal pathway, mesolimbic, tubero-infidibular system
Where does the mesolimbic pathway project from and to?
From the ventral tegmental area to the cortex and hippocampus
Where is the tubero-infundibular system located?
Hypothalamus to the pituitary gland
What type of receptors does dopamine act at?
GPCRs
What is the tubero-infundibular system involved in?
Endocrine function
What is the same between dopamine and noradrenaline?
Their inactivation (reuptake and degradation)
Which pathway degenerates in parkinsons?
Nigro-striatal pathway
Which NT does NMDA increase?
5HT
Where does 5HT arise from?
Raphe nuclei
Where does 5HT project?
Forebrain (cerebral cortex, cerebellum), spinal cord
what are the 5HT neurons in the spinal cord involved in?
pain perception and pain regulation
5HT dysfuncion is associated with?
depression, sleepy, abnormal feeding
Increased activity of 5HT systems in regard to food?
Loss of appetite
Decreased activity of 5HT systems in regard to food?
Gain of weight
How is tryptophan taken up by NTs?
transporters
First thing to happen to tryptophan in 5ht synthesis?
Conversion to 5-hydroxytryptophan
Which enzyme catalyses the conversion of tryptophan to 5-hydroxytryptophan?
Tryptophan hydroxylase
What is 5-hydroxytryptophan converted to?
5-hydroxytryptamine
What enzyme catalyses the formation of 5-hydroxytryptamine
5-hydroxytryptophan carboxylase
What happens to 5-hydroxytryptamine after synthesis?
taken up by vesicles
Inactivation of 5ht?
Reuptake and degradation
5ht degredation enzyme?
Monoamine oxidase
What is unique ab 5HTs reuptake transporters?
They are specific to 5HT
Where does ACh project to from the magnocellular neurons?
cortex/limbic system
Types of ACh receptor?
Ionotropic and GPCR
Ionotropic ACh receptor?
Nicotinic
GPCR ACh receptor?
Muscarinic
Role of ACh?
Arousal, sleep, waking
Main substrate for ACh?
Choline
How is ACh formed?
Choline combines with acetyl-CoA
enzyme catalysing ACh formation?
Choline acetyltransferae
Which enzyme breakd down ACh?
Acetylcholineesterase
WHat is produced as a result of ACh breakdown?
Free choline, acetic acid
what is taken up after ACh degredation?
Free choline
Treatment for alzheimers regarding ACh?
Targets acetylcholineesterase to prevent ACh degradation