The Biogenic Amines Flashcards
Name the 5 Biogenic amine neurotransmitters
3 Catecholamines: Dopamine, Norepinephrine, and Epinephrine
Histamine
Serotonin
Catecholamines are derived from this common precursor:
The amino acid Tyrosine
The first step in synthesizing a catecholamine is to:
Synthesize dihydroxyphenylalanine (DOPA)
What is required to synthesize DOPA?
Needs a reaction of Tyrosine hydroxylase, Oxygen (substrate), and tetrahydrobiopterin (co-substrate)
Dopamine is produced by what action?
The action of DOPA decarboxylase on DOPA
Major Dopamine containing area of the brain
Corpus Striatum
What is the Corpus Striatum?
a collective name given to the caudate nucleus and lentiform nucleus within the basal ganglia.
The Corpus Striatum receives input from
All over the cortex and importantly the substantia nigra at the base of the midbrain
Corpus Striatum play an essential role in what?
coordination of body movements.
What’s up with Parkinson’s and Dopamine?
Dopaminergic neurons of the substantia nigra degenerate leading to motor dysfunction
Besides motor movements what else does Dopamine play a role in?
motivation, reward, and reinforcement.
What’s up with Cocaine and Dopamine?
Cocaine acts by stimulating the release of Dopamine
Dopamine binds to…
Dopamine receptors and certain β-adrenergic receptors
What’s up with Dopamine and the treatment of Shock?
It’s used clinically to treat shock because it dilates renal arteries through dopamine receptor activation and increases cardiac output by activating β-adrenergic receptors in the heart
The synthesis of Norepinephrine requires
dopamine β-hydroxylase and the transport of dopamine into adrenergic terminals via vesicles
The most prominent class of neurons that synthesize norepinephrine is
sympathetic ganglion cells
Norepinephrine is also highly utilized by this brain region
Locus Coerulus
Norepinephrine in the Locus Coerulus influences:
sleep & wakefulness
Attention
Feeding Behavior
Among the Catecholamines, this one is present at lower levels
epinephrine
Enzyme that synthesizes epinephrine
phenylethanolamine-N-methyltransferase
Phenylethanolamine-N-methyltransferase is found only in
epinephrine-secreting neurons
Epinephrine containing neurons in the CNS are found in two groups in this brain region:
rostral medulla
What is the function of epinephrine in the rostral medulla
This is not known
What happens after to catecholamines left in the synaptic gap?
They are removed by reuptake into nerve terminals or surrounding glial cells by a Na+ dependent transporter.
Two major enzymes involved in catabolism of catecholamines are:
Monoamine Oxidase (MAO) and Catechol O-methyltransferase (COMT)
Histamine is produced from this amino acid
Histidine
Histamine is metabolized by
Histamine methyltransferase AND MAO combined actions
High concentrations of histamine are found in
the hypothalamus
What does the central histamine projections mediate?
arousal and attention
When is Histamine released from Mast cells?
In response to allergic reactions or tissue damage
Chemical name of Serotonin
5-hydroxytryptamine (5-HT)
5-HT is synthesized from this amino acid
tryptophan
How is tryptophan hydroxylated? By what enzyme?
Tryptophan is taken into the neuron by a plasma membrane transporter.
The enzyme that catalyzes the reaction is tryptophan 5-hydroxylase
Where is Serotonin located?
in neurons of the raphe region of the pons and upper brainstem (with wide projections into the forebrain)
What has Serotonin been implicated in the regulation of?
Sleep and wakefullness
