Chapter 5 - Catecholamines Flashcards
What NTs fall under Catecholamines?
Dopamine (DA), Norepinephrine (NE), Epinephrine
What are NE, DA, and EPI made from?
Tyrosine
Tyrosine is converted into ______ by _______. What is important about this step?
L-DOPA by tyrosine hydroxylase. It is a rate limiting step.
What is the process from tyrosine to EPI?
Tyrosine > L-DOPA > Dopamine > NE > EPI
In the process from tyrosine to EPI what are the enzymes involved?
tyrosine hydroxlase > Aromatic amino acid decarboxlase > Dopamine B-hydroxylase.
Think of it as TH > A > B
In animal models, what stereotyped behaviours are present with higher DA?
IRL
- Intense sniffing
- Repetitive head and limb movements,
- Licking and biting
DA gets packaged into what specific transporter?
A monoamine specific transporter. more specifically a VMAT (Vesicular Monoamine Transporter)
The VMAT is? What drug blocks this?
Vesicular Monoamine Transporter.
Reserpine
Why is it important to package DA in vesicles?
Otherwise it will be broken down quickly in cytoplasm
How do vesicles get released?
By exocytosis with Action Potentials
Which drugs release without cell firing?
(Meth)amphetamines.
Synaptic release occurs by _______ located on:
a. )___________
b. )___________
c. )___________
Autoreceptors located on
- cell bodies
- terminals
- dendrites
DA is produced in which 2 areas?
Mesostriatal/Nigrostriatal
and
Mesolimbocortical
DA in Mesostriatal/Nigrostriatal helps with what?
Facilitating voluntary body movements.
A loss in DA in mesocortical/nigrostriatal is associated with what?
Parkinsons Disease
DA from mesolimbocortical is associated with what?
Reward pathways and Schizophrenia
Where is NE made from?
DA (inside vesicles)
NE is made by which 3 brain areas?
a. ) locus coeruleus
b. ) lateral tegmentum area (LTA)
c. ) Dorsal medullary group (DMG)
What does NE help in modulating?
SMS
a. ) sleep/wake
b) mood
c. ) sexual behaviour
How many DA receptors are there?
Are they metabotropic or ionotropic?
5
All metabotropic
What are the sub-divisions of the receptors?
D1 like (D1 and D5) stimulatory D2 like (D2, D3 and D4) inhibitory
In animal models, what happens when you double knockout (KO) D1 and D2?
Fatality in the 2nd/3rd week of life :(
What happens when you KO DAT?
DAT hyperactivity.
Extreme hyperactivity, no response to psychostimulants
What happens when you KO D1?
D1 Deficits in KOgnitive tasks.
Deficits in several cognitive tasks
What happens when you KO D2?
impairments in: SPC
spontaneous movement
posture control
coordination
How are Catecholamines broken down? 4 ways
Reuptake
Breakdown
Transporter blocking drugs
Drugs that inhibit breakdown-enzymes
