5.1 Neurotransmitter Systems (Karius) Flashcards
What are the functions of the dopamine receptors we know of?
D1 and D2 funcitons in the substantia nigra.
D3 is involved in the pleasure and reward system.
Where is norepinephrine located in the CNS?
Locus ceruleus
(spelling varies)
What is the function of the tuberinfundibular pathway?
This is the pathway in which dopamine can supress prolactin.
Runs from the hypothalamus to the anterior pituitary.
What symptom is a consequence of NO synthesis in the pons?
Apneusis
What enzyme converts norepinephrine into epinephrine?
PNMT
(Phenylethanolamine-N-methyl transferase)
What is the function of the mesocortical dopaminergic pathway?
Crucial to attention and higher consciousness.
Dysfunction leading to schizophrenia.
What are the two endocannabinoids?
Anandamide
2AG (2-arachidonylglycerol)
Where is serotonin located in the CNS?
In the midline raphe nuclei.
What is directly caused by activation of the NMDA channel?
What molecules are required for NMDA channel activation?
Opening of a calcium channel.
Glutamate or aspartate and glycine.
What are the receptors for dopamine?
What G proteins are they coupled to?
D1 through D5
D1 and D5 are coupled to Gs
D2, D3, and D4, are coupled to Gi
What is the function of serotonin in the CNS?
Serotonin in the midline raphe nuclei functions in attention and mood - as well as pain transmission in the spinal cord.
Disruptions are associated with depresion.
What are the two enzymes that reclaim GABA, and where are they located?
GAT1 is found on the presynaptic terminal for direct recycling.
GAT2 is found on glial cells, where GABA is converted backwards into glutamine, and is then sent to the presynaptic neuron.
What enzyme clears histamine from the synapse?
Diamine oxidase
How might anesthetics cause unconsciousness?
They have binding sites on the GABAA receptor, causing an influx of Cl-.
They also have binding sites on glycine receptors, allowing an influx of chloride as well.
What transporter class moves dopamine into vesicles?
Which specific transporter is found in the neurons?
VMATs move dopamine into vesicles.
VMAT 2 is found in monoamine releasing neurons. (Whereas VMAT 1 is found in the adrenal medulla)
What are the three opiod receptors?
μ-receptor
κ-receptor
δ-receptor
What are the two types of non-NMDA receptors, and what are the characteristics of each?
- AMPA receptors
- Glutamate and aspartate are the endogenous ligands
- There is a binding site for benzodiazepines on the AMPA receptor (as well as on the GABA receptor) which blocks them, decreasing sodium influx. This causes the sedative effect.
- Kainate receptors
- Simply binds to glutamate or aspartate and lets sodium in. No other cool facts here – except that it’s exogenous ligand “kainate” was originally derived from seaweed, and is called “Kainin-sou” in japan. #Darrenfacts
What enzyme clears serotonin from the synapse?
MAO, just like the catecholamines.
What GABA receptor is ionotropic, and what ion is admitted?
GABAA is ionotropic, and lets in chloride.
What two enzymes remove dopamine, epinephrine, and norepinephrine from the synaptic terminal?
MAO (monoamine oxidase)
COMT (Catechol-O-methyl Transferase)
(Mostly MAO in the CNS, whereas COMT is more common in the PNS)
What is the P1 purine receptor specific for?
Is it ionotropic or metabotropic?
What are its functions?
P1 is specific for adenosine.
Presynaptic P1 receptors inhibit NT release. Postsynaptic receptors inhibit neural function, and are specifically associated with sleep induction.
(Caffeine blocks P1 adenosine receptors)
How are excitatory amino acids removed from the synapse?
Glial cells take them up and convert them back down to a less toxic molecule (eg: glutamate to glutamine).
What amino acid is synthesized into histamine?
Histidine
What three receptor types are there for norepinephrine and epinephrine?
What G proteins are they coupled to?
Alpha 1 = Gq
Alpha 2 = Gi
Beta = Gs