5. Neurotransmitter Systems Flashcards
Monoamine serotonin is derived from tryptophan and is located where, has what functions?
located at raphe nuclei
functions in mood and wakefulness
Acetylcholine Location: Function: Ionotropic Receptors: Muscarinic Receptors: Other
Location: Pons/midbrain
Function: Wakefulness/motor control (REM sleep)
Ionotropic Receptors: Nicotinic
Muscarinic Receptors: Muscarinic (M1-M5)
Other: Changing subunits changes properties of channel
Acetylcholine is synthesized via choline and acetate and moved into clear vesicles via ?
vesicular Ach transporter protein (VAChT)
How is acetylcholine removed from the synapse?
acetylcholinesterase bound to post synaptic cell membrane
What are the two major inhibitory amino acids?
GABA (gamma-amino-butyric acid)
glycine
GABA Location: Function: Ionotropic Receptors: Muscarinic Receptors: Other
Location: Higher CNS (cortex/cerebellum) Function: motor control / consciousness Ionotropic Receptors: GABAa Muscarinic Receptors: GABAb Other: extrasynaptic receptors - anesthetics
GABA is synthesize from glutamate via glutamate decarboxylase (GAD). How is GABA transported into vesicles and removed from synapse?
Transported via Vesicular GABA transporter protein (VGAT)
Removed via GAT1 and GAT2
If GAT1 (which is on the presynaptic terminal) takes up GABA, then what happens?
GABA is repackaged into vesicles as is
If GAT2 (which is on the astrocyte) takes up GABA at the synpatic cleft, GABA is converted to glutamine and then what?
released to ECF where it is taken into the presynaptic terminal and made back into glutamate to make GABA
(***KNOWN as glutamate shunt)
What would happen regarding GABA if the astrocytes were not working?
an excess of glutamate is toxic and could kill the neuron
What is the difference between IPSP and EPSP?
inhibitory post-synaptic potential
excitatiry postsynaptic potential
GABAa receptor is ionotropic and produces an IPSP. What are some of the binding sites? 3
Benzodiazepine
ehtanol
some steriods
What receptors have many extra synaptic receptors which are believed to be the site of action for general anesthetics such as propofol?
GABA a receptors
GABAb receptors are metabotropic and have Gi and Go. Located presynaptically to regulate NT release and postsynaptically to inhibit cell. What does Gi and Go do?
activate K+ channel GIRK close down (inhibit) Ca+ channel
Glycine Location: Function: Ionotropic Receptors: Muscarinic Receptors: Other
Location: Spinal Cord and Lower CNS (medulla) Function: Spinal inhibitions Ionotropic Receptors: GlyR Muscarinic Receptors: None Other
How is glycine removed from the synapse?
GAT proteins - same as GABA
Purines such as ATP/ADP/adenosine, ATP is made by mT and stored in vesicles via what?
VNUT protein
ATP to ADP to Adenosine in synaptic cleft
Purines Location: Function: Ionotropic Receptors: Muscarinic Receptors: Other
Location: Cortex/Cerebellum/Hippo/Basal Ganglia
Function: Adeosine: sleep/inhibition ATP: multiple
Ionotropic Receptors: P2X
Muscarinic Receptors: P1A P2Y
Other: has cotransmitter modulator
P1A receptors only use adenosine. At post-synaptic locations it does sleep induction and inhibition, at presynpatic it does?
inhibition of NT release
P2X use ATP and P2Y (Gs/Gq) use ATP/ADP/UDP/UTP for ligand. Whatre the main functions?
learning / memory
Peptides transmitters: NT are peptides made in the soma and transported down the axon via fast axonal transport. Including what?
opiods
What can be classified as endorphins, enkephalins, dynorphins, or nociceptin?
opiods
Opiods Location: Function: Ionotropic Receptors: Muscarinic Receptors: Other
Location: Basal Ganglia, Hypothalamus, pons/medulla Function: Analgesia , mood/affect Ionotropic Receptors: None Muscarinic Receptors: Mu, Delta, Kappa Other: Peptide transmitters
What are the four precursor molecules to opiods?
proopiomelanocortinin
Proenkephalin
Prodynorphin
Orphanin FQ
Opiods are made via protein synthesis in the cell body and are removed from the synpatic cleft via reuptake and enzymatic destruction via?
enkephalinase
aminopeptidase
Opiods use u-receptors (Mu) whose activation causes what 5 things?
analgesia respiratory depression euphoria constipation sedation
Opiods also use kappa (K) receptors to produce what 2 things?
analgesia and dysphoria (unpleasant feeling)
Opiods also bind delta receptors with the main affect of?
analgesia
All opiod receptors are metabotropic (serpentine) and activate secondary messenger systems Gi and Go. What are the molecular affects of Mu Delta and Kappa?
Mu: increase in potassium efflux and hyperpolarization
Delta/Kappa: decrease calcium influx
What are endogenous canabinoids? (2)
anandamide (bliss) 2-arachidonylglycerol (2AG)
Endocannabinoids Location: Function: Ionotropic Receptors: Muscarinic Receptors: Other
Location: Basal ganglia, Spinal Cord, Cortex
Function: mood/motor performance, nociception, neuroprotection
Ionotropic Receptors: None
Muscarinic Receptors: CB-1
Other: CB-2 receptor is anti-inflammatory
Endocannabinoids are derived from membrane lipids (arachidonic acid) and occurs where?
presynaptic terminal
CB1 receptor is found on pre-synpatic terminals of EAA and GABA and reduces their release via?
Gi coupled protein, both forms are equally effective
CB2 receptor is on microglia, gut and immune system and acts as an antiinflammatory, which also increases what?
increases B-amyloid removal = help for alzheimers patients!
