5.3 Flashcards
(31 cards)
What are the four steps of chemical synaptic transmission?
1) Neurotransmitter synthesis/storage, 2) Release, 3) Receptor/ion channel/transport interaction, 4) Removal.
What are the major excitatory and inhibitory neurotransmitters?
Glutamate (excitatory), GABA (inhibitory).
What do excitatory neurotransmitters do?
Cause membrane depolarisation.
What do inhibitory neurotransmitters do?
Cause membrane hyperpolarisation.
Why is neurotransmitter removal important?
To terminate the signal and prevent receptor desensitisation.
What drives secondary active transport?
The concentration gradient of ions, typically sodium (Na⁺).
What types of neurotransmitters use secondary active transport?
Serotonin (5-HT), noradrenaline, dopamine, GABA, glutamate, glycine.
What are the two classes of neurotransmitter transporters?
NSS family and Dicarboxylate/amino acid cation symporters.
What does SERT transport?
Serotonin (5-HT), Na⁺, and Cl⁻ into the cell; K⁺ out.
What kind of transport does SERT perform?
Both symport and antiport (secondary active).
What drug class targets SERT?
Selective serotonin reuptake inhibitors (SSRIs).
Fluoxetine
How does fluoxetine (Prozac) act?
Blocks SERT to increase extracellular serotonin levels.
What is serotonin syndrome?
A rare, potentially lethal condition caused by excessive 5-HT accumulation in the CNS.
What is the function of EAATs?
Remove glutamate from the synapse.
How do EAATs operate?
Co-transport 3 Na⁺, 1 H⁺, and counter-transport 1 K⁺ per glutamate.
Why are EAATs important in disease?
Dysfunction linked to neurological disorders like ALS; used to study glutamate excitotoxicity.
Where is glycine an important neurotransmitter?
Inhibitory signalling in the spinal cord and brain.
What do glycine receptors do?
Cause Cl⁻ influx → membrane hyperpolarisation.
Where are GlyT1 and GlyT2 located?
GlyT1: glial cells; GlyT2: neurons.
How do glycine transporters operate?
Co-transport Na⁺ and Cl⁻ along with glycine.
What is reverse transport in GlyT1?
GlyT1 can release glycine under some conditions to supply NMDA receptors.
Why doesn’t GlyT2 perform reverse transport?
Intracellular glycine concentration is too high.
What drug classes can inhibit GlyT function?
Tricyclic antidepressants and antipsychotics (e.g., haloperidol, clozapine).
What therapeutic area are GlyT inhibitors being explored for?
Neuropathic pain treatment.
