Synaptic Trans SDL1 Flashcards
Where synaptic vesicles aggregate before release
presynaptic density, active site
Where receptor aggregate
postsynaptic density
electrical junctions
gap junctions, bidirectional, fast
chemical transmission
chemical synapse, unidirectional, slow, better controlled
Criteria for NT
localization, release, mimicry, inactivation
Tyrosine Derivatives?
Epinephrine, Dopamine, Norepinephrine
NT synthesis and packaging
step- by-step from readily available precursors
Enzymatic Control of Synthesis
enzyme molecule concentration, rate limiting step, phosphorylation, specificity
where are peptide neurotransmitters made?
soma –> nerve terminal
where are small molecules made?
ACh, Epi made in nerve terminal
What do autoreceptors do?
bind NT and modulate release of transmitter
AP sequence?
Depolarization –> Ca2+ influx at terminal –> exocytosis of vesicle
Binding of NT to postsynaptic receptor (3)
- single transmitter can bind multiple times
- usually reversible
- effect is concentration dependent
High concentration of NT may cause…
binding to specific and non-specific receptors –> undesirable side effects if non-specific activate
Termination of NT action (4)
- extracellular degradation enzymes
- specific reuptake proteins
- diffusion of NT away
- internalization of ligand-receptor complex
What are the two classes of postsynaptic receptors?
ionotropic and metabotropic
What is an ionotropic receptor?
ligand-gated, fast ex: ACh nicotinic
What is a metabotropic receptor?
G-protein coupled, slow ex: ACh muscarinic receptor
Characteristics of Ionotropic
fast onset, short duration, direct effect on channel, no second messenger or amplification
Characteristics of Metabotropic
slow onset, long duration, no ion channel, no direct effect on channel, second messenger and amplification
What determines excitation or inhibition?
receptor
Excitation
Depolarization, excitatory
Inhibition
Hyperpolarization, Inhibitory