Exam1Lec4Synthesis,Storage,andReleaseofNeuro Flashcards
What are gap junctions?
physical/direct connections that allow electrical coupling b/w 2 neurons
all cells have this except skeletal muscles dont have this
What are chemical synapses?
where neurotransmitters are released by the pre-synaptic cell via exocytosis
What determines whether or not a substance is a neurotransmitter?
4 criteria
1. Synthesized and/or stored in the pre-synaptic cell
2. Targets sites on a post-synaptic receptor
3. Endogenous + exogenous transmitter =same response
4. Has a mechanism to terminate, or deactivate the signal
What are the diff types of neurotransmitters?
small molecules, amino acids, peptides, gases,purines, biogenic amines
What is exocytosis caused by?
caused by an increase in cytosolic Ca2+ resulting from the depolarization-dependent activation of Ca2+ channels.
What is receptor activation?
Neurotransmitter binds (2 mechanism) to postsynaptic receptor, and alters (diverse response) the postsynaptic Vm
What is receptor inactivation (removal)?
Transmitters are removed from the synaptic cleft primarily through three mechanisms
What is the order of synpatic transmission?
transmitting the ap to another cell
slide 6
NT packaged in vesicle > Docking > Priming > Exocytosis > Endocytosis
exocytosis of neurotran from vesicle into synaptic cleft
endocygtisis: membrane from pre-synaptic terminal to recycle more vesivles for neurotrans
Explain electrical synapse vs chemical synpase
electrical synapse: Passive communication via the direct electrical coupling of two cells through gap junctions.
chemical synapse:Communication through the release
and binding of molecules known as
neurotransmitters.
What are pore forming proteins (connexins) connecting two cells?
Gap junctions (part of electrical synpase)
many indiv connexins make one connexon thats in one side of membrane andanother on the other side. They come together and makes a hemichannel which makes gap junctions.
What are the limitations and advantages of electrical synapses?
Advantage: Rapid signal transmission
(electrical and chemical)
Limitation: Postsynaptic = Presynaptic (Identical signal, ie. less plasticity)
Examples: Coupling among retinal cells, cancer cells or heart muscle
What are the limitations and advantages of chemical synapses?
Limitation: slower signal transmission
Advantage: postsynpatic signal varies from presynaptic signal
as ca2+ incr, neurotrans incr
What are the 6 main types of small molecule neurotransmitters?
1) Acetylcholine
2) Amino Acids
3) Purines
4) Biogenic Amines
5) Gases (NO, CO)
6) Peptides (much larger)
- BDNF and NGF are “neurotransmitter modulators”
Amino acid transmitters can be divided into what
Inhibitory: GABA and glycine. (IPSPs, influx of Cl- ions and/or efflux of K+ ions ) DECR LIKELIHOOD OF AP
excitatory: glutamate and to a lesser extent aspartate. (associated primarily with EPSPs) INCR LIKELIHOOD OF AP
GABAergic Drug examples (activates gaba): Phenobarbital, Diazepam, Vigabatrin
Excitatory Drug examples: Antagonists are Ketamine, Riluzole, and MSG is an Agonist
What is the most abundant neurotransmitter in the body?
Glutamate (very ubiquitos)
What are 5 examples of peptide neurotransmitters?
- Brain-gut peptides
- Opiod peptides
- Pituatary peptides
- Hypothalamic-releasing peptides
- Miscellaneous peptides
need to be injected bc digestive tract will cleave them, making them inactive
What is the life cycle of a neurotransmitter?
life cycle of neurotransmitters: 1) synthesis, 2) packaging, 3) release, 4) binding, and 5) inactivation
Explain the synthesis of catecholamines
We need Tyrosine (from diet or phenylalanine) to turn into L-DOPA, then to turn into Dopamine, then into Norepi, then to Epi
Enzyme to turn L-dopa to dopamine is DOPA decarboxylase