NROSCI: unit 3: synaptic transmission

GABA is always

inhibitory

2 types of receptors NT

ionotropic metabotropic

Synaptotagmin

calcium sensor

neuropeptides act as

hormones

exocytosis takes place in

presynaptic vesicles

SNARE proteins process? how many? list them

- participate in exocytosis -4 of them: synaptobrevin, syntaxin, SNAP-25, Synaptotagmin

deactivating NT 3 ways:

1. enzymatic breakdown in synapse 2.glial cell reuptake 3. reuptake by presynaptic neuron via transporter

3 locations where metabotropic receptors are found

1. presynaptic- autoreceptors; neg feedback loop in case of too much NT release 2. postsyaptic- module IPSPs, EPSPs, potential, etc 3. extrasynaptic-modulate neural excitability

4 criteria for neurotransmitters

1. synthesized and stored in presynaptic neuron 2. released in response to AP 3. have specific receptors 4. mechanisms to deactivate from synaptic cleft

steps of exocytosis

1.docking-vesicles move closer to cell membr 2.priming-Ca 2+ reacting protein joins docking proteins 3.fusion- Ca 2+ enters neurons and triggers fusion of vesicle with membrane which leads to NT release

(SELECT ALL) You are trying to treat a disorder where there is not enough neurotransmitter "x" signaling. Which of the following strategies would you use to design your treatment drug? a. block the autoreceptor for "x" b.Block the postsynaptic ionotropic receptor for "x" c.Block the postsynaptic metabotropic receptor for "x" d.Block the enzyme that breaks down "x" in the synaptic cleft e.Block the transporters for "x"

a. block the autoreceptor for "x" d.Block the enzyme that breaks down "x" in the synaptic cleft e.Block the transporters for "x"

(SELECT ALL) Which statements describe a typical neurotransmitter? a.Synthesized and stored in the presynaptic cell b.Released in response to an action potential c.Have specific post-synaptic receptors d.Are only excitatory e.Have mechanisms for removal from synaptic cleft

a.Synthesized and stored in the presynaptic cell b.Released in response to an action potential c.Have specific post-synaptic receptors e.Have mechanisms for removal from synaptic cleft

Saltatory conduction is the process in which _______ is propagated by "jumping" from __________ to _________. a.an action potential, node of Ranvier to node of Ranvier b.a graded potential, node of Ranvier to node of Ranvier c.an action potential, myelin sheath to myelin sheath d.a graded potential, myelin sheath to myelin sheath

a.an action potential, node of Ranvier to node of Ranvier

botox prevents release of what NT

acetylcholine ACh

When an action potential invades the terminal, calcium comes into the cell and binds to ____. a.All SNARE proteins b.Synaptotagmin c.Voltage-gated calcium channels d.Neurotransmitter vesicles

b.Synaptotagmin

dynamin

breaks vesicle off cell membrane

What makes a neuron inhibitory? a.It is very difficult to get them to fire an action potential b.They only release negative neurotransmitters c.The receptors on postsynaptic cells cause IPSPs d.They depolarize the postsynaptic neuron

c.The receptors on postsynaptic cells cause IPSPs

When an action potential reaches the axon terminal, release of neurotransmitter is directly triggered by... a. movement of sodium ions into the axon terminal b.movement of potassium ions out of the axon terminal c.movement of calcium ions into the axon terminal d.movement of sodium ions into the neuron at the nodes of Ranvier e.movement of calcium ions into the neuron at the nodes of Ranvier

c.movement of calcium ions into the axon terminal

Clathrin

coats vesicle membrane from inside of cells and pulls it into neuron

Syntaxin/ SNAP-25

connected to pre-synatpic terminal membrane

Synaptobrevin (VAMP)

connected to vesicle membrane

You are studying a new drug X in the lab, and want to see what its effects are on neurons. You have neurons at rest in a dish and are recording from one with an electrode. You apply the drug and see a fast hyperpolarization of the membrane. What type of receptor is the drug most likely binding to? And what is the effect? a.Voltage gated ion channel; EPSP b.Voltage gated ion channel; IPSP c.Ionotropic receptor; EPSP d.Ionotropic receptor; IPSP e.Metabotropic receptor; EPSP f.Metabotropic receptor; IPSP

d.Ionotropic receptor; IPSP

what are the two types of synapses

electrical and chemical

define synapse

functional connection between neurons

electrical synapses describe define? speed? direction? graded or not? AP necessary or not? Used when? example?

gap junctions formed of connexons in both membranes that line up passive ion flow through gap junctions extremely fast graded flow in any direction AP not necessary ONLY used in 3 scenarios: 1.fast transmission of current 2. synchronize neural netowrks 3. communication between glia ex) cray fish escape response

ionotropic receptor characteristics

ligand gated, direct, fast

Chemical synapses define? slow or fast compared to electrical? direction?

presynaptic release and postsynaptic binding of NT delayed transmission unidirectional

Endocytosis is basically like ---, explain the process, and name the two proteins involved

recycling, vesicle membrane is brought back into presynaptic terminal -budding. this can be packaged wiht more NT/reused or it can be broken down 2 proteins: clathrin dynamin

metabotropic receptor characteristics

slower, longer lasting, G-protein couples

2 categories of NT

small molecule NT large molecule NT (neuropeptides)

small molecule NT are made at --- while neuropeptides are made at --- small molecule NT mediate ---synaptic actions while neuropeptides mediate --- synaptic actions

terminal soma fast, slow

toxins that affect SNARE proteins

tetanus and botulism

what determines whether a NT is inhibitory or excitatory

the receptor they bind to