Term
| What drug that blocks the gating action of acetylcholine on the acetylcholine channels by competing for the acetylcholine receptor sites? |
|
Definition
|
|
Term
| What inactivate the acetylcholinesterase in the synapses so that it no longer hydrolyzes acetylcholine? |
|
Definition
| neostigmine, physostigmine, and diisopropyl fluorophosphate |
|
|
Term
| What group of drugs can prevent passage of impulses from the nerve ending into the muscle? |
|
Definition
|
|
Term
| What compounds have the same effect on a muscle fiber as ACh? |
|
Definition
| methacholine, carbachol, and nicotine |
|
|
Term
| What occurs in about 1 in every 20,000 persons, causes muscle paralysis because of inability of the neuromuscular junctions to transmit enough signals from the nerve fibers to the muscle fibers? Pathologically, antibodies that attack the acetylcholine receptors. |
|
Definition
|
|
Term
| What allows larger than normal amounts of acetylcholine to accumulate in the synaptic space. Within minutes, some of these paralyzed people can begin to function almost normally? |
|
Definition
| neostigmine-used to treat Myasthenia gravis |
|
|
Term
| What blocks the release of synaptic vesicles, abolishes the serotonin release spikes? |
|
Definition
|
|
Term
| What is a short-lived enhancement of the EPP in response to a brief increase in the frequency of nerve stimulation. One way that this may occur is by a transient increase in the mean number of quanta per nerve stimulus |
|
Definition
|
|
Term
| What is a long-lived and pronounced increase in transmitter release that occurs after a long period of high-frequency nerve stimulation. This effect can last for minutes after the conditioning stimulus. This may be caused by a period of intense nerve firing, which increases [Ca2+]i in the presynaptic terminal and thus increases the probability of exocytosis. |
|
Definition
|
|
Term
| What are found presynaptically where they are peripherally associated with small synaptic vesicles? |
|
Definition
|
|
Term
| Vesicles are targeted to their release sites by ... |
|
Definition
|
|
Term
| Synaptic vesicles are sequestered in... |
|
Definition
| a storage compartment, as well as a releasable compartment |
|
|
Term
| What entry frees vesicles from the storage compartment through phosphorylation of synapsin? |
|
Definition
|
|
Term
What has this...
-Direct receptor-channel coupling
-Neurotransmitter (NT) binding site and the ion channel are intimately associated in a single macromolecular complex |
|
Definition
| Ionotrophic (ligand-gated ion channel) receptor |
|
|
Term
What has this...
-G protein-mediated receptor channel coupling
--Binding of the neurotransmitter (NT) to its receptor R activates a G protein (G), which then interacts with the ion channel causing it to open
-Second messenger-mediated receptor/channel coupling |
|
Definition
|
|
Term
| What is needed to activate the nicotinic AChR? |
|
Definition
| When 2 molecules of ACh bind to the alpa-subunits exposed to the membrane surface, the receptor channel changes conformation. This opens a pore and both sodium and potassium flow through the open channel |
|
|
Term
| The rings at the external and internal surfaces of the cell membrane may serve as...(this is for the AChR) |
|
Definition
|
|
Term
| The central ring of the AChR may contribute to the... |
|
Definition
| selectively filter for cations |
|
|
Term
| What evoked in a muscle cell normally triggers a postsynaptic action potential and contraction of the muscle? |
|
Definition
|
|
Term
| In the absence of nerve stimulation, small depolarizations of 0.5 mV can be recorded, these are called? |
|
Definition
|
|
Term
|
Definition
| spontaneous release of a small amount of ACh |
|
|
Term
| How do EPPs and MEPPS relate? |
|
Definition
| EPP is made up of multiple MEPPS |
|
|
Term
| 1 MEPP= ______ACh molecules |
|
Definition
|
|
Term
| Neurotransmitter release would be described as? |
|
Definition
|
|
Term
| One quantum represents... |
|
Definition
| exocytosis of 1 vesicle and the generation of a MEPP in the postsynaptic muscle cell |
|
|
Term
| What results from 150-200 quanta and is a suprathreshold depolarization? |
|
Definition
|
|
Term
| What equals a measure of all muscle fibers? |
|
Definition
| CMAP (Compound muscle action potential) |
|
|
Term
| What are the keys of a quantal release at the NMJ (Neuromuscular junction)? |
|
Definition
-150-200 quanta released
-Synaptic potential of about 70 mV
-Suprathreshold
SAFETY FACTOR guarantees the muscle fiber reaches threshold |
|
|
Term
| What are the keys of a quantal release at the CNS synapses? |
|
Definition
-most presynaptic neurons produce postsynaptic (PSP) potentials of 0.5 mV
-Some will be inhibitory
-Multiple simultaneous inputs needed to generate an action potential |
|
|
Term
| What are the symptoms of Myasthenia gravis? |
|
Definition
-Eye muscles; drooping of one or both eyelids (ptosis); double vision (diplopia)
-altered speaking
-difficulty swallowing
-problems chewing
-limited facial expressions
-neck and limb muscles
-respiratory muscles |
|
|
Term
What disease causes...
-Reduction in number of VGCC
-Highly organized array of channels is disrupted |
|
Definition
| Lambert-Eaton Myasthenic Syndrome (LEMS) |
|
|
Term
| Antibodies against the presynaptic voltage-gated calcium channels |
|
Definition
|
|
Term
| Antibodies against the postsynaptic AChR |
|
Definition
|
|
Term
| Starts at the extremities and moves up |
|
Definition
|
|
Term
| Starts at the eyes and moves down |
|
Definition
|
|
Term
| Weakness improves with activity |
|
Definition
|
|
Term
| Weakness worsens with activity |
|
Definition
|
|
Term
| Associated with small cell lung cancer |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| Therapy= ACh esterase inhibitors |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| Competitive inhibitor of the AChR |
|
Definition
|
|
Term
| Blocks voltage-gated sodium channels |
|
Definition
| Tetrodotoxin and Saxitoxin |
|
|
Term
| Blocks voltage-gated calcium channels |
|
Definition
|
|
Term
|
Definition
|
|
Term
| Cleaves synaptobrevin / syntaxin, SNAP-25 |
|
Definition
|
|
Term
| AChR agonist; Inactivates end-plate sodium channels; Desensitization of the AChR |
|
Definition
|
|
Term
| Irreversible inhibition of AChE |
|
Definition
|
|
Term
|
Definition
| Botulinum toxin A (Clostridium botulinum) |
|
|
Term
|
Definition
|
|
Term
What drugs does this...
-Weaken nerve to muscle for 4-6 months
-Useful for pts who suffer from abnormal muscle contractions |
|
Definition
| Myobloc (Botulinum toxin B) |
|
|
Term
What are the uses of Clostridial neurotoxins?
Botulinum toxin A (Clostridium botulinum)
Botulinum toxin B |
|
Definition
-Dyastonia
-Cosmetic
-Spasticity following stroke
-Dysphonia
-Hyperhydrosis (blocks nerve to sweat glands) |
|
|
Term
| In Botox what are the purposes of the heavy chain and the light chain? |
|
Definition
heavy chain- facilitates the entry into the synaptic terminal
light chain- protease and cleaves SNAP-25 |
|
|
Term
| What is the result of Botox? |
|
Definition
| Produces flaccid paralysis by preventing the release of ACh at the neuromuscular junction |
|
|
Term
| Botulinum toxin A & E cleaves? |
|
Definition
|
|
Term
| Botulinum toxin C1 cleaves? |
|
Definition
|
|
Term
| Botulinum toxin B, D, F, & G cleaves? |
|
Definition
|
|
Term
What disease...
-Soil spores, animal feces
-Spores germinate and vegetative cells release toxin on lysis
-Toxin passes retrograde along nerve fibers
-Inhibits inhibitory neurons that control the excitability of motor neurons of spinal cord and brainstem
-Trismus (lockjaw) followed by generalized rigidity
-Death by interference with mechanics of respiration |
|
Definition
| Clinical Tetanus (Clostridium tetani) |
|
|
Term
What involves the following...
-Retrograde transport to CNS -30mm/hr
-Inhibits inhibitory glycinergic interneuron
-Hyperexcitation of motor nuerons
-Massive activation of muscle |
|
Definition
|
|
Term
| What is a highly characteristic, abnormal, sustained spasm of the facial muscles that appears to produce grinning? |
|
Definition
|
|
Term
| What is a state of a severe hyperextension and spasticity in which an individual's head, neck and spinal column enter into a complete "bridging" or "arching" position.[1] This abnormal posturing is an extrapyramidal effect and is caused by spasm of the axial muscles along the spinal column. |
|
Definition
|
|
Term
| What is the inability to normally open the mouth due to one of many causes? |
|
Definition
|
|
Term
| Voltage-gated channels open and _______ & __________ ions enter the presynaptic membrane |
|
Definition
|
|
Term
| _________ ions cause __________ ___________ to fuse with the presynaptic membrane |
|
Definition
Calcium
presynaptic vesicles |
|
|
Term
| ____________ is liberated into the synaptic cleft. |
|
Definition
|
|
Term
| The neurotransmitter reacts with ___________ on the muscle membrane. |
|
Definition
|
|
Term
| Channels open and the muscle membrane __________. |
|
Definition
|
|
Term
| This produces an _______ _________ in the muscle membrane. |
|
Definition
|
|
Term
| the neurotransmitter is broken down by ___________ ___________ in the synaptic cleft. |
|
Definition
|
|
Term
| ___________ is taken up into the presynaptic cell? |
|
Definition
|
|
Term
| An isolated nerve-muscle preparation treated with curare would be associated with a decrease in the: |
|
Definition
| Amplitude of MEPPs and Amplitude of EPP |
|
|
Term
| What is the difference between an Electrical synapse and Chemical synapse in terms of Distance between pre- and postsynaptic cell membranes? |
|
Definition
Electrical- 3.5 nm
Chemical- 20-40 nm |
|
|
Term
| What is the difference between an Electrical synapse and Chemical synapse in terms of Cytoplasmic continuity between pre- and postsynaptic cells? |
|
Definition
Electrical- Continuity exists
Chemical- Continuity does NOT exist |
|
|
Term
| What is the difference between an Electrical synapse and Chemical synapse in terms of Ultrastructural components? |
|
Definition
Electrical- Gap-junction channels
Chemical- Presynaptic vesicles and active zones; postsynaptic receptors |
|
|
Term
| What is the difference between an Electrical synapse and Chemical synapse in terms of Agent of Transmission |
|
Definition
Electrical- Ion current
Chemical- Chemical transmitter |
|
|
Term
| What is the difference between an Electrical synapse and Chemical synapse in terms of Synaptic delay? |
|
Definition
Electrical- delay is virtually absent
Chemical- Delay is significant: at least 0.3 ms, usually 1-5 ms |
|
|
Term
| What is the difference between an Electrical synapse and Chemical synapse in terms of Direction of Transmission? |
|
Definition
Electrical- Usually bidirectional
Chemical- Unidirectional |
|
|
Term
| What structural function has a role in Glial cell function and disease? |
|
Definition
|
|
Term
| Structural function of Gap junctions in glial cells? |
|
Definition
| Important for passing small metabolites and ions across the layers of myelin |
|
|
Term
What disease has these characteristics...
-X-linked
-Deymyelination
-Mutation in connexin32 gene expressed in Schwann cells |
|
Definition
| Charcot-Marie Tooth disease |
|
|
Term
| What is the ability of the connection, or synapse, between two neurons to change in strength in response to either use or disuse of transmission over synaptic pathway? |
|
Definition
|
|
Term
| What is the method of signal transduction between neurons, which determines whether or not an action potential will be triggered? |
|
Definition
|
|
Term
| What are the key points of Metabotropic Receptors? |
|
Definition
-Are not ion channels
-Regulate second messenger cascades
- Exert their action through G proteins
-Enzyme systems associated with these receptors can be either upregulated or downregulated
-A great deal of diversity is possible by pairing different receptors with different effector systems |
|
|
Term
| What residues are phosphorylation sites involved with receptor inactivation in the GPCR? |
|
Definition
|
|
Term
| A G protein-coupled receptor contains how many membrane spanning domains? |
|
Definition
|
|
Term
| What is a type of Metabotropic receptor with subtypes including m1,m3,& m5and m2 & m4. |
|
Definition
| Muscarinic acetylcholine receptors |
|
|
Term
| What is the agonist for Muscarinic acetylcholine receptors? |
|
Definition
|
|
Term
| What has a slower onset and a slower offset? muscarine or nicotine |
|
Definition
|
|
Term
| What is the mechanism the muscarinic acetylcholine receptors m1, m3, and m5? |
|
Definition
-Stimulate PI hydrolysis
-Increase intracellular Ca2+
-Increase cAMP levels
-Release arachidonic acid
-Inhibit M-current (K+)
-Activate Ca2+-dependent K+ and Cl- currents |
|
|
Term
| What is the mechanism the muscarinic acetylcholine receptors m2 and m4? |
|
Definition
-Inhibit adenylyl cyclase
-Stimulate inward-rectified K+ current
-Inhibit Ca2+ currents |
|
|
Term
| A single NT can have both a ______ and _______-term effects on an ion channel. |
|
Definition
short- opens or closes the ion channel for a certain period of time
long-repeated exposure can change gene transcription that can result in an altered ion channel, that is always open or always closed. |
|
|
Term
| What is a consequence of multiple receptors for a neurotransmitter:? |
|
Definition
| The activation of different receptors can cause opposite effects on resting membrane potential. |
|
|
Term
| Coactivation of more than one receptor subtype for norepinephrine can result in second-messenger responses, which are... |
|
Definition
1) opposing
2) additive
3) independent |
|
|
Term
| What are the two types of NT Transmission? |
|
Definition
Wired Transmission
and
Volume Transmission |
|
|
Term
| What are the key concepts of Volume Transmission? |
|
Definition
-Release site some distance from target cell
-Neuromodulators
-Range of action limited by diffusion and inactivating enzymes
-Slower onset + longer lasting effects |
|
|
Term
| What can cause cessation of NT action in the CNS? |
|
Definition
-Diffusion
-Reuptake into the synaptic terminal
-Reuptake into glial cells |
|
|
Term
| What is a form of synaptic plasticity which is short-lived and results in increased frequency with no effect on amplitude in the spontaneous postsynaptic potential? |
|
Definition
| Post-tetanic Potentiation |
|
|
Term
| What consists of a high-frequency sequence of individual stimulations of a neuron? |
|
Definition
|
|
Term
| What is a long-lasting enhancement in signal transmission between two neurons that results from stimulating them synchronously? It is one of several phenomena underlying synaptic plasticity, the ability of chemical synapses to change their strength. As memories are thought to be encoded by modification of synaptic strength, this is widely considered one of the major cellular mechanisms that underlies learning and memory. |
|
Definition
| LTP (Long-Term Potentiation) |
|
|
Term
| Describes the reduction in sensitivity of a synapse's response (excitatory or inhibitory) to incoming signals following a tetanus. This is generally caused by a reduction of the amount of neurotransmitters on hand at the synaptic terminal. |
|
Definition
| Post-tetanic depression (Fatigue) |
|
|
Term
| At some synapses depression can last much longer; from minutes to hours, or even several days or months. |
|
Definition
| LTD (Long-Term Depression) |
|
|
Term
| What contacts the terminal of a second presynaptic neuron? |
|
Definition
| inhibitory neurons or facilitating neurons |
|
|
Term
| Release of neurotransmitter by the inhibitory neuron does what? |
|
Definition
| depresses the calcium current, thereby reducing the amount of neurotransmitter released by the presynaptic cell |
|
|
Term
| This results in a depression of the postsynaptic potential (PSP) |
|
Definition
|
|
Term
| Release of neurotransmitter by the facilitating neuron does what? |
|
Definition
| depresses the potassium current in the presynaptic cell, thereby prolonging the action potential and increasing the calcium influx |
|
|
Term
| This results in an increase PSP in the postsynaptic cell |
|
Definition
|
|
Term
| Tell me the 6 events in Presynaptic Facilitation... |
|
Definition
1) Release of serotonin
2) Increase of cAMP activates protein kinase
3) Activation of a protein that phosphorylates potassium channels
4) These channels usually repolarize the membrane following an action potential
5) Prolonged depolarization results in greater influx of calcium
6) Which lead to greater exocytosis of NT
Result: greater response in motot neuron |
|
|
Term
| What are the general principles of Synaptic Integration? |
|
Definition
-Active inputs contribute proportional to their synaptic strength
-Cell bodies sum inputs and scale nonlinearly
-If above threshold, cell fires
-Cell outputs its activity to other neurons |
|
|
Term
| What are the two resistances in a cable? |
|
Definition
-Membrane resistance-
Increases with: decreasing number of open channels and increasing membrane thickness
-Axial or intracellular resistance
decrease with: increasing cross-sectional area |
|
|
Term
| A more leaky cable has... |
|
Definition
-smaller core diameter
-thinner membrane
-short space constant
-slower conduction
-dendrites
-unmyelinated axons |
|
|
Term
| A less leaky cable has... |
|
Definition
-larger core diameter
-thicker membrane
-longer space constant
-faster conduction
-myelinated axons |
|
|
Term
| What is Fast: mediated by ionotropic receptors that pass sodium and potassium ions? |
|
Definition
|
|
Term
| What is Fast: mediated by ionotropic GABA and glycine receptors? |
|
Definition
|
|
Term
| What is associated with NMDA(glutamate receptor) and non-NMDA? |
|
Definition
|
|
Term
| What has a net inward current results in depolarization of the postsynaptic membrane? |
|
Definition
|
|
Term
| What has an increased membrane conductance of chloride? |
|
Definition
|
|
Term
| NT release is _________, so the magnitude of the EPSP is proportional to the amount of NT released. |
|
Definition
|
|
Term
| IPSPs can also be induced by... |
|
Definition
| metabotropic receptors increasing the permeability to potassium ion leading to hyperpolarization of the postsynaptic membrane |
|
|
Term
| The activation of a receptor can set off a cascade that results in... |
|
Definition
|
|
Term
| What synapse is one between the axon of one neuron and the dendrites of another? |
|
Definition
|
|
Term
| What synapse is one between the axon of one neuron and the axon of another neuron? |
|
Definition
|
|
Term
| The similarity in the shape of dopamine and _______ permits this drug to function as a dopamine receptor antagonist. |
|
Definition
|
|
Term
Is this a Therapeutic effect or a Side effect?
Mediated by different types of receptors |
|
Definition
| Side effects=TOXIC response |
|
|
Term
Is this a Therapeutic effect or a Side effect?
Mediated by identical receptors but in different tissues or by different effector pathways |
|
Definition
|
|
Term
Is this a Therapeutic effect or a Side effect?
Mediated by same receptor-effector mechanism |
|
Definition
|
|
Term
What is this called...
Drugs can increase rate of synthesis of NT receptors resulting in an increased sensitivity to neurotransmission. |
|
Definition
|
|
Term
| What is this called...drugs acting at a receptor can affect the number of NT receptors by decreasing the rate of synthesis? |
|
Definition
|
|
Term
| What is a circuit for spreading stimulation to multiple neurons or neuronal pools? |
|
Definition
|
|
Term
| What is a circuit providing input to a single neuron from multiple sources? |
|
Definition
|
|
Term
| What neurons function in a sequential manner? |
|
Definition
|
|
Term
| What neuronal circuit has information that is processed simultaneously? |
|
Definition
|
|
Term
| What neuronal circuit has a feedback mechanism that may be excitatory or inhibitory? |
|
Definition
|
|
Term
| What effect will replacing calcium ions in the bathing medium with cobalt ions have on the EPSP and ACh response? Why? |
|
Definition
Replacing calcium ions with cobalt ions in the bathing medium would block the EPSP but not the ACh response.
Calcium entry into the presynaptic terminal through VGCC (which are blocked by cobalt) is necessary for transmitter release and thus an EPSP, but no calcium is necessary for the ACh response. |
|
|
Term
| 2. What effect will injection of the presynaptic terminal with botulinum toxin have on the EPSP and the ACh response? Why? |
|
Definition
| Injecting the presynaptic terminal with botulinum toxin will block the EPSP because it interferes with the mechanism of release of transmitter vesicles (enzymatic cleaving of the vesicle associated membrane proteins: synaptobrevin / syntaxin, SNAP-25) |
|
|
Term
| What effect will physostigmine to the bathing medium have on the ESPS and the ACh response? Why? |
|
Definition
| Physostigmine will augment and prolong the EPSP and the ACh response, because it prolongs the lifetime of acetylcholine at the postsynaptic ACh receptors by blocking enzymatic degration. |
|
|
Term
| What effect will curare to the bathing medium have on the ESPS and the ACh response? Why? |
|
Definition
| Curare will block (or at least reduce) both the EPSP and the ACh response, because it will block (or at least partially block) the postsynaptic ACh receptors. |
|
|
