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76 Cards in this Set
- Front
- Back
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One action potential in the motor nerve normally leads to ? action potential across the muscle membrane.
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1
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The number of transmitter molecules released by one exocytosed vehicle is called a...?
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quantum
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total number of quanta released when the synapse is activated is called...
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quantum content
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quanta are fixed in sized or variable?
Quantum content is fixed or variable? |
fixed in size
variable |
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The transmission of information at chemical synapses involves ? (4 steps)
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Release of Neurotransmitter
Diffusion across synpatic cleft Binding of neurotransmitter to receptor Change in membrane potent. |
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What are the 3 criteria are used to formally designate a substance as a neurotransmitter.
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Synthesized in Presynaptic Cell
Released by Presynaptic Cell Response of Postsynaptic cell must mimic in vivo response |
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Neurotransmitter Substances can be broken down into what 4 categories?
(BANC) |
Choline Esters
Biogenic Amines Amino Acids Neuropeptides |
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Name the 5 Biogenic Amines for Neurotransmitters
NSHED |
norepinephrine
serotonin histamine epinephrine dopamine |
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Name 2 Amino Acids for Neurotransmitters
(3G) |
GABA
Glutamate Glycine |
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Name an Choline Ester for Neurotransmitters
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Acetylcholine
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Where is the synthesis of the enzyme for making transmitter done in the cell?
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At the cell body
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The enzymes are transported from the cell body to the nerve endings by a process called...
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Axoplasmic Transport
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If a person were to inhibit axoplasmic transport what would happen?
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Inhibitory effects on synaptic transmission
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What is the ONLY neurotransmitter that is utilized at the NEUROMUSCULAR JUNCTION
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ACh
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True or False
All preganglionic and All postganglionic neurons in the parasymp. nervous system release ACh. |
FALSE
All preganglionic Most postganglionic parasympth nervous system |
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True or False
All Preganglionic neurons and Most Postganglionic neurons in the sympathetic nervous system release ACh. |
FALSE
ALL preganglionic release NO postganglionic neurons release |
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Adrenal medulla releases ? from presynaptic neurons.
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ACh
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Nicotinic ACh receptors are found in skeletal muscles and are what type of channels?
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Ligand-Gated Na+/K+ channels
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Muscarinic AChreceptors are found in cardiac muscle and are what type of receptor.
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G-Protein Coupled Receptor
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ACh is made with what enzyme and parts?
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Choline
Acetyl CoA Choline Acetyltransferase |
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Approximately ? of the choline that is released from the degradation of ACh is taken back into the ?
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50%
Presynaptic Terminal |
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If a patient as MYASTHENIA GRAVIS and is administered an anesthetic what can possible happen?
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Anesthetic = nondepolarizing muscle relaxant
blocks ACh receptors leads to temporary paralysis and lack of breathing |
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What relaxant can be used that does not affect MYASTHENIA GRAVIS patients?
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SUCCINYLCHOLINE
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In Spinal Muscular Atrophy (SMA) and Amyotrophic Lateral Sclerosis (ALS) what happens to the muscle cell receptors?
What happens if Succinylcholine is given? |
Increase of New ACh receptors
Due to loss of motor nerves heart stops due to K+ efflux into serum |
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What does Succinylcholine do to cells?
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Causes K+ channels to open
raising Serum K+ levels |
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A defect in ryanodine receptors seen in Malignant Hyperthermia does what?
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prevents calcium uptake into SR.
Can cause persistent contraction and elevated temperature |
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Diisopropyl phosphorofluroidate (DFP) are an anticholinesterase that do what?
causing what? |
severly inhibit AChE causing ACh molecules to persist in synaptic cleft
muscle contractions / paralysis / death |
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Organophosphates in the somatic nervous system can block ? that leads to acetylcholine buildup
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Acetylcholinesterase
AChE |
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ACh effects glands due to its interaction with which nervous system?
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Autonomic Nervous System
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Patient has signs of excess bronchial secretion, drooling, and tearing of the eyes. What would be administered for treatment?
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Atropine
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Atropine blocks what type of receptors?
What symptoms would you look for when administering ACh? |
Muscarinic Receptors
SLUDGE -Salivation -lacrimation -urination -diaphoresis (sweaty) -gastrointestinal motility -Emesis (vomiting) |
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In what synapses would you find catecholamines in?
Name the catecholamines |
Adrenergic Synapses at junctions between NERVES & SMOOTH MUSCLE or NERVE to NERVE in the brain
Dopamine norepinephrine epinephrine |
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What is precursor molecule for norepinephrine, epinephrine, and dopamine?
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Tyrosine
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Describe the biosynthetic pathway in use with Tyrosine.
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Tyrosine / tyrosine hydroxylase
--> L-Dopa / dopa decarboxylase -->Dopamine / dopamine β-hydroxylase -->norepinephrine / PNMT -->epinephrine |
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The type of neurotransmitter secreted depends on ?
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the enzymatic pathway that is present in that particular nerve/gland.
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Dopaminergic neurons would most likely have what enzymes to make dopamine?
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Tyrosine Hydroxylase
Dopa Decarboxylase |
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Adrenergic neurons would secrete norepinephrine because they contain what enzymes?
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Tyrosine Hydroxylase
dopa decarboxylase Dopamine- β-hydroxylase |
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Adrenal medulla contains the complete enzymatic pathway and PNMT allowing it to secrete?
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epinephrine
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Degradation of dopamine, norepinephrine, and epinephrine occurs via what 2 enzymes?
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Catechol-O-methyltransferase (COMT)
Monoamine Oxidase (MAO) |
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What methylating enzyme is NOT found in nerve terminals for degradation?
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Catechol-O-methyltransferase
(COMT) |
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PRESYNAPTIC nerve terminal enzyme that catalyzes oxidative deamination.
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Monoamine Oxidase
(MAO) |
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how many possible degradative products from each neurotransmitter using COMT and MAO?
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three possible products
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Major metabolite of norepinephrine degradation is?
(COMT) |
Normetanephrine
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Major metabolite of epinephrine degradation is?
(COMT) |
Metanephrine
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Norepinephrine and epinephrine are both degraded by MAO+COMT to..?
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3-methoxy-4-hydroxymandelic acid (VMA)
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If Serotonin is used as a neurotransmitter in the CNS what does it do?
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Excitatory neurotransmitter
INDIRECTLY closes K+ channels |
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What is the precursor molecule of Serotonin?
enzyme used for conversion? Where is it made? |
Tryptophan
tryptophan hydroxylase Brain Gastrointestinal Tract |
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What happens to Serotonin after it has been released?
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Return INTACT to nerve terminal
DEGRADED in the presynaptic terminal by MAO |
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What is Serotonin degraded to by MAO?
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5-Hydroxyindoleacetic Acid
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Serotonin is a precursor to ? in the pineal gland
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Melatonin
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Blocking reuptake of serotonin is commonly used in?
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antidepression drugs
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Hitasmine is synthesized from?
catalyzed by what enzyme? found where? |
Histidine
Histidine Decarboxylase hypothalamus & non-neural tissue (mast cells) of gastrointestinal tract |
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An amino acid that is the MAJOR excitatory neurotransmitter in the CNS
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Glutamate
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Name 4 subtypes of glutamate receptors.
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Ionotropic rec`eptors
N-Methyl-D-aspartate (NMDA) receptor metabotropic receptors AMPA |
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Predominate Glutamate receptors in the CNS (2)
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AMPA receptors
NMDA receptors |
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Stimulation of AMPA receptors by glutamate causes?
NMDA receptors? |
EPSP due to flow of Na+ and K+ flow
EPSP due to flow of Ca+ and K+ flow. |
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NMDA receptors are blocked by extracellular ? at physiological levels
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Mg2+
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Glutamate acts on AMPA receptors --> causes depolarization of the postsynaptic cell reliving the Mg2+ block of ? receptors leading to ? influx
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NMDA receptors
allows Ca2+ |
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Glutamate is turned into GABA through enzyme catalyst?
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Glutamic Acid Decarboxylase (GAD)
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An amino acid INHIBITORY neurotransmitter found in the spinal cord and brain stem. Increases Cl- Conductance of the postsynaptic cell membrane.
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Glycine
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Once GABA is secreted, it can either be recycled or degraded by ?
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GABA transaminase
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Out of the 3 amino acid neurotransmitters, which does not have any metabolic function?
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GABA
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Benzodiazepines and Barbiturates affect GABA(A) receptors in the ? system
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Central Nervous System
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GABA(B) receptors are metabotropic and when stimulated they activate G-protein that does what?
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Increase K+ conductance and hyperpolarizes the postsynaptic cell
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Huntington's disease is characterized by uncontrolled movements due to lack of ?
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GABA-dependent inhibition of neural pathways
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metabolites from degradation of GABA are used in the ?
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Citric Acid Cycle
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Short -Acting Inhibitory neurotransmitter in the GI tract and CNS
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Nitric Oxide
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Nitric Oxide is synthesized in the presynaptic cleft by ? from what precursor molecule?
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NO synthase
Arginine |
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Neuropeptides can function as what 3 things?
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Neuromodulators
Neurohormones Neurotransmitters |
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Substances that act on the presynaptic cell alter the amount of neurotransmitter released in response to stimulation.
Can be co-secreted with a neurotransmitter and alter response of postsynaptic cell to the neurotransmitter |
Neruomodulators
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Hormones that are secreted by neurons into the blood to act at a distant site.
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Neurohormones
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True or False
Neuropeptides can be co-packaged and co-secreted from presynaptic vesicles |
True
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neurotransmitters are synthesized where?
neuropeptides are synthesized where? |
Presynaptic Nerve Terminals
Nerve Cell Body |
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how are neuropeptides transported from the cell body to presynaptic terminal?
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Axonal Transport
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As extracellular [Ca2+] rises what will happen in neurotransmitter release?
Decrease? |
high [Ca2+] --> increase # of vesicles released
low [Ca2+] -> decrease # of vesicles released |
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As extracellular [Mg2+] increases what will happen in neurotransmitter release?
decrease? |
high [Mg2+] -> decrease # of vesicles released
low [Mg2+] -> increase # of vesicles released |
