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42 Cards in this Set
- Front
- Back
Synaptic transmission
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Process of information transfer at a synapse
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Electrical synapse
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Electrical current from one neuron to the next (Edward Furshpan and David Potter)
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Chemical synapse
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Otto Loewi. Frog experiment.
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Gap junctions
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Where electrical synapses occur (specialized sites). The membranes of two cells are separated by only about 3nm, and this narrow gap is spanned by clusters of special proteins called connexins.
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Gap junction channel
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Allos ions to pass directly from the cytoplasm of one cell to the cytoplasm of the others. The pore of most gap junctions is relatively large.
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Postsynaptic potential (PSP)
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When 2 neurons are electrically coupled, an action potential in the presynaptic neuron causes a small amt of ionic current to flow across the gap junction channels into the other neuron.
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Secretory granules
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Larger vesicles about 100 nm in diameter. Contain soluble protein that appears dark in the electron (dense-core vesicles)
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Membrane differentations
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Dense accumulations of protein adjacent to and within the membranes on either side of the synaptic cleft
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Active zones
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Actual site of neurotransmitter release
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Postsynaptic density
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Protein thickly accumulated in and just under the postsynaptic membrane
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Neuromuscular junction
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Chemical synapses that occur between the axons of motor neurons of the spinal cord and skeletal muscle.
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Glu, GABA, Gly, ACh
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Amino acids that mediate fast synaptic transmission at most CNS synapses
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Transporters
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Special proteins embedded in the vesicle membrane. Concentrate neurotransmitters inside the vesicle.
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Voltage-gated calcium channels
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Opened in active zone by depolarization of the terminal membrane. Large inward driving force of Ca2+
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Exocytosis
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Vesicles release their contents into synaptic cleft.
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Endocytosis
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Recovers vesicle membrane and recycles vesicle (filled again with neurotransmitter)
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Transmitter-gated ion channels
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Receptors are membrane spanning proteins consisting of four or five subunits that come together to form a pore between them. Without neurotransmitter, pore is usually closed. When NT present, slight twist = open
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Excitatory Post Synaptic Potential (EPSP)
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A transient postsynaptic membrane depolarization caused by the presynaptic release of neurotransmitters
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Inhibitory Post Synaptic Potential (IPSP)
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A transient hyperpolarization of the postsynaptic membrane potential caused by the presynaptic release of neurotransmitter
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Autoreceptors
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Presynaptic receptors that are sensitive to the neurotransmitter released by the presynaptic terminal
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Second messengers
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Enzymes that synthesize molecules
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Metabotropic Receptors
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Protein-coupled receptors that trigger widespread metabolic effects
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Neuropharmacology
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Study of the effects of drugs on nervous system tissue
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Inhibitors
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Proteins that inhibit the normal function of receptors
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Receptor antagonists
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Inhibitors of neurotransmitter receptors
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Receptor agonists
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Mimic actions of naturally occurring neurotransmitter
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Nicotinic ACh receptors
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the ACh-gated ion channels in muscle receptors
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Synaptic integration
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Process by which multiple synaptic potentials combine within one postsynaptic neuron
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Mini PSP
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Exocytosis can occur without presynaptic stimulation leading to a slow release of neurotransmitter. The response from the postsynaptic cell = mini
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Quantal analysis
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A method of comparing the amplitudes of minis and evoked postsynaptic potentials = determine how many vesicales release neurotransmitter during normal synaptic transmission
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EPSP Summation
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The simplest form of synaptic integration in the CNS. There are 2 types, spatial and temporal
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Spatial summation
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Adding together of EPSPs generated simultaneously at many different synapses on a dendrite.
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Temporal summation
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Adding together of EPSPs generated at the same synapse if they occur in rapid succesion, wihtin about 1-15msec of one another
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Length constant
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The distance (lambda) where the depolarization is 37% of that at the origin
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Internal resistance
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the resistance to current flowing longitudinally down the dendrite (r[i])
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Membrane resistance
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The resistance to current flowing across the membrane
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Shunting inhibition
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Prevents the current from flowing through the soma to the axon hillock
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Modulation
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A synaptic transmission that modifies the effectiveness of EPSPs generated by other synapses with transmitter-gated ion channels.
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Norepinephrine (NE)
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Amine neurotransmitter
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Adenylyl Cyclase
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Catalyzes the chemical reaction that converts ATP into cAMP
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Protein Kinases
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Catalyze a chemical reaction called phosphorylation.
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Phosphorylation
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The transfer of phosphate groups from ATP to specific site on cell proteins.
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