Term
| What are the inhibitory ionotropic receptors? |
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Definition
GABA+Gly
Usually use Cl- as neurotransmitter (Na/Ca/K for gates) |
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Term
| What are the excitatory ionotropic receptors? |
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Definition
Ach (use Na/K channels, pentameric)
Glu (use Na/K/Ca) - Tetrameric |
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Term
| How many neurons does the brain have? How many connections? |
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Definition
| 10^11-10^12 and may receive 10,000 synaptic inputs. 10^15 connections. |
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Term
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Definition
| Central Neuron - Excitatory vs inhibitory. Central neurons use a variety of neural transmitters, non-integrating NMJ uses only Ach. Safety factor is low in central neurons. Central neurons can be ionotropic or metabotropic. |
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Term
What corresponds to these three synapses:
Excitatory, Inhibitory, Modulatory |
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Definition
Excitatory: Axodendritic
Inhibitory: Axosomatic
Modulatory: Axo-axonic |
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Term
| Ultrastructural differences of inhibitory and excitatory synapses |
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Definition
| Synaptic vessicles on presynaptic terminals of inhibitory synapses usually have a flattened shape. |
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Term
| Polarity of a synapse depends on? |
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Definition
| Postsynaptic receptors (same neurotransmitter can be excitatory or inhibitory) |
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Term
| Axoaxonic synapses are commonly involved in what? |
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Definition
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Term
| Presynaptic Inhibition Sources |
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Definition
| Axoaxonic input may produce an IPSP in the presynaptic terminal. The axoaxonic input may produce a slow, small EPSP that inactivates Na+ channels. |
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Term
| Metabotropic Synaptic Receptors |
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Definition
| Gate ion channels indirectly. Second messengers cause open or close. Typically found at modulatory axoaxonic synapses. |
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Term
| Common EPSP producing trasmitter in CNS? |
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Definition
| Glutamate Depolarization dependent on number of glu channels opened. |
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Term
| What receptor normally plays a role in fast epsp's? |
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Definition
| Non-NMDA receptors. Also, they are not permeable to divalent cations! |
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Term
| What channels are blocked by extracellular Mg2+? |
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Definition
| NMDA. They are also permeable to calcium. Also, reason there is little contribution of NMDA receptors to EPSP at negative voltages (as opposed to late phase current). |
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Term
Antagonists of NMDA receptors?
non-nmda? |
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Definition
APV, PCP, MK801. Affect late phase current.
non-nmda: CNQX |
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Term
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Definition
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Term
| Non-NMDA and NMDA produces an EPSP that decays more slowly than an EPSP produced by opening on non-NMDA receptors alone. |
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Definition
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Term
| Late phase is characterized by? |
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Definition
| Calcium entering postsynaptic neuron through open NMDA channels. |
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Term
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Definition
| High frequency stimulation of NMDA channels (probably by cooperative action of multiple afferent neurons). Associative Hebbian learning may occur with multiple APs (more Ca and more enzymatic signaling). |
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Term
AMPA receptors - four genes
Kainate - three low-affinity subunits and 2 high affinity
NMDA receptors - seven genes. |
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Definition
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Term
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Definition
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Term
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Definition
Result from activation of postsynaptic receptors that increase K+ or Cl- conductance (most). First is metabotropic (GabaB and Muscarinic Ach receptors). Second is Ionotropic (GabaA and Gly receptors).
IPSPs in brain - GABA, spinal cord - Gly |
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Term
| GabaA receptors pharmacologically opened by what substances? |
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Definition
| Valium, Librium, Barbituates. Ethanol and general anesthetics. |
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Term
| Properties of GABA and Gly Receptors (inhibitors?) |
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Definition
GABA - brain. Gly - Spinal cord. Inhibition of GabaA: Benzodiazapines, Barbituates, Ethanol, General Anesthetics, Bicuculline.
Glycine Receptor Inhibitors- Strychnine. |
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Term
Diseases of Receptors:
Glu
Ach
GabaA
Gly |
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Definition
Glu: Domoic acid. Intoxication by MSG. Ischaemic neuronal death. Neurodegeneration.
Ach: Nocturnal frontal lobe epilepsy
GabaA: Angleman, Jevenile myoclonic epilepsy
Gly: Startle |
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Term
| Decision to fire or not fire an AP is made where? |
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Definition
| The axon Hillock (threshold is lowest here). |
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Term
| What is best for temporal summation? |
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Definition
| A slow time constant (high membrane resistance and membrane capacitance). |
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Term
| What is shunting inhibition? |
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Definition
| An inhibitory synapse may conduct a shunt and the EPSP is attneuated. |
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Term
| What is Subtraction inhibition? |
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Definition
| When a EPSP and IPSP meet near the axon hillock. |
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