Flashcards
Synaptic Transmission
Cards in this deck (26)
- 1Direct transmission occurs at- electrical synapses
- chemical synapses with ionotropic receptors - 2Indirect transmission occurs atchemical synapses with metabotropic receptors
- 3Electrical synapses characteristics- less common in the vertebrate brain
- lack of synaptic vesicles
- connects two cells with gap junctions
- mediated by connexons
- no synaptic delay - 4connexonsmolecules with 6 subunits
- pore that passes through both membranes and allows ion flow - 5electrical synapses are more reliable than chemical synapses- found in pathways related to escape reflexes
chemical synapses can fail due to synaptic depression - 6chemical synapses can be studied atneuromuscular junction
- 7reversal potential Erev\the voltage at which there is no current flow for a channel that lets through more than one ion
- 8How to determine which ions flow through the nAChR- radioactive isotopes uptake in postsynaptic membrane
- changing the concentration of ions in the bath - 9nAChR is selective forcations and allows Na+, Cl-, and K+ to flow through
- 10Size of PSP in chemical synapses depend on- reversal potential
- number of channels
- resting conductance through leak channels - 11Reversal potential of a channel- constant
- depends on selectivity and driving forces on the ions (usually doesn't change) - 12how number of channels open affect size of PSP- inc channels bc inc amt of transmitter by inc number or duration of AP in presynaptic cell
- 13how resting conductance through leak channels affect size of PSPkeeps cell close to resting membrane potential
- close-> inc magnitude of EPSP - 14direct synaptic excitationopen channels whose reversal potential is positive to threshold
- 15direct synaptic inhibitionopen channels whose reversal potential is negative to threshold
- generally opens Cl- selective channels (or sometimes K+) - 16presynaptic inhibitionwhen a synapse causes a decrease in the amount of transmitter released
- 17presynaptic excitationexcitatory transmitter released onto presynaptic terminal depolarizes terminal and inc amount of transmitter
- 18indirect synaptic transmissionchemical synapses with metabotropic receptors
- 19Metabotropic receptors activateG proteins-> activate second messenger pathways-> open or close ion channels
- 20G protein coupled metabotropic receptors physical properties7 membrane crossing regions
- extracellular amino terminus
- intracellular carboxy terminus - 21when a neurotransmitter binds to a GPCRGDP-> GTP on alpha subunit
- 22activated G proteins candirectly affect ion channels
- ex. muscarinic AChR-> Beta and gamma subunit activates K+ channel and slows heart rate - 23G proteins can work through second messenger cascadesex. norepinephrine and beta-adrenergic receptors-> increase heart rate
- 24Second messenger cascade- activated G-protein subunits activate adenyl cyclase
- converts ATP to cAMP
- cAMP activates other protein kinases to phosphorylate Ca+ channels
- inc probability of channels opening - 25G proteins and other signaling pathways- activate phospholipase C
- hydrolyze PIP2 into IP3 and DAG
- phosphorylates Ca+ channels
or
- activae A2 and indirectly activate PKC - 26learning and memoryeffects of metabotropic receptors are slower but longer lasting than effects of ionotropic receptors
- second messenger cascade is slow, but can alter gene expression
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- NPB 110B Neurobiology (Midterm 2) Flashcards on Synaptic Transmission, created by Jessica Collado on 10/05/2020.
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- Jessica Collado
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