Neurotransmission Flashcards
describe EPSP
EPSP- excitatory postsynaptic potential, results in depolarization by allowing (+) ions in or (-) ions out
describe IPSP
IPSP- inhibitory postsynaptic potential, results in hyper polarization by allowing (-) ions in or (+) ions out
what is GABA?
inhibitory neurotransmitter that binds to GABA receptors which are ligand gated Cl- channels
what does it mean that postsynaptic potentials are “graded”?
graded potential means that the amplitude varies secondary to the amount of neurotransmitter released from the pre synaptic terminal
what is the length constant
calculation of how far post-synaptic potentials are conducted
what factors influence the length constant?
rm (membrane resistance) - directly prop
ri (internal resistance)- indirectly prop
what is the effect of myelin on rm?
myelin increases Rm, thereby increases length constant
what is the effect of narrow axon vs. wide axon on length constant?
wide axon will have decreased Ri and increased length c
narrow axon will have increased Ri and decreased length c
what is “integration” of post-synaptic potentials?
integration is the accounting of excitatory and inhibitory signals to decide if an action potential will be produced or not
what is temporal summation?
multiple inputs from a single source
what is spatial summation?
multiple inputs from multiple sources
where is the first place the AP is generated?
just distal to the axon hillock
where are Na channels concentrated on myelinated nerves?
at the nodes of ranvier
what is the effect of myelination on conduction speed?
myelination increases conduction velocity
how does fiber diameter relate to AP conduction speed?
directly prop, increase fiber width, increase velocity
what is the effect of demyelinating disease (MS)?
decreased AP velocity, blocked conduction
what is potential MS treatment?
K channel blockers to prolong depolarization and help AP conduction
how do local anesthetics work?
local anesthetics are Na channel blockers that decrease the initiation an conduction of AP in sensory neurons
how are neurotransmitters released into synaptic cleft?
depolarization of the presynaptic terminal allows for Ca influx and this triggers release of NT from vesicles
what are some qualities of NT vesicles?
low pH, require active transport of NT into vesicles
what are mechanisms of termination for nerve terminal conductance?
reuptake of NT into presynpatic terminal, inactivation of NT, degradation of NT in cleft
what drugs target GABA Receptor?
propofol, ethanol, benzos, volatile anesthetics
what NTs use monoamine receptors?
norepinephrine, dopamine, serotonin
what is the function of SSRI?
inhibits reuptake of serotonin into presynaptic terminal, increases concentration in the cleft
