Ionotropic and Metabotropic Neurotransmission Flashcards
Synaptic Transmission
chemical means by which neurons communicate with each other
A. Where are neurotransmitters released from?
B. What is the space between membranes involved in transmitter release called?
C. What do the receptors in postsynaptic membranes generate?
A. The vesicles in the presynaptic membrane
B. Snaptic cleft
C. Postsynaptic potentials
1In ionotropic gated transmission receptors are…
2 Ionotropic gated transmission is transient or lasting?
1transmitter/ligand gated channels
2. transient (10-20 milliseconds)
In ionotropic gated transmission binding with a neurotransmitter changes its configuration to increase or decrease its permeability to ions
increases
The net effect of EPSP is polarization or depolarization? Why? What ions are involved?
Increase in permeability of Na+ and K+. Na+ enters (depolarizes) cell and K+ exits (polarizes). Higher concentration of Na+ outside cell results in overall depolarization
What is an excitatory action?
The membrane depolarizes closer to threshold of action potential, this increasing the excitability
Where do excitatory synapses normally occur?
on dendrites
The net effect of an IPSP is polarization or depolatization? Why? What ions are involved?
Hyperpolarization is caused by influx of Cl- and efflux of K+ ions.
What is an inhibitory action?
THe membrane hyperpolarizes away from the threshold, decreasing excitability
Where are inhibitory synapses usually found?
on cell bodies
What is spatial summation of psp’s?
Simultaneous activation of EPSPs in different regions of the cell
What is temporal summation?
the summation of synaptic potentials from the same synapse can summate to create overall excitation or inhibition
Define excitation
The summated EPSPs can approach and exceed the threshold for action potentials
Define inhibition
Summated IPSPs can pull membrane away from the threshold, decreasing the likelihood that an action potential will be initiated
How many axons can synapse upon a single neuron
thousands
What does EEG measure?
The synchronization of PSPs among large populations of neurons
What type of information is processed in dendrites and cell bodies?
Postsynaptic potentials (analog” information… enough or not enough to create AP)”
What type of information is processed at the axon hillock?
AP initiation
What type of information is processed at the Axon?
AP conduction (digital” information)”
What type of information is processed at the axon terminals?
Synaptic release
Non-gated channels: What type of ions are involved and where are the channels located?
THey are K+ channels
Located along the whole cell, except initial segment and nodes of Ranvier
Voltage gated channels: What type of ions are involved and where are the channels located?
- Na+ and K+ channels- located at the initial segment and nodes of Ranvier (APs)
- and Ca++ channels- located at axon terminal (transmitter release)
Neurotransmitter/ligand gated: What type of ions are involved and where are the channels located?
- Na+/K+ channels- located at Postsynaptic dendrite membranes (EPSPs)
- Cl- channels- located at postsynaptic cell body membrane (IPSPs)
- Metabotropic gated transmission does or does not penetrate membrane?
- Its effect is lasting or transient?
- Does not
2. Lasting (minutes to hours)
