LG 2.3 Electrophysiology of Neurons Flashcards
What are EPSP?
- Excitatory post synaptic potential
- Synaptic inputs that depolarize the postsynaptic cell.
What channels are normally involved with EPSP?
Produced by opening potassium and sodium channels
What neurotransmitters are normally involved with EPSP?
-Ach, norepinephrine, epinephrine, dopamine, glutamate, and serotonin
What are IPSP?
- Inhibitory post synaptic potential
* Hyperpolarize cell membrane
What channels are normally involved with IPSP?
- Opening of Cl- channels
What neurotransmitters are normally involved with IPSP?
GABA and Glycine
What are the types of synaptic arrangements (number) ?
- One-to-one (neuromuscular junction)
- One-to-many
- Many-to-one
What are the types of synaptic arrangements (location)?
- Presynaptic Inhibition
- Axosomatic synapses
- Axodendritic synapses
What is the main excitatory neurotransmitter?
Glutamate
What types of receptors does Glutamate have?
Four subtypes of receptors
•3 are Ionotropic
-AMPA, NMDA
•Metabotropic
What reuptakes glutamate?
Glia cells
What are defining features of seratonin receptors?
- Direct gating of cation channel (5-HT3, excitatory)
* G-protein coupled effects on K+ channel (5-HT1-2, 4-7, excitatory and inhibitory
What is the Length Constant?
- Decay over distance
* Membrane resistance and internal (longitudinal resistance)
What is long term potential?
It is a persistent increase in synaptic strength following high-frequency stimulation of a chemical synapse. Studies of LTP are often carried out in slices of the hippocampus, an important organ for learning and memory.
What is long-term depression?
It is an activity-dependent reduction in the efficacy of neuronal synapses lasting hours or longer following a long patterned stimulus. LTD occurs in many areas of the CNS with varying mechanisms depending upon brain region and developmental progress.
What is Hyperkalemia?
- Increase in K+ in the extracellular space.
- Membrane depolarization.
- Voltage-gated Na+ channels remain inactivated if the cell is not allowed to hyperpolarize.
What does Hypocalcemia cause?
•Increase in excitability of nerve and muscle cells
What does hypercalcemia cause?
•Depresses neuromuscular excitability
What does Hypoxia do to the cell?
- Hypoxia results in the Na+ staying in the cell. This depolarizes the membrane and also draws water into the cells.
- The Na+/K+ ATPase maintains the gradients of Na+ and K+.
- The pump requires ATP. Oxygen is required to produce the ATP.
- Without oxygen, the pump is shut off.
What are channelopathies?
- Genetic mutations in ion channels.
* Nearly all types of ion channels have been shown to be susceptible.
What channelopahties can cause paralysis?
Sodium/Calcium/Potassium channel defects
What channelopathies can cause ataxia?
KCNC3 Potassium channel defect
What channelopathies can cause night blindness?
Calcium
