Week 2 - Trachte Flashcards
What are the two general types of Ionic Channels in neurons?
-
Voltage-gated: ion channels open due to voltage of the membrane
- Na+
- Ca2+
-
Ligand-gated: ion channels open when a ligand binds to the receptor
- Glutamate
- GABA
- Serotonin (5HT)
- Nicotinic
What are typically the two types of neurotransmitter receptors?
- Ligand-gated channel
- Metabatropic receptors
When are ligand-gated channels neurotransmitter receptors?
Used for fast action potential and only open briefly
How do metabatropic receptors act/fxn as neurotransmitter receptors?
- Receptor interacts with a GTP-binding protein (7 transmembrane protein) → leads to G-protein cascade
- Effects voltage-gated ion channels by affecting membrane potential
- Typically inhibitory → will hyperpolarize by enhancing K+ (pushing more out) or inhibiting Ca2+ (not letting in)
What are the basic steps in chemical transmission of a synapse (synaptic potentials)?
- Action potential comes down the axon →
- depolarizes presynaptic membrane →
- voltage-gated Ca2+ channels open →
- Ca2+ enters presynaptic neuron and promotes docking of vesicles →
- vesicles fuse with membrane and release NT into synaptic cleft →
- NT binds to postsynaptic receptor →
- postsynaptic membrane potential is changed to either stimulate another action potential (depolarization/excitatory) or inhibit another action potential (hyperpolarization/inhibitory)
What is the MOA of Lidocaine?
- block Na+ channels and inhibits action potential conduction to axon terminal
- prevent ionic conduction
What drugs intervene at 1-9?
- Action potential conductance
- Synthesis of NT
- Storage of NT
- Metabolism of NT
- Release of NT
- Uptake of NT
- Degradation of NT
- Receptor Interference
- Ionic conductance
- Lidocaine
- DOPA (Al-dopa)
- ***
- Monamine oxidase inhibitors
- Methamphetamine
- SSRI/Cocaine
- Anticholinesterase
- Receptor antagonist
- Lidocaine
What is the MOA of Reserpine?
depletes storage of norepinephrine
What is the MOA of Monamine Oxidase Inhibitors?
Prevents breakdown/metabolism of monoamines (ex: dopamine) to increase level of NT
What is the MOA of Methamphetamine?
Increases amount of NT released into cleft
What is the MOA of Cocaine?
Prevents the reuptake of NT from the cleft (increases NT levels in the cleft).
(also MOA of SSRI’s)
What is the MOA of Anticholinesterase?
Prevents the breakdown of ACh (increases levels in the cleft).
What is the MOA of Receptor Antagonists/Agonists?
Can be used to antagonize (prevent function) or agonize (increase function) receptor function.
What does it mean when neuronal systems are “Hierarchial Systems”?
- Aligned in order almost linearly
- ex. sensory perception
- ex. motor control
What does it mean when neuronal systems are “Diffuse Systems”?
- Not highly ordered → affect many different regions of the brain by diffusion of NT (is a slutty NT and binds to any receptor it can reach)
- Has a more generalized effect
- Ex: dopamine, norepi
