Nerve Muscle Synapse Lecture 4 Flashcards
Where would you find neurotransmitters?
in vesicles within the pre-synaptic terminals
Receptors on the post-synaptic cell are also ____ channels
Ion
What type of synaptic transmission do most of the systems we talk about use?
Directly Gated
Neurotransmitters can be ____\_or _____\_
Neurotransmitters can be excitatory or inhibitory
afferent neurons use the excitatory neurotransmitter:
glutamate
An interneuron can be either _____ or _____ but not both!
excitatory or inhibitory
The space between the post-synaptic and pre-synatic cell is called:
The synaptic cleft
An excitatory nt will have what effect?
Open up Na+ ion channel = Na+ flows through (into the cell making cell more positively charged) = depolarization in membrane of postsynaptic cell = EPSP
What will be the effect on the post-synaptic cell if an inhibitory NT (___ or ___) binds?
What will be the effect on the post-synaptic cell if an inhibitory NT (Cl- or K_+_) binds?
Cl- or K+ channel opens = inside of cell becomes more negative (K+ will leave OR Cl- will enter) = IPSP
In the post synaptic cell, what is generated is NOT an AP. If depolarization occurs we will see either an _____ (excitatory) or _____ (inhibitory)
EPSP - excitatory post-synaptic potential
IPSP - Inhibitory post-synaptic potential
EPSP =
depolarization
IPSP =
Hyperpolarization
In directly gated chemical transmission, the effects are _____ and _____
Fast and short-lasting
In the process of directly gated chemical transmission the receptor and the effector are:
the same molecule:
The receptor is located directly on ion channel
Molecule NT binds to receptor
Opens ion channel in receptor
What is the main difference between Indirectly gated and directly gated chemical transmission?
The effector and receptor are the same molecule in directly gated but NOT in indirectly gated
Indirectly gated chemical synaptic transmission involves a ______ (via G-proteins)
Indirectly gated chemical synaptic transmission involves a 2nd messenger System (via G-proteins)
Indirectly chemical synaptic transmission:
Second messenger system uses ____ protiens.
Binding of NT receptor activates ____ which activates _____ which converts ATP into cAMP
Indirectly chemical synaptic transmission:
Second messenger system uses G proteins.
Binding of NT receptor activates GTP which activates Adenylyl cyclase which converts ATP into cAMP
- Instead of simple ion flow = more long-term changes in the cell
Would occur during memory creation/learning etc
**Compare indirectly gated chemical synaptic transmission to Directly Gated Chemical Synaptic Transmission
Directly Gated:
- fast onset
- short lasting
- receptor and ion channel are single protein
Indirectly Gated
- slow onset
- Longer-lasting
- receptor and effector are different molecules
Chemical versus Electrical synapses:
- Electrical synapses are _____
- Great for stereotypical beh but difficult to change
- ALWAYS _____
- Cannot ____ neighbouring cells because of the flow of ions between the cells
- Chemical synapses provide _____
- Only synapse that you can achieve ____
- Different NT have different effects = _____
- _____\_: type, time, strength location
- ________: changes in synaptic ____ and ____
emical versus Electrical synapses:
- Electrical synapses are Inflexible
- Great for stereotypical beh but difficult to change
- ALWAYS excitatory
- Cannot inhibit neighbouring cells because of the flow of ions between the cells
- Chemical synapses provide flexibility
- Only synapse that you can achieve inhibition
- Different NT have different effects = Specificity
- Complexity: type, time, strength location
- Plasticity: changes in synaptic structure and function
If an axon is myelinated, the action potential will travel down it via:
Saltatory electrotonic conduction
What is the sequence of events during synaptic transmission?
(7)
- AP arrives in presynaptic terminal
- Presynaptic terminal depolarizes
- Voltage gated Ca2+ channels open
- Influx of Ca2+ into presynaptic terminal
- Increased Ca2+ causes synaptic vesicles to fuse with presynaptic membrane
- Transmitters released via exocytosis and diffuses across synaptic cleft to bind to and open ligand-gated ion channels
- Ions flow across membrane as dictated by their concentration gradents and depolarizes (EPSP) or hyperpolarizes (IPSP) post-synaptic cell (directly-gated)
Excitatory NT
- channels are:
- Binding = ions flow across membrane results in _______
- binding of ______ to receptor causes sodium ions to flow into the cell = post-synaptic cell more _____ charged = EPSP
Excitatory NT
- channels are: Na+
- Binding = ions flow across membrane results in depolarization of postsynaptic cell
- binding of GLUTAMATE to receptor causes sodium ions to flow into the cell = post-synaptic cell more positively charged generates an: EPSP
Inhibitory NT:
Generates ______ via _______
Inhibitory NT:
Generates IPSP via hyperpolarization
What are the two options for a NT removed from it’s receptor?
Removed and recycled (taken up via endocytosis)
or
degraded (taken up by glia)
What happens when glutamate binds to it’s receptor?
Opens Na+ channels = more positive post-syanptic cell = EPSP
Glutamate is an _______ neurotransmitter
excitatory
EPSPs are ________ (only depolarize a small fraction of what is required to get to threshold)
subthreshold
GABA and Glycine are _______ Neurotransmitters and binding to receptor causes _____ channels to open
GABA and Glycine are Inhibitory Neurotransmitters and binding to receptor causes Cl- channels to open
