Exam1Lec5NeuromuscularJunctionandPostSynapticSignaling Flashcards
What is post-synaptic signaling (synpatic transmission)?
Interpreting the transmitted signal and translation of the signal into a change in post-synaptic Vm.
What triggers skeletal muscle contraction and respiratory muscle control (involuntary + voluntary)
NMJ
What are the classes of membrane receptors?
- Ionotropic (ligand-gated): fast response
- Metabrotropic (GPCR): slow and variable response
Direct activation of ionotropic (ligand-gated) receptors channels elicits ___
fast PSPs
What are 5 examples of ionotropic (ligand-gated) receptors?
- Nicotinic acetycholine receptor (nAChR)-Acetycholine
- NMDA & AMPA receptors-Glutamate
- Serotonin receptor channel -5HT3 (excitatory)
- GABA receptors (Types A and C)
- Glycine receptor (GlyR)
5-HT1 AND 5-HT5 are serotonon receptors associated with inhibitory effects
What are 5 examples of ionotropic (ligand-gated) receptors?
- Nicotinic acetycholine receptor (nAChR)-Acetycholine
- NMDA & AMPA receptors-Glutamate
- Serotonin receptor channel -5HT3 (excitatory)
- GABA receptors (Types A and C)
- Glycome receptor (GlyR)
5-HT1 AND 5-HT5 are serotonon receptors associated with inhibitory effects
Activation of metabotropic (GPCRs) elicits____
Slow PSPs
What are 4 examples of metabotropic (GPCRs) receptors?
- Muscarininc acetylcholime receptor (mAChR)
- Metabotropic Glutamate receptor (mGluR)
- Biogenic Amine receptors (serotonin (not 5HTR), dopamine, NE, histamine)
- GABA receptor (Type B)
Metabotropic Glutamate receptor
neurotransmitter?
Receptor?
G-protein?
Cascade?
Final effect?
- Glutamate
- Binds to mGluR receptor
- Gq glycoprotein
- Gq activates phospholipase C which results in formation of IP3 which activates Ca2+ release. Activated phospholipase C can also result in formation of diaglycerol which then activates PKC.
- incr protein phosphorylation, and activate calcium-binding proteins
Biogenic Amine receptor-Norepinephrine
neurotransmitter?
Receptor?
G-protein?
Cascade?
Final effect?
- Norepinephrine
- binds to Beta-adrenergic receptor
- Gs
- Gs activates adenycl cylase which incr cAMP, this then incr activity of PKA
- Incr protein phosphorylation
Biogenic Amine receptor-Dopamine
neurotransmitter?
Receptor?
G-protein?
Cascade?
Final effect?
- Dopamine
- binds to Dopamine D2
- Gi
- Gi inhibits adenycl cyclase resulting in decr cAMP which decr activity of PKA.
- Decrs protein phosphorylation
What are the sources of Ca2+ (what incr Ca2+)?
Plasma membrane:
* Voltage-gates Ca2+ channels
* Various ligans-gated channels
Endoplasmic reticulum:
* IP3 receptos
* RYR
What are the removal mechanisms of Ca2+ (what decr Ca2+)?
Plasma membrane:
* Na+/Ca2+ exchanger
* Ca2+ pump
Endoplasmic reticulum:
* Ca2+ pump
Mitochondria
Following neurotransmitter activation, the postsynaptic membrane potential (Vm) will always move toward the ____ of the activated neurotransmitter indiced conductance.
reversal potential
What is EPSP?
Postsynaptic potentials that INCR probability of causing the postsynaptic cell to fire an action potential
What is IPSP?
Postsynaptic potentials that DECR the probability of causing the postsynaptic cell to fire an action potential
For epsp, the reversal potential of induced conductance is more positive or more negative than threshold?
More positve
Erev>Threshold
For ipsp is the reversal potential of induced conductance more positve or more negative than threshold?
more negative
Erev<Threshold
We can fire an IPSP and still depolarize. How?
Erev is below threshold, but v rest is more negative than erev and it is trying to become more positive to reach erev, so it depolarizes, but does NOT reach threshold to fire an ap (because more neg than threshold)
What is the effect of incr postynaptic conductance of Na+?
EPSP
What is the effect of incr postynaptic conductance of K+?
IPSP
What is the effect of incr postynaptic conductance of Ca+?
EPSP
What is the effect of incr postynaptic conductance of Cl-?
IPSP
What is the effect of incr postynaptic conductance of Na+/K+ equally?
EPSP
What is the effect of decr conductance of K+ ?
decr activatino of K+ channels
EPSP
k+ stays w/in cell and doesnt move out, more pos charge
What is convergence of input?
Several neurons synapse onto a single neuron
What is divergence of output?
A single neuron projects onto several neurons
Temporal and spatial summation of ____ determines the excitability of the post synaptic cell.
all EPSPs and IPSPs
1 EPSP is not enough to reach threshold and fire ap, while summed epsp is enough.
What are afferent neurons?
Carry info from sensory receptors to the CNS
What are efferent neurons?
Carry motor info away from the CNS to the muscles and glands of the body.
Explain the patella/stretch reflex
- Muscle sensory receptors detect stretch caused by hammer tap
- Type Ia/II a AFFERENT fibers are activated and signls to CNS.
- alpha motor neurons (EFFERENT) activates extensors/qudricep
- INTERNEURON mediates inhibition of motor axons (efferent) to flexors/hamstrings
- Leg extends