Lecture 5 (Revised) Flashcards
Synaptic Transmission?
Translation of signal into a change in postsynaptic Vm
(Synaptic Transmission)
Classes of Membrane Receptors?
1) Ionotropic (Ligand-Gated)
-Fast response
2) Metabotropic (GPCR)
-Slow and variable response
Ionotropic (Ligand-Gated) Receptors?
-Direct activation of neurotransmitter receptor channel elicits fast PSPs
-Examples:
1) nAChR - Acetylcholine
2) NMDA and AMPA Receptors - Glutamate
3) Serotonin Receptor Channel - 5HT3 (Excitatory)
4) GABA Receptors (Types A and C)
5) Glycine Receptor (GlyR)
Metabotropic (G-Protein Coupled) Receptors?
-Activation of G-Protein coupled receptor elicits slow PSPs
-Examples:
1) mAChR
2) mGluR
3) Biogenic Amine Receptors (Serotonin (excluding 5HT3R)) (Dopamine, NE, Histamine)
4) GABA Receptor (Type B)
Metabotropic Receptors + 2nd Messenger Pathways?
-Gg activates phospholipase C which results in formation of:
(IP3 –> Increased [Ca2+])
(Diacylglycerol –> activation of PKC)
-Gs activates adenyl cyclase resulting in:
(Increased cAMP –> Increased activity of PKA)
-Gi inhibits adenyl cyclase resulting in:
(Decreased cAMP –> Decreased acuity of PKA)
(Metabotropic Receptors + 2nd Messenger Pathways)
Gg?
Gg activates phospholipase C which results in formation of:
(IP3 –> Increased [Ca2+])
(Diacylglycerol –> activation of PKC)
(Metabotropic Receptors + 2nd Messenger Pathways)
Gs?
Gs activates adenyl cyclase resulting in:
(Increased cAMP –> Increased activity of PKA)
(Metabotropic Receptors + 2nd Messenger Pathways)
Gi?
Gi inhibits adenyl cyclase resulting in:
(Decreased cAMP –> Decreased acuity of PKA)
Following neurotransmitter receptor activation, postsynaptic membrane potential (Vm) will always move?
Toward reversal potential of activated neurotransmitter receptor induced conductance
1) EPSP
2) IPSP
EPSP postsynaptic potentials that?
Increase probability of causing postsynaptic cell to fire an AP
IPSP postsynaptic potentials that?
Decrease probability of causing postsynaptic cell to fire an AP
Reversal Potential?
Point at which direction of net current flow reverses and is same as equilibrium potential (almost identical to equilibrium potential)
EPSP reversal potential of induced conductance is?
More positive than threshold (will meet threshold so get AP)
IPSP reversal potential of induced conductance is?
More negative than threshold (will fire an IPSP) (Hyperpolarization)
(Increasing postsynaptic conductance)
Na+?
EPSP
(Increasing postsynaptic conductance)
K+?
IPSP
(Increasing postsynaptic conductance)
Ca+?
EPSP
(Increasing postsynaptic conductance)
Cl-?
IPSP
(Increasing postsynaptic conductance)
Na+/K+ equally?
EPSP
(Increasing postsynaptic conductance)
Decreasing conductance of K+ produces?
EPSP
Convergence of input?
Several neurons synapse onto a single neuron
Convergence of output?
Single neuron projects onto several neurons
Grand Postsynaptic Potential?
Temporal and spatial summation of all EPSP’s and IPSP’s determines excitability of postsynaptic cell
Afferent neurons carry?
Information from sensory receptors to CNS
