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Resting Potential

February 26, 2014 Synaptic Transmission

Yikes! Midterm paper due Thursday, March 27

At Nernst Potential

K+ experiment

Why does the line deviate from the K theoretical values at lower [K]?

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Squid giant axon- a model prep Squid giant axon- RP experiment

Squid giant axon- membrane prep

40,000 APs can fire!

Squid giant axon- experimental chamber

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Results- K: RP relationship

“normal”

At Rest: RP in neurons is never as negative as Keq. Why? INa = IK? At Rest: gK 50X > gNA

At Rest: INa = IK? V=IR

IK = gK (Vm-EK) INa = gNa (Vm-ENa) gK (Vm-EK) = gNa (Vm-ENa)

Other contributions to RP?

Membrane Model at Rest

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Changes in “ RP” by changing ionic conductances- movie

Synaptic Transmission Refresher

axon!

Synaptic input Synaptic transmission 1) signal transmission between NS components and effectors 2) A site of plasticity for learning and memory 3) A site of action for disease, psychoactive drugs

Types of Chemical Synaptic Transmission?

direct, fast iontropic

indirect, ~slow metabotropic

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Stimulate presynaptic axon

Ionotropic Transmission

Synapse tutorial AP/PSP, page 7 See Synapse Tutorial on class web site for review

Steps in ionotropic chemical synaptic transmission