Neuron

Glial cells Glial cells surround the soma, axon, and dendrites of neurons and physically and metabolically support neurons. Astrocyte Microglia Oligodendrocyte Myelin Glial cells are the support cells of the nervous system.

突觸前與突觸後神經元放大結構

Resting Membrane Potential (Vr) 靜止膜電位怎麼知？

[Na + ]=150 mM [Na + ]=16 mM [K + ]=5 mM [K + ]=150 mM E Na = 59 mV E k = – 90 mV Concentration gradient Electrical gradient Vm= – 70 mV Na + K+K+

Resting Membrane Potential (V r ) (1) Protein (A – ) (2) Na + -K + ATPase 3Na + out 2K + in (3) K + leak channel K + diffusion >> Na + diffusion

Nernst equation R: ideal gas constant: (J/mole-K) T: absolute temperature: (0 ℃ = o Ｋ ; 37 ℃ = o Ｋ ) z: ion charge F: Faraday’s constant: (coulomb/mole) RT/F=(8.314×2.3×310×1000)/96500=61.33 E = Nernst potential = ion equilibrium potential = reversal potential RT [C] o zF [C] i E= ln 61 [C] o z [C] i E= × log

E Na = 61×log{ [Na + o ]/ [Na + i ] }= 59 mV E k = 61×log{ [K + o ]/ [K + i ] }= – 90 mV E Ca = 30.5×log{ [Ca 2+ o ]/ [Ca 2+ i ] }= 101 mV E Cl = – 61×log{ [Cl – o ]/ [Cl – i ] }= – 73 mV Na + =16 mM K + =150 mM Ca 2+ =1 mM (100 nM) Cl – =8 mM HPO 4 2– = 103 mM HCO 3– =10 mM SO 4 2– =20 mM Na + =150 mM K + =5 mM Ca 2+ =2 mM Cl – =125 mM HPO 4 2– = 2 mM HCO 3– =27 mM SO 4 2– =1 mM E Na = 61×log{ [Na + o ]/ [Na + i ] } = 61× log{ 150/15} = 61× 1 = 61 Intracellular fluid Extracellular fluid 61 [C] o z [C] i E= × log Nernst equation

V=IR I=(1/R)(V) Inward flux=outward flux I K +I Na =(1/R K )(V m -E K )+(1/R Na )(V m -E Na ) =g K (V m -E K )+g Na (V m -E Na ) =0 g K E K +g Na E Na g K +g Na Vm=Vm= 1/R=g (conductance) P (conductance) RT P K [K + ] o +P Na [Na + ] o +P Cl [Cl - ] i F P K [K + ] i +P Na [Na + ] i +P Cl [Cl - ] o = ln Goldman Equation Resting membrane potential (Vm)

Vm=Vm= RT P K [K + ] o +P Na [Na + ] o +P Cl [Cl - ] i F P K [K + ] I +P Na [Na + ] I +P Cl [Cl - ] o ln Goldman Equation RT [K] o zF [K] i E = ln Nernst equation K+ leak channel E Na = 59 mV E k = – 90 mV E Ca = 101 mV E Cl = – 73 mV – 70 mV Na + K+K+ Ca 2+ Cl – Resting membrane potential (Vm) : K + leak channel

Resting Membrane Potential (Vr) 靜止膜電位怎麼知？

(1) Resting state (2) Depolarization (3) Repolarization (4) Hyperpolarization

Mechanisms of neurotransmitter release

Neurotransmitters and Neuromodulatoes

neurotransmitters

Ligand-gated Ion Channels Nicotinic receptor Nicotinic receptor Ionotropic glutamate receptors: Ionotropic glutamate receptors: NMDA NMDA AMPA AMPA Kainate Kainate GABA receptor Glycine Glycine 5HT3 5HT3 P2X (nucleotide receptor) P2X (nucleotide receptor)

1.Ion channels not continuously open 2.Can switch between open and closed state by changing conformation 3.Conformation change regulated by conditions inside and outside cell GABA binding site Lipid bilayer GABA cytosol Na + Gate open Gate closed Ligand-gated channel

Voltage-gated ion channel Na + Channel Na + Channel K + channel K + channel Ca +2 Channel Ca +2 Channel

Figure Diagram of GABA A and GABA B receptors, showing their principal actions. Note that the G protein which mediates the effects of GABA B receptors is a heterodimer. (Reproduced, with permission, from Bowery NG, Brown DA: The cloning of GABA B receptors. Nature 1997;386:223. Copyright © 1997 by Macmillan Magazines Ltd.) GABA receptors

Cell patch clamp

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