北大神经生物学课件3-1离子通道和神经元的电活动.pdf

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1、NeuronalElectricActivities神经元的电活动主讲教师刘风雨万有神经科学研究所、神经生物学系NeuronalElectricActivitiesInclude:•RestPotential(Chapter3)•ActionPotential(Chapter4)•LocalPotentials–Post-SynapticPotential•ExcitatoryPost-SynapticPotential•InhibitoryPost-SynapticPotential–End-platePotential–Rece

2、ptorPotentialChapter3TheNeuronalMembraneatRest•TheCASTOFCHEMICALS–CytosolandExtracellularFluid–ThePhospholipidMembrane–Protein•TheMOVEMENTOFIONS–Diffusion–Electricity•TheIONICBASISOFRESTINGMEMBRANEPOTENTIAL–EquilibriumPotential–TheDistributionofIonsAcrosstheMembrane–Re

3、lativeIonPermeabilitiesofMembraneatRest–TheImportanceofRegulatingtheExternalPotassiumConcentration•CONCLUDINGREMARKSCytosolandExtracellularFluid•Water:–Itsunevendistributionofelectricalcharge,soHOisapolarmolecule2•Ions:–Saltdissolvesreadilyinwaterbecausethechargedporti

4、onsofthewatermoleculehaveastrongerattractionfortheionsthantheyhaveforeachotherThePhospholipidMembrane(磷脂膜)Thelipidsoftheneuronalmembraneforming:òabarriertowater-solubleionsòabarriertowater头端-极性磷酸盐-亲水尾端-非极性碳氢化合物-疏水5Protein•Theseproteinsprovideroutesforionstocrosstheneur

5、onalmembrane.•Therestingandactionpotentialsdependonspecialproteinsthatspanthephospholipidbilayer.Protein–AminoAcidsThePeptideBond(肽键)andaPolypeptide(多肽)Figure3.6ProteinStructureThetertiarystructureTheprimarystructureThesecondarystructureThequaternarystructureEachofthed

6、ifferentpolypeptidescontributingtoaproteinwithquaternarystructureiscalledasubunit(亚基).ChannelProteins•ChannelproteinisFigure3.7AMembranesuspendedinaIonChannelphospholipidbilayer,withits–hydrophobic(疏水的)portioninsidethemembrane–hydrophilic(亲水的)endsexposedtothewateryenvi

7、ronmentsoneitherside10TwoPropertiesofIonChannels•Ionselectivity(离子选择性)–Thediameterofthepore–ThenatureoftheRgroupsliningit•Gating(门控特性)–Channelswiththispropertycanbeopenedandclosed-gatedbychangesinthelocalmicroenvironmentofthemembraneIonPumps(离子泵)•Ionpumpsareenzymesthat

8、usetheenergyreleasedbythebreakdownofATPtotransportcertainionsacrossthemembraneChapter3TheNeuronalMembraneatRest•THECA