Sensor potential

Introduction

Ifthenervefiberproducesanimpulsetowardthecenterduetothispotentialchange,itisspecificallycalledageneratorpotential.

Researcher'sexplanation

Accordingtosomeresearchers,thereceptorpotentialreferstothemassresponseofthesensorycellpopulation,suchastheERGproducedbylightirradiatingtheretina.Microphonepotentialsseeninthecochleawhensoundisstimulated,whilegeneratorpotentialsrefertonon-conductive,gradual(analog)potentialsrecordedbyasinglesensorcell.Onthecontrary,someresearchersregardtheelectricalresponseofsensorcellgroupssuchasERGandmicrophonepotentialasgeneratorpotential,andthepotentialgeneratedbyasinglesensorcellassensorpotential.Duetothedevelopmentofthemicroelectrodemethod,potentialchangeshavenowbeenrecordedinalmostallreceptors.Eventhoughtheenergyconversionmechanismisdifferentinvariousreceptors,asanelectricalphenomenon,itappearsaspartialdepolarizationofthemembraneinalmostallcasesofinvertebratesorvertebrates(onlyconecellsofthevertebrateomentum),Hyperpolarizationduetolightstimulationisanexception).Duringdepolarization,mostoftherelevantionsareNa+,whichisgenerallybelievedtobeduetotheincreasedionpermeabilityofthesensorcellmembrane,butnotnecessarilytheincreasedpermeabilityofthechemoreceptor,butmaybetheadsorptionofthesubstanceonthemembrane.Playsamajorrole.Inprimarysensorycells,thesensorpotentialdirectlygeneratesconductivedischarges(generatorpotentials)atthelowestfiringthresholdofnervefibers,whileinsecondarysensorycells,nervefiringistriggeredviasynapsesbetweensensorcellsandnerveendings.Suchsynapsesarenowconsideredtobealmostallchemicalsynapses,buttherearemanyunclearabouttransmitters.Ontheomentum,theelectricpotentialchangescausedbylightirradiationarerecordedbyHolmgren(1865);inthecochlea,theelectricpotentialchangestosoundstimulationarethefirstbyE.G.WeverandBray(C.W.Brey.1930),andKatz(B.Katz,1950)recordedthepotentialchangescausedbystretchingfromthemusclespindle.Sincethen,ithasbeenrecordedfromvariousreceptorcellswiththehelpofmicroelectrodes.Theenergyconversionmechanismthatcausesthispotentialchangeiscurrentlybeingstudied.