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Purpose:Chlorideeffluxplaysanimportantroleinaqueoushumorproduction .Chloridecurrentshavebeendescribedin bovinenon_pigmentedciliaryepithelium(NPE) ,intransformedculturedhumanNPE ,andinbovinevolume_activatedchloridechannels describedinthelatter.ItisthebasolateralmembranesoftheNPEofocularciliaryprocessesthatcomprisetheexitpathwayforthe processofaqueoussecretionperformedbythedoublesyncytiallayerofciliaryepithelium ,however .Therefore,westudiedbothcell_at tached ,and ,excised ,inside_outpatchesfrombasolateralmembranesoftheNPE .Methods :Cell_attachedandcell_freeexcisedpatches wereformedfromthebasolateralmembranesofNPEandsinglechannelcurrentsrecordedwithaDagan 390 0Apatchclampamplifier . Results:Alowconductancechannelof 14pSwasobservedandrecordedin 30 %ofcellattachedpatchesandin 35 %ofexcisedinside outpatchesundersymmetricalconditions (16 0mMchloride) .Thischanneldisplayedanearlylinearcurrent_voltagerelationship ,with anopenprobabilitythatwasnotvoltage_dependent.Thechannelwaschloride_selective :N_methyl_D_glucamine(NMDG)usedas cationdidnotalterthecurrentprofilenorthereversalprotein .Further,withinside_outpatches,thereversalpotentialwasclosetozero (0 .3+ / - 0 .5mV(10 )insymmetrical(16 0mV)chloride,butshiftedto - 32 .3+ / - 0 .5mV(5 )whentheconcentrationofchlo rideinthebathingsolutionwasreducedto 40mMwhiletherecordingpipettewasheldat 16 0mM .Thisvalueapproachesthetheo reticalequilibriumpotentialofchloridefortheseconditions.Thechannelanionpermeabilitysequencewas :I->NO-3 >or =Br->Cl- >gluconate_approximatelyequaltoaspartate_ .Threedifferentchloride_channelblockersinhibitedthechannelactivity .Conclusion :A lowconductancechannel,selectiveforchloride,and ,modulatedbybetaadrenergicandVIPstimulation ,basedonitsensitivitytoex ogenouslyaddedcAMP ,ATPandthecatalyticsubunitofPKA ,ispresentintheexitbasolateralmembranesofrabbitNPEandcon tributestotheprocessofaqueoushumorformation .
Purpose: Chlorideeffluxplaysanimportantroleinaqueoushumorproduction .Chloridecurrentshavebeendescribedin bovinenon_pigmentedciliaryepithelium (NPE), intransformedculturedhumanNPE, andinbovinevolume_activatedchloridechannels describedinthelatter.ItisthebasolateralmembranesoftheNPEofocularciliaryprocessesthatcomprisetheexitpathwayforthe processofaqueoussecretionperformedbythedoublesyncytiallayerofciliaryepithelium, however .Therefore, westudiedbothcell_at tached, and, excised, inside_outpatchesfrombasolateralmembranesoftheNPE .Methods: Cell_attachedandcell_freeexcisedpatches wereformedfromthebasolateralmembranesofNPEandsinglechannelcurrentsrecordedwithaDagan 390 0Apatchclampamplifier Results:. Alowconductancechannelof 14pSwasobservedandrecordedin 30% ofcellattachedpatchesandin 35% ofexcisedinside outpatchesundersymmetricalconditions ( 16 0 mM Chloride). Hischanneldisplayedanearlylinearcurrent_voltagerelationship, with anopenprobabilitythatwasnotvoltage_dependent.Thechannelwaschloride _selective: N_methyl_D_glucamine (NMDG) usedas cation d current total current current fluorine receptor protein. Further, withinside_outpatches, thereversalpotentialwasclosetozero (0 .3+ / - 0 .5mV (10) insymmetrical (16 0mV) chloride, butshiftedto - 32 .3+ / - 0 .5mV (5) whentheconcentrationofchlo rideinthebathingsolutionwasreducedto 40mMwhiletherecordingpipettewasheldat 16 0mM .Thisvalueapproachesthetheo reticalequilibriumpotentialofchloridefortheseconditions.Thechannelanionpermeabilitysequencewas: I-> NO-3> or = Br-> Cl-> gluconate_approximatelyequaltoaspartate_ .Threedifferentchloride_channelblockersinhibitedthechannelactivity .Conclusion: A lowconductancechannel, selectiveforchloride, and, modulatedbybetaadrenergicandVIPstimulation, basedonitsensitivitytoex ogenouslyaddedcAMP, ATPandthecatalyticsubunitofPKA, ispresentintheexitbasolateralmembranesofrabbitNPEandcon tributestotheprocessofaqueoushumorformation.