Defining a Channel - Neuron · Defining a Channel voltage and ligand gated leave out pumps ionic...
Transcript of Defining a Channel - Neuron · Defining a Channel voltage and ligand gated leave out pumps ionic...
Defining a Channelvoltage and ligand gated
leave out pumps ionic accumulation
Classical HH−like Kinetic scheme
ohmic conductance GHK constant field
multiple gates
transition style (α, β) 8( , τ)
fractional openness independent identical subunits
ion selective
voltage sensitiveligand sensitivefunctions tables
−50 0 50 100 150
−20
−10
0
10
i = p * ghk(v, ci, co, z)
v
i
i = g * (v − e)
10 100 1
Ohmic vs Constant Field
−40 −20 0 20 40 600
1
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A*exp(k/2*(v−d))
A*k*(v−d)/(1 − exp(−k*(v−d)))
2*A/(1 + exp(−k*(v−d)))
1/ms
mV
ExponentialEinsteinBoltzmann
functions.
generally have the form ofVoltage sensitive and rates α β
EE*
0E1
2
e EkT+1
1E−P ~ e kT
=2
2
2
If the energy difference betweenstates is linear with voltage, thenthe steady state is a Boltzmanndistribution.
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Propertiesleak Density MechanismNonSpecific ohmic ion current i_leak (mA/cm2) = g_leak * (v - e_leak)g = gmax Default gmax = 0 (S/cm2) e = 0 (mV)
Select here to construct gates
ChannelBuild[0] managed KSChan[0]
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somapashhleak
SingleCompartment
single compartmentCell BuilderNetWork CellNetWork BuilderLinear CircuitChannel Builder Density
Pointimport KSChan
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Propertiesleak Density MechanismNonSpecific ohmic ion current i_leak (mA/cm2) = g_leak * (v - e_leak)g = gmax Default gmax = 0 (S/cm2) e = 0 (mV)
Select here to construct gates
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Propertiesnahh Density Mechanismna ohmic ion current ina (mA/cm2) = g_nahh * (v - ena)g = gmax * m^3 * h Default gmax = 0 (S/cm2)
m’ = am*(1 - m) - bm*mh’ = ah*(1 - h) - bh*h
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Channel NameSelective for Ion...
Ohmic i=g*(v-e)Goldman-Hodgkin-Katz
Default gmax (or pmax) HH sodium channel HH potassium channelClone channel typeCopy gates fromText to stdout
Provide transition aliasesUse fixed step HH rate tables
Gate Constructor
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Propertiesnahh Density Mechanismna ohmic ion current ina = g_nahh * (v - ena)g = gmax * m^3 * h Default gmax = 0 (S/cm2)
m’ = am*(1 - m) - bm*mh’ = ah*(1 - h) - bh*h
ChannelBuild[0] managed KSChan[0]
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Select hh state or ks transition to change propertiesm
h
m^3m’ = am*(1 - m) - bm*m
Power 3Fractional Conductancem fraction 1
Adjust Run
-90 -40 10 600
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1infmtaum
m <-> m (a, b) (KSTrans[0])Display inf, tau
am = A*x/(1 - exp(-x)) where x = k*(v - d)A 1
k 0.1
d -40
bm = A*exp(k*(v - d)))
ChannelBuildGateGUI[0] for ChannelBuild[0]
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Propertiesnahh Density Mechanismna ohmic ion current ina (mA/cm2) = g_nahh * (v - ena)g = gmax * m^3 * h Default gmax = 0 (S/cm2)
m’ = am*(1 - m) - bm*mh’ = ah*(1 - h) - bh*h
ChannelBuild[0] managed KSChan[0]
Close HideStates Transitions Properties
Select hh state or ks transition to change propertiesm
h
hh’ = ah*(1 - h) - bh*h
Power 1Fractional Conductanceh fraction 1
Adjust Run
-90 -40 10 600
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1ahbh
h <-> h (a, b) (KSTrans[1])Display inf, tau
ah = A*exp(k*(v - d)))A (/ms) 0.07
k (/mV) -0.05
d (mV) -65
bh = A/(1 + exp(-k*(d - v)))A (/ms) 1
k (/mV) -0.1
d (mV) -35
EquationType
ChannelBuildGateGUI[0] for ChannelBuild[0]
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alpha,betaahbh
a,binf,tauCopy
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Propertiesnahh Density Mechanismna ohmic ion current ina (mA/cm2) = g_nahh * (v - ena)g = gmax * m^3 * h Default gmax = 0 (S/cm2)
m’ = am*(1 - m) - bm*mh’ = ah*(1 - h) - bh*h
ChannelBuild[0] managed KSChan[0]
Close HideStates Transitions Properties
Select hh state or ks transition to change propertiesm
h
hh’ = ah*(1 - h) - bh*h
Power 1Fractional Conductanceh fraction 1
Adjust Run
-90 -40 10 600
0.2
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-90 -40 10 600
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1ahbh
h <-> h (a, b) (KSTrans[1])Display inf, tau
ah = A*exp(k*(v - d)))A (/ms) 0.07
k (/mV) -0.05
d (mV) -65
bh = A/(1 + exp(-k*(d - v)))A (/ms) 1
k (/mV) -0.1
d (mV) -35
EquationType
ChannelBuildGateGUI[0] for ChannelBuild[0]
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alpha,betaahbh
AA*exp(k*(v - d)))A*x/(1 - exp(-x)) where x = k*(v - d)A/(1 + exp(-k*(d - v)))KSChanTable
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Propertiesnahh Density Mechanismna ohmic ion current ina (mA/cm2) = g_nahh * (v - ena)g = gmax * m^3 * h Default gmax = 0 (S/cm2)
m’ = am*(1 - m) - bm*mh’ = (hinf - h)/htau
ChannelBuild[0] managed KSChan[0]
Close HideStates Transitions Properties
Select hh state or ks transition to change propertiesm
h
hh’ = (hinf - h)/htau
Power 1Fractional Conductanceh fraction 1
Adjust Run
-90 -40 10 600
0.2
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1infhtauh
h <-> h (inf, tau) (KSTrans[1])Display inf, tau
infh = KSChanBGinfK (/ms) 1
vhalf (mV) -20
z 4
gam 0.5
tau0 (ms) 0.1
tauh = KSChanBGtau
EquationType
ChannelBuildGateGUI[0] for ChannelBuild[0]
inf,tauinfhtauh
AA/(1 + exp(-k*(d - v)))KSChanBGinfKSChanTable
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Propertiesleak Density MechanismNonSpecific ohmic ion current i_leak (mA/cm2) = g_leak * (v - e_leak)g = gmax * 0 * 0 * O Default gmax = 0 (S/cm2) e = 0 (mV)
C’ = aC*(1 - C) - bC*CC2’ = aC2*(1 - C2) - bC2*C2O’ = aO*(1 - O) - bO*O
ChannelBuild[0] managed KSChan[0]
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Drag new state from left. Drag off canvas to deleteOC
C C2
O
no gate selected
Adjust Run
-90 -40 10 600
0.20.40.60.8
1
-90 -40 10 600
0.20.40.60.8
1no KSTrans selected
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Propertieskca Density Mechanismk ohmic ion current ik (mA/cm2) = g_kca * (v - ek)g = gmax * 0 * O Default gmax = 0 (S/cm2)
0: 2 state, 1 transitionsO’ = aO*(1 - O) - bO*O
ChannelBuild[0] managed KSChan[0]
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New transition pair: select source and drag to target
C C2v
O
no gate selected
Adjust Run
-90 -40 10 600
0.20.40.60.8
1
-90 -40 10 600
0.20.40.60.8
1no KSTrans selected
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Propertiesleak Density MechanismNonSpecific ohmic ion current i_leak (mA/cm2) = g_leak * (v - e_leak)g = gmax * O Default gmax = 0 (S/cm2) e = 0 (mV)
O: 3 state, 2 transitions
ChannelBuild[0] managed KSChan[0]
Close HideStates Transitions Properties
Select hh state or ks transition to change properties
C C2 Ov v
OO: 3 state, 2 transitions
Power 1Fractional ConductanceC2 fraction 0
O fraction 1
Adjust Run
-90 -40 10 600
0.20.40.60.8
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0.20.40.60.8
1 aC2ObC2O
bC2O = AA (/ms) 0
EquationType
ChannelBuildGateGUI[0] for ChannelBuild[0]
alpha,betaaC2ObC2O
a,binf,tauLigandCopy
nainaokikocaicaoNew Ligand
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Select hh state or ks transition to change properties
C C2 Ov cai
OO: 3 state, 2 transitions
Power 1Fractional ConductanceC2 fraction 0
O fraction 1
Adjust Run
-90 -40 10 600
0.20.40.60.8
1
-90 -40 10 600
0.20.40.60.8
1 aC2ObC2O
C2 + cai <-> O (a, b) (KSTrans[9])Display inf, tau
aC2O = A
ChannelBuildGateGUI[0] for ChannelBuild[0]
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Propertieskca Density Mechanismk ohmic ion current ik (mA/cm2) = g_kca * (v - ek)g = gmax * O Default gmax = 0 (S/cm2)
O: 3 state, 2 transitions
ChannelBuild[0] managed KSChan[0]
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Close HideStates Transitions Properties
Select hh state or ks transition to change properties
C C2 Ov cai
C3 O2v
O3
(0.25*C2 + O)(0.25*C2 + O): 3 state, 2 transitions
Power 1Fractional ConductanceC2 fraction 0.25
O fraction 1
Adjust Run
-90 -40 10 600
0.20.40.60.8
1
-90 -40 10 600
0.20.40.60.8
1 aC2ObC2O
C2 + cai <-> O (a, b) (KSTrans[29])Display inf, tau
aC2O = A
ChannelBuildGateGUI[0] for ChannelBuild[0]
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Propertieskca Density Mechanismk ohmic ion current ik (mA/cm2) = g_kca * (v - ek)g = gmax * (0.25*C2 + O) * O2 * O3 Default gmax = 0 (S/cm2)
(0.25*C2 + O): 3 state, 2 transitionsO2: 2 state, 1 transitionsO3’ = aO3*(1 - O3) - bO3*O3
ChannelBuild[0] managed KSChan[0]
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Propertiesnahh Density Mechanismna ohmic ion current ina (mA/cm2) = g_nahh * (v - ena)g = gmax * m3h1 Default gmax = 0.12 (S/cm2)
m3h1: 8 state, 10 transitions
ChannelBuild[0] managed KSChan[0]
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Propertieskhh Density Mechanismk ohmic ion current ik (mA/cm2) = g_khh * (v - ek)g = gmax * n4 Default gmax = 0.036 (S/cm2)
n4: 5 state, 4 transitions
ChannelBuild[1] managed KSChan[1]
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Propertiesleak Density MechanismNonSpecific ohmic ion current i_leak (mA/cm2) = g_leak * (v - e_leak)g = gmax Default gmax = 0.0003 (S/cm2) e = -54.3 (mV)
ChannelBuild[2] managed KSChan[2]
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Propertiesnahh0 Point Process (Allow Single Channels)na ohmic ion current ina (mA/cm2) = nahh0.g * (v - ena)*(0.01/area)g = gmax * m3h1 Default gmax = 0.12 (uS)
m3h1: 8 state, 10 transitions
ChannelBuild[3] managed KSChan[3]
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somapashhnahhkhhleak
SingleCompartment
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SelectPointProcessShow
IClamp[0]at: soma(0.5)
IClamp[0]del (ms) 0.5
dur (ms) 0.1
amp (nA) 0.3
i (nA) 0
PointProcessManagerClose Hide
0 1 2 3 4 50
0.1
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0.3
0 1 2 3 4 50
0.1
0.2
0.3 nahh0[0].m3h1
Graph Move Text x -0.5 : 5.5 y -0.03 : 0.33
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SelectPointProcessShow
nahh0[0]at: soma(0.5)
nahh0[0]Nsingle 0
gmax (uS) 0.12
g (uS) 6.816e-08
PointProcessManager
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0 1 2 3 4 5
-80
-40
0
40
0 1 2 3 4 5
-80
-40
0
40v(.5)
Graph[0] x -0.5 : 5.5 y -92 : 52
Close HideStates Transitions Properties
Select hh state or ks transition to change properties
m0h0 m1h0 m2h0 m3h0
m0h1 m1h1 m2h1 m3h1
v v v
v v vv v v v
m3h1m3h1: 8 state, 10 transitions
Power 1Fractional Conductancem0h0 fraction 0
m1h0 fraction 0
Adjust Run
-90 -40 10 600
0.20.40.60.8
1
-90 -40 10 600
0.20.40.60.8
1 infm0h0m1h0taum0h0m1h0
m0h0 <-> m1h0 (a, b) (KSTrans[14])Display inf, tau
am0h0m1h0 = A*x/(1 - exp(-x)) where x = k*(v - d)
ChannelBuildGateGUI[0] for ChannelBuild[3]
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Init (mV) -65
Init & Run
Stop
Continue til (ms) 5
Continue for (ms) 1
Single Step
t (ms) 5
Tstop (ms) 5
dt (ms) 0.025
Points plotted/ms 40Quiet
Real Time (s) 0.01
RunControl
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4 567
8 9
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Print & File Window Manager
nahh0[0]at: soma(0.5)
nahh0[0]Nsingle 0
gmax (uS) 0.12
g (uS) 6.816e-08
i (nA) -8.5813e-06
PointProcessManager
0 1 2 3 4 5
-80
-40
0
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0 1 2 3 4 5
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-40
0
40v(.5)
Graph[0] x -0.5 : 5.5 y -92 : 52
0 1 2 3 4 50
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0 1 2 3 4 50
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0.3 nahh0[0].m3h1
Graph[1] x -0.5 : 5.5 y -0.03 : 0.33
nahh0[0]at: soma(0.5)
nahh0[0]Nsingle 1000
gmax (uS) 0.00012
g (uS) 0
i (nA) -0
PointProcessManager
0 1 2 3 4 5
-80
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0
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0 1 2 3 4 5
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0
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Graph[0] Color/Brush x -0.5 : 5.5 y -92 : 52
0 1 2 3 4 50
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Graph[1] Color/Brush x -0.5 : 5.5 y -30 : 330
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0 1 2 3 4 50
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300nahh0[0].m3h1
20935 points
1.2 1.3 1.4 1.5250
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1.2 1.3 1.4 1.5250
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290nahh0[0].m3h1
1.32 1.325 1.33 1.335 1.34262
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1.32 1.325 1.33 1.335 1.34262
264
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268nahh0[0].m3h1
Use variable dtAbsolute Tolerance 0.001
Atol Scale Tool Details