Neurons IonicConductances Records

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Record
  ID Neurons
  ID Methods Electrophysiology
  Conductance name
  Charge carrier
  Peak conductance
  V threshold
  V half activation
  V peak
  Citations
  Reference figures
  Reference text
  Comments
Methods Electrophysiology.ID Ref.
Neurons.ID Ref.
-2090324328 -2090324328 -135019817 BK K+ 0.134+-0.008 channels/µm^2 - - - "Patches were excised at a mean distance of 18+-2.6 µm from the soma-apical
dendritic junction."p.191 		Table 2 p.191 - -135019817 -2090324328
-1208544038 -1208544038 -1135746851 BK K+ - - - - "With ChTX in the pipette solution (1 µM), BK channels of inside-out patches
were also inhibited (Fig. 10B; n = 5). Pipette tips were filled with the
standard intra-cellular solution and backfilled with ChTX-containing solution,
so that channel openings were present initially, and then blocked as ChTX
diffused from the shank into the electrode tip."p.194

"Perfusion of 0.5 mM TEA-containing solution inhibited BK channel openings in
outside-out patches in both P14 (n = 4) and P1 (n = 2) neurons (Fig. 10C). The
effects of TEA appeared as a reduction in unitary current amplitude,
presumably because TEA blocks and unblocks the channel with very fast kinetics
not resolvable by the recording system (Benham et al. 1985); Reinhart et al.
1989; Yellen 1984)."p.194

"When perfused over inside-out patches, trifluoperazine (50 µM), a
phenothiazine derivative, also blocked BK channel activities in both P14 (n =
3) and P1 (n = 2) neurons (Fig. 10D) in a pattern similar to that reported by
Ikemoto et al. (1992)."p.194 		Fig.10 p.194 - -1135746851 -1208544038
-1208544038 -1208544038 -135019817 BK K+ 181.6+-3.9 pS (single channel) ~ -80 mV -12.7+-1.8 mV - "Rectification of BK channels was observed in recordings of responses to ramp
voltage commands (Fig. 2, A and B) as previously reported (Kang et al. 1994).
In a minority of somatic patches (n = 14, 8.1%), we also found a 30-pS Kca
channel."p.190

"According to the Goldman-Hodgkin-Katz relationship, the calculated ratio of
K+ to Na+ permeability was greater than 15:1."p.190

"However, in P28 neurons there was no correlation between channel number and
patch area (r^2 << 0.01), and each patch contained about four, indicating
apparent clustering."p.191 		Figs.2,4,5,6,7,8,9. Table 3 p.190-193. Also Ca2+ dependent (see figs above). Parameters fitted to Boltzmann equation
(Open probabilities). Voltage and Ca-conc. dependencies. 		-135019817 -1208544038
-1208544038 -1208544038 976026094 BK K+ - - - - "When perfused over five outside-out patches, 30 and 100 nM only partially
inhibited, and 1 µM ChTX completely blocked BK channel openings en the same
patches (Fig. 10A). Thirty and 100 nM ChTX reduced P(0) of BK channels to
82.5+-3.1% and 51.6+-3.2% of control values (n = 5), respectively."p.194 		Fig.10 p.194 - 976026094 -1208544038
-945125805 -945125805 -135019817 BK K+ 0.312+-0.008 channels/µm^2 - - - - Table 2 p.191 - -135019817 -945125805
-625879160 -625879160 1006622979 I(A) K+ 8.5 +- 0.3 pS - -24.5 +- 3.7 mV - "Two distinct types of single-channel were observed in cell-attached and
outside-out somatic patches (Figs 2 and 3). One type of channel had shorter
open times and a mean conductance of 8.5 +- 0.3 pS (+- S.E.M., n=3; Fig. 2).
Averages of this channel type gave a pure I(A)-like current (Fig. 2A)." p.613

"For convenience, the fast transient and slowly inactivating/non-inactivating
currents seen in these patches will henceforth be called I(A) and I(K),
respectively."p.614 		Fig. 2 pp.613-614 More parameters on activation/inactivation and timeconstants given. 1006622979 -625879160
-625879160 -625879160 1006622979 I(K) K+ 20.3 +- 1.2 pS - -7.6 +- 1.5 mV - "Another channel seen in these patches had longer open times, exhibited
prominent channel noise, was inwardly rectifying at strongly depolarized
potentials, and had a mean conductance of 20.3 +- 1.2 pS (n = 7; Fig. 3).
Ensemble averages of this current gave pure I(K)-like currents in different
patches, both inactivating (n = 3; Figs 1C and 3A) and non-inactivating
variants (n = 4; Fig. 1B). Thus it appears that a single type of channel
underlies the different forms of the slow, I(K)-like current, but its
inactivation properties may vary.".pp.613-614

"For convenience, the fast transient and slowly inactivating/non-inactivating
currents seen in these patches will henceforth be called I(A) and I(K),
respectively."p.614 		Fig. 1, 3 pp.613-614 - 1006622979 -625879160
-558364987 -558364987 -1671068009 gCaL Ca2+ 3.0 mS/cm^2 - - - - Table A1,A2 p.919 Full kinetic description of model conductance -1671068009 -558364987
-558364987 -558364987 -1671068009 gCaT Ca2+ 0.1 mS/cm^2 - - - - Table A1,A2 p.919 Full kinetic description of model conductance -1671068009 -558364987
-558364987 -558364987 -1671068009 gH Cations 0.25 mS/cm^2 - - - - Table A1,A2 p.919 Full kinetic description of model conductance -1671068009 -558364987
-558364987 -558364987 -1671068009 gK2 K+ 0.1 mS/cm^2 - - - - Table A1,A2 p.919 Full kinetic description of model conductance -1671068009 -558364987
-558364987 -558364987 -1671068009 gKA K+ 2 mS/cm^2 - - - - Table A1,A2 p.919 Full kinetic description of model conductance -1671068009 -558364987
-558364987 -558364987 -1671068009 gKAHP K+ 0.1 mS/cm^2 - - - - Table A1,A2 p.919 Full kinetic description of model conductance -1671068009 -558364987
-558364987 -558364987 -1671068009 gKM K+ 7.5 mS/cm^2 - - - - Table A1,A2 p.919 Full kinetic description of model conductance -1671068009 -558364987
-558364987 -558364987 -1671068009 gNaP Na+ DNaP*0.0032*gNaT - - - - Table A1,A2 p.919 Full kinetic description of model conductance -1671068009 -558364987
-558364987 -558364987 -1671068009 gNaT Na+ 6.25 ms/cm^2 - - - - Table A1,A2 p.919 Full kinetic description of model conductance -1671068009 -558364987
998919415 998919415 998918972 BK K+ 181.6+-3.9 pS - - - "Three hundred ninety-six slow-gating ("slow") and 9 fast-gating ("fast") BK
channels were observed in 218 inside-out patches excised from P0-P28 neurons.
The slow channel, which was the most prominent type in both mature and
immature neurons, has properties similar to those expected for BK channels
(Farley and Rudy 1988; Reinhart et al. 1989). However, fast channels were only
observed in immature neurons."p.4195 		Fig. 1(A,B), 2(A,B), 3 pp.4195-4196 Data on timeconstants, open-probabilities and calcium-dependency in text and
figures. 		998918972 998919415
1006790213 1006790213 83751301 BK K+ ~150 pS - - - "The types and densities of K+ channels along the apical dendrite were also
investigated with cell-attached recordings. ... Considerable variability was
observd between patches along the apical dendrite. Out of the 61 patches along
the dendrite 10 did not have any outward current and 14 displayed currents
that appeared to result from the activation of a single channel. In another 28
patches it was possible to observe, in some sweeps, unitary channel openings
even when the patch contained more than one channel. ... Channel openings that
could be clearly differentiated were associated by their unitary current
magnitude to one of the three types observed at the soma. ... The peak
amplitude of the ensemble K+ current changed as a function of the distance
from the soma (Fig. 13A) with a slope of -0.9 +- 0.3 pA(100µm)^-1 with a
statistically significant (P < 0.01) Spearman rank order correlation
coefficient of -0.3. The distribution of these channels as a function of the
distance from the soma is shown in Fig. 13A."pp.633-635 		- p.635 - 83751301 1006790213
1006790213 1006790213 83751301 K(fast inact.) K+ 13 +- 1 pS - - - "In three patches channel openings were observed with short first latency (Fig.
9A). Following several openings the channels entered a long closed duration
(Fig. 9A). The unitary conductance of this channel was 13 +- 1 pS (Fig. 9C, n
= 3). Ensemble currents revealed a fast inactivating current (Fig. 9B). The
decay of the current was fitted to a single exponent with time constants of 36
ms at 60 mV above the resting membrane potential, 28 ms at 80 mV and 34 ms at
100 mV (Fig. 9B). Similar time constants were observed in two or more patches
that also contained other types of channels (see also Fig. 12). This
inactivation time constant was four times larger than the time constant
obtained in this voltage range fir the fast K+ current in nucleated patches
(Figs 1 and 6)."pp.631-632 		Fig. 9, 12 pp.631-632 - 83751301 1006790213
1006790213 1006790213 83751301 K(slow inact.) K+ 9.5 +- 0.5 pS - - - "Channels that displayed a long latency to the first opening, when the voltage
was stepped to 40 mV above the resting membrane potential (Fig. 11A), were
observed in three additional patches. The unitary channel current at this
voltage was smaller than that observed for the delayed channel described in
Fig. 10. The unitary conductance of this channel was 9.5 +- 0.5 pS (Fig. 11C,
n = 3). The rate of inactivation of these channels was faster than that found
for the 16 pS channel (Fig. 10). The inactivation time constant, determined
from ensemble currents, was 190 ms at 40 mV above the resting membrane
potential, 130 ms at 60 mV, and 200 ms at 80 mV (Fig. 11B). The inactivation
time constant 120 mV above the resting membrane potential was calculated to be
250 +- 50 ms (n = 3). These values were similar to the faster inactivation
time constant of the slow K+ current in nucleated patches (Fig. 8)."pp.632-633 		Fig. 11 pp.632-633 - 83751301 1006790213
1006790213 1006790213 83751301 K(very slow inact.) K+ 16 +- 1 pS - - - "In four patches a channel that displayed a long latency to the first opening
when the voltage was stepped to 40 mV above the resting membrane potential
(Fig. 10A) was observed. Burst duration increased while the intra-burst closed
time decreased as a function of the applied voltage (Fig. 10A). The unitary
conductance of this channel was 16 +- 1 pS (Fig.10B, n = 4). A long closed
duration was observed in most traces when voltage steps of 5s to +60 mV above
the resting membrane potential were applied (Fig. 10C). Summation of 45 sweeps
revealed a slowly inactivating ensemble current (Fig. 10C). The decay of the
ensemble current was best fitted to a single exponent with a time constant of
5.5 +- 2 s at +60 mV above the resting membrane potential (n = 3). This time
constant was similar to the slow time constant of the macroscopic current in
nucleated patches zero mV (3.5 +- 0.8 ms, n = 6, Fig. 8)."p.632 		Fig. 10 p.632 - 83751301 1006790213
1006932736 1006932736 83751301 BK K+ ~150 pS - - - "In four patches (two somatic and two dendritic at 60 and 300 µm) a fourth type
of K+ channel was observed. This K+ channel had a unitary conductance of
approximately 150 pS (n = 2) matching that of the large conductance
Ca2+-activated K+ (BK) channels observed in dissociated neocortical pyramidal
neurones (Kang et al. 1996). The low frequency of occurence of this K+ channel
subtype may be due to a lower channel density than the one reported for
dissociated neocortical pyramidal neurones (Kang et al. 1996) or to a low
channel opening probability due to a low intracellular Ca2+
concentration."p.635 		- p.635 - 83751301 1006932736
1006932736 1006932736 83751301 K K+ 4-17 ps/µm^2 - - - "The types and densities of K+ channels along the apical dendrite were also
investigated with cell-attached recordings. ... Considerable variability was
observd between patches along the apical dendrite. Out of the 61 patches along
the dendrite 10 did not have any outward current and 14 displayed currents
that appeared to result from the activation of a single channel. In another 28
patches it was possible to observe, in some sweeps, unitary channel openings
even when the patch contained more than one channel. ... Channel openings that
could be clearly differentiated were associated by their unitary current
magnitude to one of the three types observed at the soma. ... The peak
amplitude of the ensemble K+ current changed as a function of the distance
from the soma (Fig. 13A) with a slope of -0.9 +- 0.3 pA(100µm)^-1 with a
statistically significant (P < 0.01) Spearman rank order correlation
coefficient of -0.3. The distribution of these channels as a function of the
distance from the soma is shown in Fig. 13A."pp.633-635 		Fig. 13 pp.633-636 - 83751301 1006932736
1064194824 1064194824 -1671068009 gCaL Ca2+ 0.5 mS/cm^2 - - - - Table A1, A2 p.919 Full kinetic description of model conductance -1671068009 1064194824
1064194824 1064194824 -1671068009 gCaT Ca2+ 0.1 mS/cm^2 - - - - Table A1, A2 p.919 Full kinetic description of model conductance -1671068009 1064194824
1064194824 1064194824 -1671068009 gH Cations 0.25 mS/cm^2 - - - - Table A1, A2 p.919 Full kinetic description of model conductance -1671068009 1064194824
1064194824 1064194824 -1671068009 gK2 K+ 0.1 mS/cm^2 - - - - Table A1, A2 p.919 Full kinetic description of model conductance -1671068009 1064194824
1064194824 1064194824 -1671068009 gKA K+ 30 mS/cm^2 - - - - Table A1, A2 p.919 Full kinetic description of model conductance -1671068009 1064194824
1064194824 1064194824 -1671068009 gKAHP K+ 0.1 mS/cm^2 - - - - Table A1, A2 p.919 Full kinetic description of model conductance -1671068009 1064194824
1064194824 1064194824 -1671068009 gKC K+ DKC*12 - - - - Table A1, A2 p.919 Full kinetic description of model conductance -1671068009 1064194824
1064194824 1064194824 -1671068009 gKDr K+ 125 mS/cm^2 - - - - Table A1, A2 p.919 Full kinetic description of model conductance -1671068009 1064194824
1064194824 1064194824 -1671068009 gKM K+ 7.5 mS/cm^2 - - - - Table A1, A2 p.919 Full kinetic description of model conductance -1671068009 1064194824
1064194824 1064194824 -1671068009 gNaP Na+ DNaP*0.0032*gNaT - - - - Table A1, A2 p.919 Full kinetic description of model conductance -1671068009 1064194824
1064194824 1064194824 -1671068009 gNaT Na+ 187.5 mS/cm^2 - - - - Table A1, A2 p.919 Full kinetic description of model conductance -1671068009 1064194824
1064204721 1064204721 -1671068009 gK2 K+ 0.1 mS/cm^2 - - - - Table A1, A2 p.919 Full kinetic description of model conductance -1671068009 1064204721
1064204721 1064204721 -1671068009 gKA K+ 2 mS/cm^2 - - - - Table A1, A2 p.919 Full kinetic description of model conductance -1671068009 1064204721
1064204721 1064204721 -1671068009 gKDr K+ 400 mS/cm^2 - - - - Table A1, A2 p.919 Full kinetic description of model conductance -1671068009 1064204721
1064204721 1064204721 -1671068009 gNaT Na+ 400 mS/cm^2 - - - - Table A1, A2 p.919 Full kinetic description of model conductance -1671068009 1064204721
1064206191 1064206191 -1671068009 gKA K+ 30 mS/cm^2 - - - - Table A1,A2 p.919 Full kinetic description of model conductance -1671068009 1064206191
1064206420 1064206420 -1671068009 gCaL Ca2+ 0.5 mS/cm^2 - - - - Table A1,A2 p.919 Full kinetic description of model conductance -1671068009 1064206420
1064206420 1064206420 -1671068009 gCaT Ca2+ 0.1 mS/cm^2 - - - - Table A1,A2 p.919 Full kinetic description of model conductance -1671068009 1064206420
1064206420 1064206420 -1671068009 gH Cations 0.25 mS/cm^2 - - - - Table A1,A2 p.919 Full kinetic description of model conductance -1671068009 1064206420
1064206420 1064206420 -1671068009 gK2 K+ 0.1 mS/cm^2 - - - - Table A1,A2 p.919 Full kinetic description of model conductance -1671068009 1064206420
1064206420 1064206420 -1671068009 gKA K+ 2 mS/cm^2 - - - - Table A1,A2 p.919 Full kinetic description of model conductance -1671068009 1064206420
1064206420 1064206420 -1671068009 gKAHP K+ 0.1 mS/cm^2 - - - - Table A1,A2 p.919 Full kinetic description of model conductance -1671068009 1064206420
1064206420 1064206420 -1671068009 gKC K+ DKC*12 - - - - Table A1,A2 p.919 Full kinetic description of model conductance -1671068009 1064206420
1064206420 1064206420 -1671068009 gKDr K+ 93.75 ms/cm^2 - - - - Table A1,A2 p.919 Full kinetic description of model conductance -1671068009 1064206420
1064206420 1064206420 -1671068009 gKM K+ 7.5 mS/cm^2 - - - - Table A1,A2 p.919 Full kinetic description of model conductance -1671068009 1064206420
1064206420 1064206420 -1671068009 gNaP Na+ DNaP*0.0032*gNaT - - - - Table A1,A2 p.919 Full kinetic description of model conductance -1671068009 1064206420
1064206420 1064206420 -1671068009 gNaT Na+ 125 & 93.75 ms/cm^2 - - - - Table A1,A2 p.919 Full kinetic description of model conductance -1671068009 1064206420
1927746281 1927746281 1006622979 I(A) K+ - - -22.9 +- 3.6 mV - "...and V(1/2)-22.9 +- 3.6 mV and k = 16.2 +- 0.8 mV (n = 4) for patches > 250
µm from the soma (Fig. 4B, open circles)."p.614 		Fig. 4 p.614 More parameters on activation/inactivation and timeconstants given. 1006622979 1927746281