Ca2+ signaling by T-type Ca2+ channels in neurons

Cueni, Lucius; Canepari, Marco; Adelman, John P.; Lüthi, Anita

doi:10.1007/s00424-008-0582-6

Cited by 58 publications

(46 citation statements)

References 118 publications

(213 reference statements)

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“…T-channels may further tune responses to afferent inputs by modulating hyperpolarizing K ϩ currents. Calcium influx through T-channels modulates gating of small-conductance Ca 2ϩ -activated potassium (SK) channels (Cueni et al 2009), which are strongly expressed in the dorsal horn (Mongan et al 2005). Activation of SK channels decreases neuronal excitability by increasing firing adaptation to membrane depolarization (Stoker 2004) and may represent another means for sharpening dorsal horn neuronal responses to transient stimuli.…”

Section: Discussionmentioning

confidence: 99%

Multiple T-type Ca²⁺ current subtypes in electrophysiologically characterized hamster dorsal horn neurons: possible role in spinal sensory integration

Ku¹,

Schneider

2011

Journal of Neurophysiology

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Whole cell patch-clamp recordings were used to investigate the contribution of transient, low-threshold calcium currents (I(T)) to firing properties of hamster spinal dorsal horn neurons. I(T) was widely, though not uniformly, expressed by cells in Rexed's laminae I-IV and correlated with the pattern of action potential discharge evoked under current-clamp conditions: I(T) in neurons responding to constant membrane depolarization with one or two action potentials was nearly threefold larger than I(T) in cells responding to the same activation with continuous firing. I(T) was evoked by depolarizing voltage ramps exceeding 46 mV/s and increased with ramp slope (240-2,400 mV/s). Bath application of 200 μM Ni(2+) depressed ramp-activated I(T). Phasic firing recorded in current clamp could only be activated by membrane depolarizations exceeding ∼43-46 mV/s and was blocked by Ni(2+) and mibefradil, suggesting I(T) as an underlying mechanism. Two components of I(T), "fast" and "slow," were isolated based on a difference in time constant of inactivation (12 ms and 177 ms, respectively). The amplitude of the fast subtype depended on the slope of membrane depolarization and was twice as great in burst-firing cells than in cells having a tonic discharge. Post hoc single-cell RT-PCR analyses suggested that the fast component is associated with the Ca(V)3.1 channel subtype. I(T) may enhance responses of phasic-firing dorsal horn neurons to rapid membrane depolarizations and contribute to an ability to discriminate between afferent sensory inputs that encode high- and low-frequency stimulus information.

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Section: Discussionmentioning

confidence: 99%

Multiple T-type Ca²⁺ current subtypes in electrophysiologically characterized hamster dorsal horn neurons: possible role in spinal sensory integration

Ku¹,

Schneider

2011

Journal of Neurophysiology

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“…Ca 2+ -activated K + (K Ca ) channels Ca 2+ -activated K + (K Ca ) channels are present in excitable and non-excitable cells (Stocker and Pedarzani, 2000;Stocker, 2004;Pedarzani and Stocker, 2008;Cueni et al, 2009;Faber, 2009). These channels open on activation by low concentrations of Ca 2+ , resulting in hyperpolarization of the membrane potential and changes in cellular excitability (Wei et al, 2005).…”

Section: Voltage-gated K + (K V ) Channelsmentioning

confidence: 98%

Organisation of potassium channels on the neuronal surface

Luján

2010

Journal of Chemical Neuroanatomy

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“…A critical component of the network mediating waves and a primary source of depolarizing input to RGCs is glutamate release from bipolar cells (Firl et al , 2013; Akrouh & Kerschensteiner, 2013). In the adult retina, bipolar cells exhibit unstable membrane potentials and their spontaneous depolarizations are mediated by low-voltage activated T-type calcium channels (Ma & Pan, 2003; Cueni et al , 2009; Sargoy et al , 2014; Puthussery et al , 2014) that are expressed in subsets of bipolar cells (Pan et al , 2001; Singer & Diamond, 2003) and of ganglion cells (Sargoy et al , 2014). The isoform α1 H (Ca V 3.2) of the T-type Ca 2+ channel (Cueni et al , 2009) localizes to cone bipolar cells.…”

Section: Introductionmentioning

confidence: 99%

CaV3.2 KO mice have altered retinal waves but normal direction selectivity

et al. 2015

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Early in development, before the onset of vision, the retina establishes direction-selective responses. During this time period, the retina spontaneously generates bursts of action potentials that propagate across its extent. The precise spatial and temporal properties of these “retinal waves” have been implicated in the formation of retinal projections to the brain. However their role in the development of direction selective circuits within the retina has not yet been determined. We addressed this issue by combining multi-electrode array and cell-attached recordings to examine mice that lack the CaV3.2 subunit of T-type Ca2+ channels (CaV3.2 KO) because these mice exhibit disrupted waves during the period that direction selective circuits are established. We found that the spontaneous activity of these mice displays wave-associated bursts of action potentials that are altered from control mice: the frequency of these bursts is significantly decreased and the firing rate within each burst is reduced. Moreover, the retina’s projection patterns demonstrate decreased eye-specific segregation in the dLGN. However, after eye-opening, the direction selective responses of CaV3.2 KO DSGCs are indistinguishable from those of wild-type DSGCs. Our data indicate that, although the temporal properties of the action potential bursts associated with retinal waves are important for activity-dependent refining of retinal projections to central targets, they are not critical for establishing direction selectivity in the retina.

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Ca2+ signaling by T-type Ca2+ channels in neurons

Abstract: Among the major families of voltage-gated Ca 2+

Cited by 58 publications

References 118 publications

Multiple T-type Ca²⁺ current subtypes in electrophysiologically characterized hamster dorsal horn neurons: possible role in spinal sensory integration

Multiple T-type Ca²⁺ current subtypes in electrophysiologically characterized hamster dorsal horn neurons: possible role in spinal sensory integration

Organisation of potassium channels on the neuronal surface

CaV3.2 KO mice have altered retinal waves but normal direction selectivity

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Ca2+ signaling by T-type Ca2+ channels in neurons

Abstract: Among the major families of voltage-gated Ca 2+

Cited by 58 publications

References 118 publications

Multiple T-type Ca2+ current subtypes in electrophysiologically characterized hamster dorsal horn neurons: possible role in spinal sensory integration

Multiple T-type Ca2+ current subtypes in electrophysiologically characterized hamster dorsal horn neurons: possible role in spinal sensory integration

Organisation of potassium channels on the neuronal surface

CaV3.2 KO mice have altered retinal waves but normal direction selectivity

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Multiple T-type Ca²⁺ current subtypes in electrophysiologically characterized hamster dorsal horn neurons: possible role in spinal sensory integration

Multiple T-type Ca²⁺ current subtypes in electrophysiologically characterized hamster dorsal horn neurons: possible role in spinal sensory integration