Outward Currents Influencing Bursting Dynamics in Guinea Pig Trigeminal Motoneurons

Negro, Christopher A. Del; Hsiao, Chie-Fang; Chandler, Scott H.

doi:10.1152/jn.1999.81.4.1478

Cited by 54 publications

(43 citation statements)

References 46 publications

(68 reference statements)

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“…P/Q-type calcium channels play an essential role in regulating burst firing in Purkinje neurons. High-and low-threshold voltage-gated calcium channels also contribute to bursting in other neurons (Huguenard, 1996;Del Negro et al, 1999). In each of these cases, activation of the calcium channels contributes a depolarizing current that helps bring the cell to threshold during the bursts.…”

Section: Discussionmentioning

confidence: 99%

“…In each of these cases, activation of the calcium channels contributes a depolarizing current that helps bring the cell to threshold during the bursts. Bursts are terminated by inactivation of the calcium channels (Kramer and Zucker, 1985;Huguenard and Prince, 1992;Bal and McCormick, 1997) or by activation of calciumactivated potassium channels after calcium entry (Wong and Prince, 1978;Del Negro et al, 1999;Golding et al, 1999). In Purkinje neurons, however, P/Q-type calcium channels are responsible for the abrupt termination of each burst by generating a dendritic calcium spike.…”

Section: Discussionmentioning

confidence: 99%

“…To explore further the mechanism of burst firing in Purkinje cells, we used selective blockers to evaluate whether specific voltage-or calcium-activated channels are required for spontaneous bursting. Specifically, we investigated the role of T-type calcium channels, hyperpolarization-activated channels, and SK and BK conductance calciumactivated potassium channels because these conductances have been shown to play a significant role in bursting in other cells (Huguenard, 1996;Luthi and McCormick, 1998;Del Negro et al, 1999;Grillner et al, 2001) or in dissociated Purkinje neurons (Swensen and Bean, 2003).…”

Section: Contribution Of Ion Channels To Burstingmentioning

confidence: 99%

“…Calcium-activated potassium channels have been shown to contribute to bursting (Pape and Driesang, 1998;Del Negro et al, 1999;Grillner et al, 2001). Both SK and BK channels are present in Purkinje neurons (Jacquin and Gruol, 1999;Cingolani et al, 2002;Edgerton and Reinhart, 2003;Khodakhah, 2002b, 2003) and both contribute to burst firing in dissociated Purkinje cells (Swensen and Bean, 2003).…”

Section: Sk Channels Contribute To Interspike and Interburst Intervalsmentioning

confidence: 99%

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Dendritic Control of Spontaneous Bursting in Cerebellar Purkinje Cells

Womack¹,

Khodakhah²

2004

J. Neurosci.

123

128

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We investigated the mechanisms that contribute to spontaneous regular bursting in adult Purkinje neurons in acutely prepared cerebellar slices. Bursts consisted of 3-20 spikes and showed a stereotypic waveform. Each burst developed with an increase in firing rate and was terminated by a more rapid increase in firing rate and a decrease in spike height. Whole-cell current-clamp recordings showed that each burst ended with a rapid depolarization followed by a hyperpolarization. Dual dendritic and somatic extracellular recordings revealed that each burst was terminated by a dendritic calcium spike. The contributions of T-and P/Q-type calcium current, large (BK) and small (SK) conductance calcium-activated potassium currents, and hyperpolarization-activated (I H ) current to bursting were investigated with specific channel blockers. None of the currents, except for P/Q, were required to sustain spontaneous bursting or the stereotypic burst waveform. T-type calcium, BK, and SK channels contributed to interspike and interburst intervals. The effect of T-type calcium channel block was more pronounced after BK channel block and vice versa, indicating that these two currents interact to regulate burst firing. Block of I H current had no effect on bursting. Partial block of P/Q-type calcium channels concurrently eliminated dendritic calcium spikes and caused a switch from regular bursting to tonic firing or irregular bursting. Dendritic calcium spikes persisted in the presence of tetrodotoxin, indicating that their initiation did not require somatic sodium spikes. Our results demonstrate an important role for dendritic conductances in burst firing in intact Purkinje neurons.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Contribution Of Ion Channels To Burstingmentioning

confidence: 99%

Section: Sk Channels Contribute To Interspike and Interburst Intervalsmentioning

confidence: 99%

See 2 more Smart Citations

Dendritic Control of Spontaneous Bursting in Cerebellar Purkinje Cells

Womack¹,

Khodakhah²

2004

J. Neurosci.

123

128

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“…In addition, the electrogenic nature of the sodium pump should also contribute to regulate membrane potentials and neuronal firing. For example, activation of sodium pump currents have been shown to underlie the N-methyl-D-aspartate (NMDA)-induced burst firing in the midbrain dopamine neurons (Johnson et al 1992) and the strychnine-and bicucullineinduced burst firing in the neonatal rat spinal cord (Ballerini et al 1997), to mediate the prolonged hyperpolarization after glutamate-induced depolarization in hippocampal CA1 neurons (Thompson and Prince 1986), and to be involved in rhythm generation in cultured spinal networks (Darbon et al 2003) and in burst dynamics in trigeminal motoneurons (Del Negro et al 1999).…”

Section: Introductionmentioning

confidence: 99%

Effects of Sodium Pump Activity on Spontaneous Firing in Neurons of the Rat Suprachiasmatic Nucleus

Wang¹,

Huang²

2006

Journal of Neurophysiology

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. Effects of sodium pump activity on spontaneous firing in neurons of the rat suprachiasmatic nucleus. J Neurophysiol 96: 109 -118, 2006. First published February 8, 2006 doi:10.1152/jn.01369.2005. Cell-attached and whole cell recording techniques were used to study the effects of electrogenic sodium pump on the excitability of rat suprachiasmatic nucleus (SCN) neurons. Blocking the sodium pump with the cardiac steroid strophanthidin or zero K ϩ increased the spontaneous firing of SCN neurons to different degrees with different recording modes, whereas turning the sodium pump into a nonselective cation channel with the marine toxin palytoxin invariably increased the spontaneous firing to the point of total blockade. Current-clamp recordings indicated that strophanthidin increased the rate of membrane depolarization and reduced the peak afterhyperpolarization potential (AHP), whereas zero K ϩ also increased the rate of depolarization, but enhanced the peak AHP. The dual effect of zero K ϩ was reflected by the biphasic time course of voltage responses to zero K ϩ : an inhibitory phase with enhanced peak AHP and slower firing, followed by a delayed excitatory phase with faster rate of membrane depolarization and faster firing. In the presence of strophanthidin to block the sodium pump, zero K ϩ consistently decreased firing by enhancing the peak AHP. Repetitive applications of K ϩ -free solution gradually turned the biphasic inhibitory-followed-by-excitatory voltage response into a monophasic inhibitory response in cells recorded with the whole cell (but not the cell-attached) mode, suggesting rundown of sodium pump activity. Taken together, the results suggest that spontaneous firing of SCN neurons is regulated by sodium pump activity as well as the AHP, and that sodium pump activity is modulated by intracellular soluble substances subject to rundown under the whole cell conditions.

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Intrinsic membrane properties and morphological characteristics of interneurons in the rat supratrigeminal region

Hsiao

Gougar

Asai

et al. 2007

J of Neuroscience Research

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The membrane properties and morphological features of interneurons in the supratrigeminal area (SupV) were studied in rat brain slices using whole-cell patch clamp recording techniques. We classified three morphological types of neurons as fusiform, pyramidal, and multipolar and four physiological types of neurons according to their discharge pattern in response to a 1-sec depolarizing current pulse from -80 mV. Single-spike neurons responded with a single spike, phasic neurons showed an initial burst of spikes and were silent during the remainder of the stimulus, delayed-firing (DF) neurons exhibited a slow depolarization and delay to initial spike onset, and tonic (T) neurons showed maintained a discharge throughout the stimulus pulse. In a subpopulation of neurons (10%), membrane depolarization to around -44 mV produced a rhythmic burst discharge (RB) that was associated with voltage-dependent subthreshold membrane oscillations. Both these phenomena were blocked by the sodium channel blocker riluzole at a concentration that did not affect the fast transient spike. Low doses of 4-AP, which blocks low-threshold K+ currents, transformed bursting into low-frequency tonic discharge. In contrast, bursting occurred with exposure to cadium, a calcium-channel blocker. This suggests that persistent sodium currents and low-threshold K+ currents have a role in intrinsic burst generation. Importantly, RB cells were most often associated with multipolar neurons that exhibited either a DF or a T discharge. Thus, the SupV contains a variety of physiological cell types with unique morphologies and discharge characteristics. Intrinsic bursting neurons form a unique group in this region. .

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Outward Currents Influencing Bursting Dynamics in Guinea Pig Trigeminal Motoneurons

Cited by 54 publications

References 46 publications

Dendritic Control of Spontaneous Bursting in Cerebellar Purkinje Cells

Dendritic Control of Spontaneous Bursting in Cerebellar Purkinje Cells

Effects of Sodium Pump Activity on Spontaneous Firing in Neurons of the Rat Suprachiasmatic Nucleus

Intrinsic membrane properties and morphological characteristics of interneurons in the rat supratrigeminal region

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