Ca2+ channels that activate Ca2+-dependent K+ currents in neostriatal neurons

Vilchis, Carmen; Bargas, José; Ayala, Gabriela X.; Galván, Emilio J.; Galarraga, Elvira

doi:10.1016/s0306-4522(99)00493-5

Cited by 58 publications

(38 citation statements)

References 46 publications

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“…The sAHP current is activated by calcium entry through Ca v 1 (L-type) channels, the mAHP current through SK channels is activated by calcium entry through and Ca v 2.2 (N-type) channels, and the contribution of the BK currents to spike repolarization is activated by calcium influx through Ca v 2.1 channels (apparently of the Q type). Each of these examples of specific coupling can be found individually in other neurons (Viana et al, 1993;Tanabe et al, 1998), but the rules of preferential coupling of calcium channels to AHPs are, in general, diverse and cell-type specific (Viana et al, 1993;Sah, 1995;Williams et al, 1997;Marrion and Tavalin, 1998;Pineda et al, 1998;Shah and Haylett, 2000;Vilchis et al, 2000;Cloues and Sather, 2003). Studying this selectivity in cholinergic interneurons provides a unique opportunity to probe the context in which it is played out (i.e., in modulating the ongoing firing patterns exhibited by these neurons).…”

Section: Discussionmentioning

confidence: 99%

“…Several such cal-cium channels have been shown to contribute to barium currents recorded from dissociated cholinergic interneurons (Yan and Surmeier, 1996). One possible function for a diversity of calcium currents is the selective coupling of these channels to calciumdependent potassium channels (Viana et al, 1993;Sah, 1995;Williams et al, 1997;Marrion and Tavalin, 1998;Pineda et al, 1998;Shah and Haylett, 2000;Vilchis et al, 2000;Cloues and Sather, 2003). Because the calcium currents in cholinergic interneurons are targets of neuromodulation (Yan and Surmeier, 1996;Yan et al, 1997;Song et al, 2000;Pisani et al, 2002), finding such a selective coupling would provide a possible mechanism by which the firing patterns and the cholinergic output of these neurons are controlled by neuromodulators.…”

Section: Introductionmentioning

confidence: 99%

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Control of Spontaneous Firing Patterns by the Selective Coupling of Calcium Currents to Calcium-Activated Potassium Currents in Striatal Cholinergic Interneurons

Goldberg¹,

Wilson²

2005

J. Neurosci.

148

182

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The spontaneous firing patterns of striatal cholinergic interneurons are sculpted by potassium currents that give rise to prominent afterhyperpolarizations (AHPs). Large-conductance calcium-activated potassium (BK) channel currents contribute to action potential (AP) repolarization; small-conductance calcium-activated potassium channel currents generate an apamin-sensitive medium AHP (mAHP) after each AP; and bursts of APs generate long-lasting slow AHPs (sAHPs) attributable to apamin-insensitive currents. Because all these currents are calcium dependent, we conducted voltage-and current-clamp whole-cell recordings while pharmacologically manipulating calcium channels of the plasma membrane and intracellular stores to determine what sources of calcium activate the currents underlying AP repolarization and the AHPs. The Ca v 2.2 (N-type) blocker -conotoxin GVIA (1 M) was the only blocker that significantly reduced the mAHP, and it induced a transition to rhythmic bursting in one-third of the cells tested. Ca v 1 (L-type) blockers (10 M dihydropyridines) were the only ones that significantly reduced the sAHP. When applied to cells induced to burst with apamin, dihydropyridines reduced the sAHPs and abolished bursting. Depletion of intracellular stores with 10 mM caffeine also significantly reduced the sAHP current and reversibly regularized firing. Application of 1 M -conotoxin MVIIC (a Ca v 2.1/2.2 blocker) broadened APs but had a negligible effect on APs in cells in which BK channels were already blocked by submillimolar tetraethylammonium chloride, indicating that Ca v 2.1 (Q-type) channels provide the calcium to activate BK channels that repolarize the AP. Thus, calcium currents are selectively coupled to the calcium-dependent potassium currents underlying the AHPs, thereby creating mechanisms for control of the spontaneous firing patterns of these neurons.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Control of Spontaneous Firing Patterns by the Selective Coupling of Calcium Currents to Calcium-Activated Potassium Currents in Striatal Cholinergic Interneurons

Goldberg¹,

Wilson²

2005

J. Neurosci.

148

182

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“…PKA has been shown to increase L-type Ca 2+ channel currents (Gao et al 1997;Hernandez-Lopez et al 1997) and decrease somatic K + currents (Kitai and Surmeier 1993). Furthermore, activation of the D 1 receptor reduces GABA A receptor currents through a PKA/ DARPP-32/PP1 signaling cascade (Flores-Hernandez et al 2000), and D 1 receptor signaling inhibits the opening of the Ca v 2 Ca 2+ channels that activate Ca 2+ -dependent small conductance K + channels (Vilchis et al 2000). Overall, the dopamine modulation on direct-pathway MSNs serves to increase spiking and somatic depolarization.…”

Section: Thalamostriatal Circuitmentioning

confidence: 99%

Functional roles of neurotransmitters and neuromodulators in the dorsal striatum

Kim

Bakes

et al. 2012

Learn. Mem.

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The dorsal striatum, with its functional microcircuits galore, serves as the primary gateway of the basal ganglia and is known to play a key role in implicit learning. Initially, excitatory inputs from the cortex and thalamus arrive on the direct and indirect pathways, where the precise flow of information is then regulated by local GABAergic interneurons. The balance of excitatory and inhibitory transmission in the dorsal striatum is modulated by neuromodulators such as dopamine and acetylcholine. Under pathophysiological states in the dorsal striatum, an alteration in excitatory and inhibitory transmission may underlie dysfunctional motor control. Here, we review the cellular connections and modulation of striatal microcircuits and propose that modulating the excitatory and inhibitory balance in synaptic transmission of the dorsal striatum is important for regulating locomotion.The dorsal striatum is best known for its role in decision-making, especially in action selection and initiation through the convergence of sensorimotor, cognitive, and motivational information (DeLong 1990;Smith et al. 1998;Balleine et al. 2007). As the primary input of the basal ganglia, the striatum receives glutamatergic inputs from the cortex and thalamus and in turn projects GABAergic outputs to the globus pallidus and substantia nigra pars reticulata (SNr). Inputs from the cortex and thalamus both form excitatory synaptic connections on medium spiny neurons (MSN) in which cortical afferents are from the sensory, motor, and associational cortex (Bolam et al. 2000), and thalamic afferents are from the intralaminar thalamic nuclei (Doig et al. 2010). These glutamatergic inputs are then processed in the dorsal striatum where numerous connections between various types of neurons exist. Thus, the complexity of neuronal circuits has made it difficult to elucidate the functional roles of the striatum. Recently, studies focused on interneurons that reside in the dorsal striatum have characterized the physiological features and functional connections. For example, parvalbumin-expressing fastspiking interneurons (PV-FSI) and neuropeptide-Y positive lowthreshold spiking interneurons (NPY-LTS) form synaptic connections with MSNs and regulate the firing activity of the principal neuron MSNs (Koos and Tepper 1999;Gittis et al. 2010;Chuhma et al. 2011). These interneurons were shown to have distinct firing patterns and connections, and thus they may exert different effects on MSNs. Other crucial connections are the cholinergic, dopaminergic, and serotonergic axons that strongly innervate the dorsal striatum. These projections are essential for modulating striatal circuits and disruption of such signaling can result in movement impairments and neurological disorders such as Huntington's disease (Lovinger 2010). This review summarizes recent reports of the microcircuits present in the dorsal striatum, although serotonergic signaling is excluded, and suggests a putative role for striatal microcircuits in motor dysfunction and/or hyperactivity that ...

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“…-dependent K + -currents that make up the after hyperpolarizing potential (AHP) and thus the interspike intervals (ISIs) [4]. Therefore, suppressing this Ca 2+ -source would reduce ISIs and make firing frequency to increase [5].…”

Section: +mentioning

confidence: 99%

“…Ca V 1 channels increase excitability by regulating threshold and neuronal discharge, while Ca V 2 channels decrease excitability by activating K + -activated currents that regulate inter-spike intervals, firing frequency, and transmitter release [4][5][6], among other actions. For example, in addition to many other functions [7], D 1 -receptors increase excitability in dSPNs by enhancing Ca V 1-channels mediated current, while D 2 -receptors decrease excitability in iSPNs by reducing the same current [8,9].…”

Section: Introductionmentioning

confidence: 99%

Modulation of Ca2+-currents by sequential and simultaneous activation of adenosine A1 and A2A receptors in striatal projection neurons

Hernández-González

Hernández-Flores

Prieto

et al. 2013

Purinergic Signalling

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Ca2+ channels that activate Ca2+-dependent K+ currents in neostriatal neurons

Cited by 58 publications

References 46 publications

Control of Spontaneous Firing Patterns by the Selective Coupling of Calcium Currents to Calcium-Activated Potassium Currents in Striatal Cholinergic Interneurons

Control of Spontaneous Firing Patterns by the Selective Coupling of Calcium Currents to Calcium-Activated Potassium Currents in Striatal Cholinergic Interneurons

Functional roles of neurotransmitters and neuromodulators in the dorsal striatum

Modulation of Ca2+-currents by sequential and simultaneous activation of adenosine A1 and A2A receptors in striatal projection neurons

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