Aspects of calcium-activated chloride currents: A neuronal perspective

Scott, Roderick H.; Sutton, Kathy G.; Griffin, Andrew; Stapleton, Simon; Currie, Kevin P. M.

doi:10.1016/0163-7258(95)00018-c

Cited by 68 publications

(49 citation statements)

References 152 publications

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“…To determine the nature of this desensitized outward current, we examined its sensitivity to various ions. Because NMDA receptors can be coupled to calcium-dependent chloride channels (Scott et al, 1995), we studied the NMDA effects in a Cl Ϫ -free solution in class II neurons. In control solution, coapplication of NMDA and glycine onto these neurons evoked an outward current around Ϫ20 mV.…”

Section: Resultsmentioning

confidence: 99%

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Electrophysiological Evidence for Expression of Glycine Receptors in Freshly Isolated Neurons from Nucleus Accumbens

Martin

Siggins²

2002

The Journal of Pharmacology and Experimental Therapeutics

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In the course of studying N-methyl-D-aspartate (NMDA) receptors of the nucleus accumbens (NAcc), we found that 20% of freshly isolated medium spiny neurons, as well as all interneurons, responded in an unexpected way to long (5-s) coapplication of NMDA and glycine, the coagonist of NMDA receptors. Whereas the reversal potential of the peak NMDA current of this subset of neurons was still around 0 mV, the desensitizing current became outward at hyperpolarized potentials around Ϫ30 mV. A Cl Ϫ -free solution shifted the equilibrium potentials of the desensitized currents to around 0 mV. This outward current was not blocked by a Ca 2ϩ -free, Ba 2ϩ -containing solution, suggesting that the anionic conductance was not activated by Ca 2ϩ influx through NMDA receptor channels. Interestingly, glycine alone also evoked a current with a similar hyperpolarized reversal potential in this subset of neurons. The glycine current reversed around Ϫ50 mV, rectified outwardly, and inactivated strongly. Its desensitization was best fitted with a double exponential. Only the slow desensitization showed clear voltage dependence. The glycine current was not blocked by 200 M picrotoxin and 10 M zinc, was weakly antagonized by 1 M strychnine, and was not enhanced by 1 M zinc. In addition, 1 mM taurine, but not GABA, inactivated glycine currents, and 1 mM glycine occluded 10 mM taurine-mediated currents. These data indicate that a subset of nucleus accumbens neurons expresses glycine receptors and that either glycine or taurine could be an endogenous agonist for these receptors.The nucleus accumbens (NAcc), an interface region between limbic structures (hippocampus, amygdala, and prefrontal cortex) and the extrapyramidal motor system, modulates cognitive and motivational aspects of behavior that are translated into motor activity (Dunah et al., 1996). Projecting GABAergic neurons, also containing mostly either substance P or enkephalin, account for 90% of the neuronal population of NAcc (Meredith, 1999). These neurons receive massive dopaminergic input from the ventral tegmental area, glutamatergic input from cortical and subcortical regions, and GABA innervation from interneurons. The physiology of the receptors for these transmitters is relatively well known, because they have been heavily studied with regard to addiction to psychostimulants, opiates, and alcohol (Koob et al., 1998). NAcc-projecting neurons also receive inputs from acetylcholine-and somatostatin-containing interneurons (Groenewegen et al., 1991;Meredith, 1999), but relatively little is known about the physiology of receptors for these ligands in NAcc. Furthermore, some data suggest that other receptors, including glycine receptors, remain to be identified and characterized.Glycine receptors, along with GABA receptors, represent the primary fast inhibitory mechanisms in the central nervous system. Activation of glycine receptors opens anionic channels that hyperpolarize neurons. Until recently, it was generally believed that glycine receptors were almost exclusiv...

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Section: Resultsmentioning

confidence: 99%

“…2A). Because Ca 2ϩ -dependent Cl Ϫ channels are blocked by Ba 2ϩ (Scott et al, 1995), we substituted Ba 2ϩ for Ca 2ϩ . Surprisingly, Ba 2ϩ did not prevent the outward current (Fig.…”

Section: Resultsmentioning

confidence: 99%

Electrophysiological Evidence for Expression of Glycine Receptors in Freshly Isolated Neurons from Nucleus Accumbens

Martin

Siggins²

2002

The Journal of Pharmacology and Experimental Therapeutics

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“…These included calcium-activated potassium, sodium, chloride, and nonspecific cation (CAN) channels (for review, see Partridge et al 1994;Scott et al 1995;Vergara et al 1998). Increasing the intracellular chloride concentration via the recording pipette (pipette solution contained 75 mM K-gluconate and 60 mM KCl) had no effect on the amplitude or shape of the SADW (n ϭ 5, data not shown), indicating the current mediating the SADW was impermeable to chloride ions.…”

Section: Calcium-activated Cation Current Mediated the Sadwmentioning

confidence: 99%

Activation of a Calcium-Activated Cation Current During Epileptiform Discharges and Its Possible Role in Sustaining Seizure-Like Events in Neocortical Slices

Schiller

2004

Journal of Neurophysiology

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Schiller, Yitzhak. Activation of a calcium-activated cation current during epileptiform discharges and its possible role in sustaining seizure-like events in neocortical slices. J Neurophysiol 92: 862-872, 2004; 10.1152/jn.00972.2003. Epileptic seizures are composed of recurrent bursts of intense firing separated by periods of electrical quiescence. The mechanisms responsible for sustaining seizures and generating recurrent bursts are yet unclear. Using whole cell voltage recordings combined with intracellular calcium fluorescence imaging from bicuculline (BCC)-treated neocortical brain slices, I showed isolated paroxysmal depolarization shift (PDS) discharges were followed by a sustained afterdepolarization waveform (SADW) with an average peak amplitude of 3.3 Ϯ 0.9 mV and average half-width of 6.2 Ϯ 0.6 s. The SADW was mediated by the calcium-activated nonspecific cation current (I can ) as it had a reversal potential of -33.1 Ϯ 6.8 mV, was unaffected by changing the intracellular chloride concentrations, was markedly diminished by buffering [Ca 2ϩ ] i with intracellular bis-(o-aminophenoxy)-N,N,NЈ,NЈ-tetraacetic acid (BAPTA), and was reversibly abolished by the I can blocker flufenamic acid (FFA). The Ca 2ϩ influx responsible for activation of I can was mediated by both N-methyl-D-aspartate-receptor channels, voltagegated calcium channels and, to a lesser extent, internal calcium stores. In addition to isolated PDS discharges, BCC-treated brain slices also produced seizure-like events, which were accompanied by a prolonged depolarizing waveform underlying individual ictal bursts. The similarities between the initial part of this waveform and the SADW and the fact it was markedly reduced by buffering [Ca 2ϩ ] i with BAPTA strongly suggested it was mediated, at least in part, by I can . Addition of FFA reversibly eliminated recurrent bursting, and transformed seizure-like events into isolated PDS responses. These results indicated I can was activated during epileptiform discharges and probably participated in sustaining seizure-like events.

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“…larda, fare spinal ganglion nöronları, sıçan spinal ganglion nöronları, civciv spinal ganglion nöronları ve Klor kanalları hücre membranında ve organel parasempatik nöronlarda bildirilmiştir [3][4][5][6][7][8] . lerinde olmak üzere hemen hemen tüm hücre tiple rinde incelenmiştir.…”

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The Effect of Radio Frequency Signals on Calcium Dependent Chlorur Channels of Spinal Ganglial Cells

Erdoğan¹,

Ipekçioğlu²

2009

Kafkas Univ Vet Fak Derg

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Makale Kodu (Article Code): 2009/097-A ÖzetBu araştırma ile küresel mobil iletişim sistemlerinden (GSM: Global system for mobil communications) yayılan radyo frekans dalgalarının rat spinal ganglion sinir hücreleri hücre zarında bulunan kalsiyum bağımlı klor kanallarına etkisinin araştırılması amaçlanmıştır. Bu amaçla 20 adet 2 günlük Wistar sıçanlardan elde edilen ve kültür ortamında hazırlanan spinal ganglion sinir hücreleri kullanılmıştır. Hazırlanan çözelti içinde bulunan sinir hücreleri 5 santim mesafede 10 V/m elektrik alan şiddetinde 900 Mhz. frekansında toplam 6 dakika radyo frekansa maruz bırakıldı. Patch kenetleme tekniği ile hücre klor kanal akımlarında meydana gelen değişiklikler kaydedildi. Kayıtların analizinde ortama uygulanan radyo frekans sinyalinin, kalsiyum bağımlı klor kanallarının akımlarında ve membran potansiyelinde anlamlı değişimler oluşturmadığı gözlenmiştir.Anahtar sözcükler: Radyo frekans sinyali, Patch kenetleme tekniği, Spinal ganglion sinir hücresi The Effect of Radio Frequency Signals on Calcium Dependent Chlorur Channels of Spinal Ganglial Cells SummaryThis study is intended to predict the effect of radio frequency waves of global mobile communication systems (GSM: Global system for mobile communication systems) on the calcium dependent chlorur channels of rat dorsal root ganglia neural cell membranes. For this purpose the spinal ganglia cells from 20 Wistar rats which were 2 days old and those prepared in culture media were used. The nerve cells were radiated by 10V/m electric field strength at 900 Mhz. from a distance of 5 cm for six minutes. Changes in cell current were recorded by patch clamp techniques. In the analysis of the records the applied radio frequency signal was not found to change the currents of calcium dependent chlorur channels and the membrane potential meaningfully. The analysis of recordings does not show any meaningful change in the currents of calcium dependent chlorur channels and the membrane potential of the spinal ganglia cells after exposure to a 900 Mhz radiofrequency field.

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Aspects of calcium-activated chloride currents: A neuronal perspective

Cited by 68 publications

References 152 publications

Electrophysiological Evidence for Expression of Glycine Receptors in Freshly Isolated Neurons from Nucleus Accumbens

Electrophysiological Evidence for Expression of Glycine Receptors in Freshly Isolated Neurons from Nucleus Accumbens

Activation of a Calcium-Activated Cation Current During Epileptiform Discharges and Its Possible Role in Sustaining Seizure-Like Events in Neocortical Slices

The Effect of Radio Frequency Signals on Calcium Dependent Chlorur Channels of Spinal Ganglial Cells

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