Ethanol regulates calcium channels in clonal neural cells.

Messing, Robert O.; Carpenter, Celia L.; Diamond, Ivan; Greenberg, David A.

doi:10.1073/pnas.83.16.6213

Cited by 163 publications

(66 citation statements)

References 16 publications

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“…1 A and B). This is similar to the increase we observed previously with another PC12 cell line (8), except that a maximal response was achieved at 6 days in those cells instead of at 5 days as observed in the current cell line. To examine whether the increase in K ϩ -stimulated 45 Ca 2ϩ uptake was PKC-dependent, we cultured cells in the presence of 1 M GF 109203X, which is a relatively selective PKC inhibitor that inhibits all phorbol ester-sensitive PKC isozymes except PKC (37,38).…”

Section: Methodssupporting

confidence: 77%

“…Cells were grown at 37°C in plastic tissue culture flasks in Dulbecco's modified Eagle's medium supplemented with 5% fetal calf serum, 10% horse serum, 50 units/ml penicillin, 50 g/ml streptomycin, and 2 mM glutamine in a humidified atmosphere of 90% air and 10% CO 2 . Cells were cultured with ethanol in tightly capped tissue culture flasks or in six-well plates wrapped in Parafilm, and the medium was changed daily as described previously (8,29). Parallel control samples were cultured in a similar manner without ethanol.…”

Section: Methodsmentioning

confidence: 99%

“…In PC12 cells, prolonged exposure to 25-200 mM ethanol for 2-6 days produces a reversible concentration-and time-dependent increase in K ϩ -evoked 45 Ca 2ϩ uptake (8,9,14) and L-type calcium currents (14) measured in the absence of ethanol. This is associated with a corresponding increase in the number of binding sites for dihydropyridine Ca 2ϩ channel antagonists (8,9), suggesting that cells adapt to chronic ethanol exposure by increasing expression of functional L-type calcium channels. Similar increases in dihydropyridine binding have been detected in ethanol-treated NG108-15 neuroblastoma ϫ glioma cells (15) and in brain membranes from ethanol-treated rats (16).…”

mentioning

confidence: 99%

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Protein Kinase Cδ Mediates Ethanol-induced Up-regulation of L-type Calcium Channels

Gerstin

McMahon

Dadgar

et al. 1998

Journal of Biological Chemistry

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Brief ethanol exposure inhibits L-type, voltage-gated calcium channels in neural cells, whereas chronic exposure increases the number of functional channels. In PC12 cells, this adaptive response is mediated by protein kinase C (PKC), but the PKC isozyme responsible is unknown. Since chronic ethanol exposure increases expression of PKC␦ and PKC⑀, we investigated the role these isozymes play in up-regulation of L-type channels by ethanol. Incubation with the PKC inhibitor GF 109203X or expression of a PKC␦ fragment that inhibits phorbol ester-induced PKC␦ translocation largely prevented ethanol-induced increases in dihydropyridine binding and K ؉ -stimulated 45 Ca 2؉ uptake. A corresponding PKC⑀ fragment had no effect on this response. These findings indicate that PKC␦ mediates up-regulation of L-type channels by ethanol. Remaining responses to ethanol in cells expressing the PKC␦ fragment were not inhibited by GF 109203X, indicating that PKC␦-independent mechanisms also contribute. PKC␦ overexpression increased binding sites for dihydropyridine and L-channel antagonists, but did not increase K ؉ -stimulated 45 Ca 2؉ uptake, possibly because of homeostatic responses that maintain base-line levels of channel function. Since L-type channels modulate drinking behavior and contribute to neuronal hyperexcitability during alcohol withdrawal, these findings suggest an important role for PKC␦ in alcohol consumption and dependence.Understanding biochemical mechanisms that underlie alcohol tolerance and dependence may lead to new treatments for alcoholism. In nonalcoholic persons, intoxication develops at blood alcohol levels of 10 -35 mM, and acute tolerance develops rapidly, so that after a few hours, an individual can appear sober at alcohol levels that previously caused intoxication (1). The mechanism for acute tolerance may involve activation of Fyn kinase and reduced sensitivity of tyrosine-phosphorylated N-methyl-D-aspartate receptors to inhibition by alcohol (2). Chronic tolerance is characteristic of alcoholism, and its magnitude in alcoholics can be quite striking. For example, blood alcohol concentrations above 100 mM produce coma in a nonalcoholic person, whereas human alcoholics may appear sober or only mildly intoxicated with blood levels of 100 -150 mM (3, 4).The ability of ethanol to alter the function of neuronal voltagedependent calcium channels appears to contribute to chronic tolerance. In several neural preparations, ethanol inhibits voltage-dependent calcium influx and calcium currents (5-13).Chronic exposure results in the development of tolerance to the inhibitory actions of ethanol on calcium channels (6, 7). The mechanisms underlying this adaptive response have been studied most in the neural cell line PC12. In PC12 cells, prolonged exposure to 25-200 mM ethanol for 2-6 days produces a reversible concentration-and time-dependent increase in K ϩ -evoked 45 Ca 2ϩ uptake (8, 9, 14) and L-type calcium currents (14) measured in the absence of ethanol. This is associated with a corresponding increase in...

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Section: Methodssupporting

confidence: 77%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Protein Kinase Cδ Mediates Ethanol-induced Up-regulation of L-type Calcium Channels

Gerstin

McMahon

Dadgar

et al. 1998

Journal of Biological Chemistry

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“…Their work suggests that acamprosate acts as a 'partial coagonist' at the NMDA receptor, such that low concentrations enhance activation when receptor activity is low, and high concentrations inhibit activation when receptor activity is high. This may be particularly relevant to the success of acamprosate as a pharmacotherapy given that chronic exposure to ethanol results in an upregulation of NMDA receptors (Grant, 1990;Liljequist, 1991;Hoffman and Tabakoff, 1994) and an upregulation in the density of voltage-dependent calcium channels (Messing et al, 1986;Dolin et al, 1987;Dolin and Little, 1989;Whittington and Little, 1991). Acamprosate also promotes the release of taurine in the brain (Dahchour and de Witte, 2000).…”

Section: Introductionmentioning

confidence: 99%

Effects of Naltrexone Alone and In Combination With Acamprosate on the Alcohol Deprivation Effect in Rats

Heyser

Moc

Koob

2003

Neuropsychopharmacol

101

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Previous research in our laboratory has shown that responding for ethanol increases after a period of imposed deprivation during which no ethanol is available (the alcohol deprivation effect). This selective increase in responding for ethanol was blocked by chronic administration of acamprosate. In the present study the effects of naltrexone and the combination of naltrexone+acamprosate on oral ethanol self-administration were examined following an imposed period of abstinence. Male Wistar rats were trained to respond for ethanol (10% w/v) or water in a two-lever free-choice condition. After training, separate groups of rats received chronic injections (2 Â /day) of saline, naltrexone, or naltrexone+acamprosate during a 5-day period of abstinence. Ethanol self-administration was tested in all groups of rats on the last day of abstinence, 30 min after the last drug injection. Responding for ethanol increased significantly following the deprivation period in animals treated with saline. Chronic administration of naltrexone and the combination naltrexone+acamprosate blocked the increased ethanol consumption following the imposed abstinence period on post-deprivation Day 1. On post-deprivation Day 2, the combination of acamprosate with naltrexone blocked the rebound increase in ethanol consumption observed in animals treated with a low dose of naltrexone. These results support the hypothesis that naltrexone and acamprosate are effective in modulating aspects of alcohol-seeking behavior, and under certain situations may be more effective in combination.

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“…It is thought that these effects may have relevance to the pathophysiological changes that occur in alcoholism (Charness et al, 1989). For example, ethanol acutely inhibits Ca2+ uptake and voltage-sensitive Ca2' currents in neuronal cells, whereas chronic ethanol enhances these parameters (Messing et al, 1986;Grant et al, 1993). The NG108-15 mouse neuroblastoma x rat glioma hybrid cell line has been widely used as a model of neuronal function.…”

Section: Introductionmentioning

confidence: 99%

Effects of acute and chronic ethanol on cyclic AMP accumulation in NG108‐15 cells: differential dependence of changes on extracellular adenosine

Kelly

Harrison

Williams³

1995

British J Pharmacology

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1 This study investigated the effects of acute and chronic ethanol on basal, agonist-and forskolinstimulated cyclic AMP formation in NG108-15 mouse neuroblastoma x rat glioma hybrid cells, and examined the role of changes in extracellular adenosine concentrations on the effects observed. 2 NG108-15 cells incubated acutely with ethanol (1-200 mM) displayed concentration-dependent increases in basal and iloprost-stimulated (300nM; a prostanoid IP receptor agonist) cyclic AMP accumulation but a concentration-dependent decrease in forskolin-stimulated (10LM) accumulation. 3 Cells treated chronically with ethanol (200 mM) for 48 h displayed increases over control in basal, iloprost-(0.001-10 LM) and forskolin (0.01-100 gM)-stimulated cyclic AMP formation. However, chronic ethanol did not affect [3H]-iloprost binding to cell membranes. 4 Inclusion of adenosine deaminase (ADA; 1 unit ml-1) during the incubation period to measure cyclic AMP accumulation completely abolished the increase in basal accumulation following chronic ethanol, but did not affect the increase in iloprost stimulation. On the other hand ADA partially reversed the increase in forskolin stimulation following chronic ethanol, but even in the presence of high concentrations of ADA (5 units ml-') the forskolin stimulation remained elevated above control. 5 Cells treated chronically with the adenosine receptor agonist 5'-(N-ethylcarboxamido)-adenosine (NECA; 10 tLM for 48 h) displayed a reduction in subsequent NECA-and forskolin-stimulated cyclic AMP accumulation, but iloprost stimulation was not affected. ADA included acutely during the incubation period to measure cyclic AMP accumulation abolished the reduction in forskolin but not NECA stimulation produced by the chronic NECA pretreatment. 6 We have previously noted that ethanol inhibits NG108-15 cell proliferation and alters cell morphology. To mimic this, cells were incubated in the absence of foetal calf serum for 48 h. Following this time, basal, iloprost-and forskolin-stimulated cyclic AMP formation was enhanced over that in cells grown in the presence of serum. 7 These results indicate that chronic ethanol enhances cyclic AMP formation in intact NG108-15 cells by more than one mechanism: one involves increased extracellular adenosine concentrations and the other a change in the transduction system beyond the receptor, possibly involving the adenylyl cyclase enzyme. Furthermore the ethanol-induced changes in cyclic AMP accumulation may relate to alterations in NG108-15 cell growth and development.

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Ethanol regulates calcium channels in clonal neural cells.

Cited by 163 publications

References 16 publications

Protein Kinase Cδ Mediates Ethanol-induced Up-regulation of L-type Calcium Channels

Protein Kinase Cδ Mediates Ethanol-induced Up-regulation of L-type Calcium Channels

Effects of Naltrexone Alone and In Combination With Acamprosate on the Alcohol Deprivation Effect in Rats

Effects of acute and chronic ethanol on cyclic AMP accumulation in NG108‐15 cells: differential dependence of changes on extracellular adenosine

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