Abstract
Tetramethylenedisulfotetramine (TETS) is a potent convulsant that is considered a chemical threat agent. We characterized TETS as an activator of spontaneous Ca2+ oscillations and electrical burst discharges in mouse hippocampal neuronal cultures at 13-17 days in vitro using FLIPR Fluo-4 fluorescence measurements and extracellular microelectrode array recording. Acute exposure to TETS (≥ 2μM) reversibly altered the pattern of spontaneous neuronal discharges, producing clustered burst firing and an overall increase in discharge frequency. TETS also dramatically affected Ca2+ dynamics causing an immediate but transient elevation of neuronal intracellular Ca2+ followed by decreased frequency of Ca2+ oscillations but greater peak amplitude. The effect on Ca2+ dynamics was similar to that elicited by picrotoxin and bicuculline, supporting the view that TETS acts by inhibiting type A gamma-aminobutyric acid (GABAA) receptor function. The effect of TETS on Ca2+ dynamics requires activation of N-methyl-d-aspartic acid (NMDA) receptors, because the changes induced by TETS were prevented by MK-801 block of NMDA receptors, but not nifedipine block of L-type Ca2+ channels. Pretreatment with the GABAA receptor-positive modulators diazepam and allopregnanolone partially mitigated TETS-induced changes in Ca2+ dynamics. Moreover, low, minimally effective concentrations of diazepam (0.1μM) and allopregnanolone (0.1μM), when administered together, were highly effective in suppressing TETS-induced alterations in Ca2+ dynamics, suggesting that the combination of positive modulators of synaptic and extrasynaptic GABAA receptors may have therapeutic potential. These rapid throughput in vitro assays may assist in the identification of single agents or combinations that have utility in the treatment of TETS intoxication.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 362-372 |
| Number of pages | 11 |
| Journal | Toxicological Sciences |
| Volume | 130 |
| Issue number | 2 |
| DOIs | |
| State | Published - Dec 2012 |
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Keywords
- Ca
- GABA receptors
- Microelectrode array
- NMDA receptors
- Oscillations
- Rapid throughput assay
- Tetramethylenedisulfotetramine
ASJC Scopus subject areas
- Toxicology
Cite this
Tetramethylenedisulfotetramine alters Ca2+ dynamics in cultured hippocampal neurons : Mitigation by NMDA receptor blockade and GABAA receptor-positive modulation. / Cao, Zhengyu; Hammock, Bruce D.; Mccoy, Mark; Rogawski, Michael A; Lein, Pamela J; Pessah, Isaac N.
In: Toxicological Sciences, Vol. 130, No. 2, 12.2012, p. 362-372.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Tetramethylenedisulfotetramine alters Ca2+ dynamics in cultured hippocampal neurons
T2 - Mitigation by NMDA receptor blockade and GABAA receptor-positive modulation
AU - Cao, Zhengyu
AU - Hammock, Bruce D.
AU - Mccoy, Mark
AU - Rogawski, Michael A
AU - Lein, Pamela J
AU - Pessah, Isaac N
PY - 2012/12
Y1 - 2012/12
N2 - Tetramethylenedisulfotetramine (TETS) is a potent convulsant that is considered a chemical threat agent. We characterized TETS as an activator of spontaneous Ca2+ oscillations and electrical burst discharges in mouse hippocampal neuronal cultures at 13-17 days in vitro using FLIPR Fluo-4 fluorescence measurements and extracellular microelectrode array recording. Acute exposure to TETS (≥ 2μM) reversibly altered the pattern of spontaneous neuronal discharges, producing clustered burst firing and an overall increase in discharge frequency. TETS also dramatically affected Ca2+ dynamics causing an immediate but transient elevation of neuronal intracellular Ca2+ followed by decreased frequency of Ca2+ oscillations but greater peak amplitude. The effect on Ca2+ dynamics was similar to that elicited by picrotoxin and bicuculline, supporting the view that TETS acts by inhibiting type A gamma-aminobutyric acid (GABAA) receptor function. The effect of TETS on Ca2+ dynamics requires activation of N-methyl-d-aspartic acid (NMDA) receptors, because the changes induced by TETS were prevented by MK-801 block of NMDA receptors, but not nifedipine block of L-type Ca2+ channels. Pretreatment with the GABAA receptor-positive modulators diazepam and allopregnanolone partially mitigated TETS-induced changes in Ca2+ dynamics. Moreover, low, minimally effective concentrations of diazepam (0.1μM) and allopregnanolone (0.1μM), when administered together, were highly effective in suppressing TETS-induced alterations in Ca2+ dynamics, suggesting that the combination of positive modulators of synaptic and extrasynaptic GABAA receptors may have therapeutic potential. These rapid throughput in vitro assays may assist in the identification of single agents or combinations that have utility in the treatment of TETS intoxication.
AB - Tetramethylenedisulfotetramine (TETS) is a potent convulsant that is considered a chemical threat agent. We characterized TETS as an activator of spontaneous Ca2+ oscillations and electrical burst discharges in mouse hippocampal neuronal cultures at 13-17 days in vitro using FLIPR Fluo-4 fluorescence measurements and extracellular microelectrode array recording. Acute exposure to TETS (≥ 2μM) reversibly altered the pattern of spontaneous neuronal discharges, producing clustered burst firing and an overall increase in discharge frequency. TETS also dramatically affected Ca2+ dynamics causing an immediate but transient elevation of neuronal intracellular Ca2+ followed by decreased frequency of Ca2+ oscillations but greater peak amplitude. The effect on Ca2+ dynamics was similar to that elicited by picrotoxin and bicuculline, supporting the view that TETS acts by inhibiting type A gamma-aminobutyric acid (GABAA) receptor function. The effect of TETS on Ca2+ dynamics requires activation of N-methyl-d-aspartic acid (NMDA) receptors, because the changes induced by TETS were prevented by MK-801 block of NMDA receptors, but not nifedipine block of L-type Ca2+ channels. Pretreatment with the GABAA receptor-positive modulators diazepam and allopregnanolone partially mitigated TETS-induced changes in Ca2+ dynamics. Moreover, low, minimally effective concentrations of diazepam (0.1μM) and allopregnanolone (0.1μM), when administered together, were highly effective in suppressing TETS-induced alterations in Ca2+ dynamics, suggesting that the combination of positive modulators of synaptic and extrasynaptic GABAA receptors may have therapeutic potential. These rapid throughput in vitro assays may assist in the identification of single agents or combinations that have utility in the treatment of TETS intoxication.
KW - Ca
KW - GABA receptors
KW - Microelectrode array
KW - NMDA receptors
KW - Oscillations
KW - Rapid throughput assay
KW - Tetramethylenedisulfotetramine
UR - http://www.scopus.com/inward/record.url?scp=84869381354&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84869381354&partnerID=8YFLogxK
U2 - 10.1093/toxsci/kfs244
DO - 10.1093/toxsci/kfs244
M3 - Article
C2 - 22889812
AN - SCOPUS:84869381354
VL - 130
SP - 362
EP - 372
JO - Toxicological Sciences
JF - Toxicological Sciences
SN - 1096-6080
IS - 2
ER -