FENS Forum 2006

FENS Forum 2006 - Vienna

For lectures, symposia and workshops, time indicates the beginning of the session.
For posters, authors are expected to be in attendance at their posters at the time indicated.

First author: Burgos, Miguel (poster)

Poster board 267 - Mon 10/07, 12:15 - Hall Y
Session 084 - Calcium channels
Abstract A084.6, published in FENS Forum Abstracts, vol. 3, 2006.
Ref.: FENS Abstr., vol.3, A084.6, 2006

Author(s) Burgos M. (1), Pastor D. (2), Martinez-Galan J. R. (3), Fernandez-Vaquero C. (1), Benavides A. (2), Fradejas N. (2), Tranque P. (1) & Calvo S. (2)

Addresse(s) (1) Physiol. Fac. Medi. UCLM CRIB, Albacete, Spain; (2) Pharmacol. Fac. Medi. UCLM CRIB, Albacete, Spain; (3) Histol. Fac. Medi. UCLM CRIB, Albacete, Spain

Title Upregulation of astrocyte L-type calcium channels by PKCepsilon.

Text Changes in astrocyte intracellular Ca2+ levels are an important signal underlying neuron-glia cross-talking, and numerous other calcium-mediated glial-cell functions. The recent discovery indicating that cortical astrocytes express several types of voltage-gated calcium channels suggests that these channels may indeed play substantial roles in the regulation of astrocyte Ca2+ influx and, consequently, in calcium-mediated glial cell functions. However, the identification and characterization of voltage-gated calcium channels expressed by astrocytes remains unfinished.
Voltage-gated Ca2+ channels are prone to modulation by PKC. Indeed, PKC activation has been shown to either enhance or inhibit depolarization-evoked Ca2+ currents depending on the cell type. Interestingly, PKCepsilon has been shown to mediate the neuronal up-regulation of N-type channels after chronic ethanol exposure. On the other hand, activation of PKCepsilon has remarkable effects on astrocytes, which adopt a stellated morphology characteristic of a reactive phenotype.
This work describes the effects of PKCepsilon activation on mouse cortical astrocyte L-type channels. We have used an adenoviral vector to express either the wild-type or the constitutively-active form of PKCepsilon in primary cultures of astrocytes. The expression of the alpha1 subunit conforming the L-type channel was analyzed by quantitative PCR, western blotting and immunofluorescence. We found that the CaV1.2 subunit mRNA is strongly and specifically upregulated by PKCepsilon, and that a very significant increase in the CaV1.2 protein follows mRNA upregulation. Finally, immunofluorescence analysis revealed that calcium channel staining is preferentially confined to the stellation processes that PKCe induces in astrocytes, suggesting a role for these calcium channels in astrocyte activation.
Supported, in part, by grants PAI05-017 from JCCM to S. C. and CSAN02-0023 to P. T. Dolores Pastor has a Fellowship from JCCM.

Theme Synaptic transmission and excitability
Voltage-dependent ion channels / Calcium channels

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Author(s)	Burgos M. (1), Pastor D. (2), Martinez-Galan J. R. (3), Fernandez-Vaquero C. (1), Benavides A. (2), Fradejas N. (2), Tranque P. (1) & Calvo S. (2)
Addresse(s)	(1) Physiol. Fac. Medi. UCLM CRIB, Albacete, Spain; (2) Pharmacol. Fac. Medi. UCLM CRIB, Albacete, Spain; (3) Histol. Fac. Medi. UCLM CRIB, Albacete, Spain
Title	Upregulation of astrocyte L-type calcium channels by PKCepsilon.
Text	Changes in astrocyte intracellular Ca2+ levels are an important signal underlying neuron-glia cross-talking, and numerous other calcium-mediated glial-cell functions. The recent discovery indicating that cortical astrocytes express several types of voltage-gated calcium channels suggests that these channels may indeed play substantial roles in the regulation of astrocyte Ca2+ influx and, consequently, in calcium-mediated glial cell functions. However, the identification and characterization of voltage-gated calcium channels expressed by astrocytes remains unfinished. Voltage-gated Ca2+ channels are prone to modulation by PKC. Indeed, PKC activation has been shown to either enhance or inhibit depolarization-evoked Ca2+ currents depending on the cell type. Interestingly, PKCepsilon has been shown to mediate the neuronal up-regulation of N-type channels after chronic ethanol exposure. On the other hand, activation of PKCepsilon has remarkable effects on astrocytes, which adopt a stellated morphology characteristic of a reactive phenotype. This work describes the effects of PKCepsilon activation on mouse cortical astrocyte L-type channels. We have used an adenoviral vector to express either the wild-type or the constitutively-active form of PKCepsilon in primary cultures of astrocytes. The expression of the alpha1 subunit conforming the L-type channel was analyzed by quantitative PCR, western blotting and immunofluorescence. We found that the CaV1.2 subunit mRNA is strongly and specifically upregulated by PKCepsilon, and that a very significant increase in the CaV1.2 protein follows mRNA upregulation. Finally, immunofluorescence analysis revealed that calcium channel staining is preferentially confined to the stellation processes that PKCe induces in astrocytes, suggesting a role for these calcium channels in astrocyte activation. Supported, in part, by grants PAI05-017 from JCCM to S. C. and CSAN02-0023 to P. T. Dolores Pastor has a Fellowship from JCCM.
Theme	Synaptic transmission and excitability Voltage-dependent ion channels / Calcium channels