Browsing by Author "Contreras, Jorge E."

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    Control of astrocytic Ca2+ signaling by nitric oxide-dependent S-nitrosylation of Ca2+ homeostasis modulator 1 channels
    (2024) Puebla Catalán, Mariela del Carmen; Muñoz Camus, Manuel Francisco; Lillo Gallardo, Mauricio Alejandro; Contreras, Jorge E.; Figueroa, Xavier
    Background Astrocytes Ca2+ signaling play a central role in the modulation of neuronal function. Activation of metabotropic glutamate receptors (mGluR) by glutamate released during an increase in synaptic activity triggers coordinated Ca2+ signals in astrocytes. Importantly, astrocytes express the Ca2+-dependent nitric oxide (NO)-synthetizing enzymes eNOS and nNOS, which might contribute to the Ca2+ signals by triggering Ca2+ influx or ATP release through the activation of connexin 43 (Cx43) hemichannels, pannexin-1 (Panx-1) channels or Ca2+ homeostasis modulator 1 (CALHM1) channels. Hence, we aim to evaluate the participation of NO in the astrocytic Ca2+ signaling initiated by stimulation of mGluR in primary cultures of astrocytes from rat brain cortex. Results: Astrocytes were stimulated with glutamate or t-ACPD and NO-dependent changes in [Ca2+]i and ATP release were evaluated. In addition, the activity of Cx43 hemichannels, Panx-1 channels and CALHM1 channels was also analyzed. The expression of Cx43, Panx-1 and CALHM1 in astrocytes was confirmed by immunofluorescence analysis and both glutamate and t-ACPD induced NO-mediated activation of CALHM1 channels via direct S-nitrosylation, which was further confirmed by assessing CALHM1-mediated current using the two-electrode voltage clamp technique in Xenopus oocytes. Pharmacological blockade or siRNA-mediated inhibition of CALHM1 expression revealed that the opening of these channels provides a pathway for ATP release and the subsequent purinergic receptor-dependent activation of Cx43 hemichannels and Panx-1 channels, which further contributes to the astrocytic Ca2+ signaling. Conclusions Our findings demonstrate that activation of CALHM1 channels through NO-mediated S-nitrosylation in astrocytes in vitro is critical for the generation of glutamate-initiated astrocytic Ca2+ signaling.
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    Growth and condition of larval rockfish in a Patagonian fjord-type inlet : role of hydrographic conditions and food availability
    (2015) Landaeta, Mauricio F.; Contreras, Jorge E.; Bustos, Claudia A.; Pérez Matus, Alejandro A.
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    Remembrances of Dr. Michael VL Bennett by Iberoamerican Colleagues and Friends
    (2024) Abudara, Verónica; Araneda, Ricardo C.; Barrio, Luis; Berthoud, Viviana M.; Contreras, Jorge E.; Eugenin, Eliseo; Lerma, Juan; Orellana Roca, Juan Andrés; Palacios Prado, Nicolás; Perez-Armendariz, Elia Martha; Retamal, Mauricio A.; Saez, Juan C.
    On behalf of the Iberoamerican scientific community in the gap junction field, we offer a tribute to the late Dr. Michael V.L. Bennett, who passed away on November 16, 2023