+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Ammonium increases Ca(2+) signalling and upregulates expression of Cav1.2 gene in astrocytes in primary cultures and in the in vivo brain



Ammonium increases Ca(2+) signalling and upregulates expression of Cav1.2 gene in astrocytes in primary cultures and in the in vivo brain



Acta Physiologica 214(2): 261-274



The primary aim of this study was to identify the effects of hyperammonaemia on functional expression of Cav1.2 L-type Ca(2+) channels in astroglia. Primary cultures of mouse astrocytes were used to study effects of chronic treatment (1-5 days) with ammonium chloride, at 1, 3 and 5 mm on depolarization-induced increases in free cytosolic Ca(2+) concentration ([Ca(2+)]i , measured with Fura-2 based microfluorimetry) in control conditions and following treatment with the L-type Ca(2+) channel inhibitor, nifedipine, or with ryanodine receptor inhibitor, ryanodine. Expression of Cav1.2 mRNA was identified with RT-PCR, whereas protein content was determined by Western blotting. Sustained hyperammonaemia in vivo was induced by daily injections of urease (33 units kg body weight(-1), i.p.) for 3 days. Depolarization-induced [Ca(2+)]i transients sensitive to nifedipine (peak of the response) and to ryanodine (plateau phase) were significantly increased in astrocytes chronically exposed to ammonium. The ammonium-induced increase in Ca(2+) influx in astrocytes resulted from an upregulation of Cav1.2 channel's expression detected at mRNA and protein levels. Increase in Cav1.2 expression was prevented by ouabain antagonist canrenone. Similar upregulation of Cav1.2 gene expression was found in the brains of adult mice subjected to intraperitoneal injection of urease. In transgenic mice tagged with an astrocyte-specific or neurone-specific markers and treated with intraperitoneal injections of urease, the fluorescence-activated cell sorting of neurones and astrocytes demonstrated that Cav1.2 mRNA expression was upregulated in astrocytes, but not in neurones. Ammonium-induced deregulation of astroglial Ca(2+) signalling, is, in part, associated with upregulation of Cav1.2 L-type calcium channels.

Please choose payment method:






(PDF emailed within 0-6 h: $19.90)

Accession: 057168346

Download citation: RISBibTeXText

PMID: 25846713

DOI: 10.1111/apha.12500


Related references

Ammonium increases Ca(2+) signalling and up-regulates expression of TRPC1 gene in astrocytes in primary cultures and in the in vivo brain. Neurochemical Research 39(11): 2127-2135, 2015

Chronic fluoxetine administration increases expression of the L-channel gene Cav1.2 in astrocytes from the brain of treated mice and in culture and augments K(+)-induced increase in [Ca(2+)]i. Cell Calcium 55(3): 166-174, 2014

Valproate increases glutaminase activity in primary cultures of rat brain astrocytes. Journal of Neurochemistry 61(SUPPL ): S46, 1993

Protopanaxatriol Ginsenoside Rh1 Upregulates Phase II Antioxidant Enzyme Gene Expression in Rat Primary Astrocytes: Involvement of MAP Kinases and Nrf2/ARE Signaling. Biomolecules & Therapeutics 24(1): 33-39, 2016

Astrocyte Cultures Mimicking Brain Astrocytes in Gene Expression, Signaling, Metabolism and K + Uptake and Showing Astrocytic Gene Expression Overlooked by Immunohistochemistry and In Situ Hybridization. Neurochemical Research (): -, 2016

Glucocorticoid upregulates Na,K-ATPase gene expression in primary cultures of renal proximal tubule cells. FASEB Journal 8(4-5): A299, 1994

Okadaic acid increases nerve growth factor secretion, mRNA stability, and gene transcription in primary cultures of cortical astrocytes. Journal of Biological Chemistry 270(11): 5994-5999, 1995

Effects of alcohol on immediate-early gene expression in primary cultures of rat cortical astrocytes. Alcoholism Clinical & Experimental Research 23(3): 446-455, March, 1999

Truncation of murine CaV1.2 at Asp 1904 increases CaV1.3 expression in embryonic atrial cardiomyocytes. Pflugers Archiv 465(7): 955-964, 2014

Ethanol inhibits gene expression of nerve growth factor in primary cultures of rat astrocytes. Zhongguo Yaolixue Yu Dulixue Zazhi 14(2): 140-143, April, 2000

Arctigenin Increases Hemeoxygenase-1 Gene Expression by Modulating PI3K/AKT Signaling Pathway in Rat Primary Astrocytes. Biomolecules & Therapeutics 22(6): 497-502, 2014

Ceramide elevates 12-hydroxyeicosatetraenoic acid levels and upregulates 12-lipoxygenase in rat primary hippocampal cell cultures containing predominantly astrocytes. Neurochemistry International 53(6-8): 220-229, 2008

DHA upregulates FADS2 expression in primary cortical astrocytes exposed to vitamin A. Physiological Research, 2018

Infection with a chimeric adenovirus construct mediates high gene expression in primary cultures of neurones and astrocytes. Journal of Neurochemistry 65(SUPPL ): S78, 1995

Elevation of glutathione levels by ammonium ions in primary cultures of rat astrocytes. Neurochemistry International 37(2-3): 255-268, Aug -Sept, 2000