Purine- and pyrimidine-stimulated phosphoinositide breakdown and intracellular calcium mobilisation in astrocytes

Pearce, B.R. and Langley, D.R. (1994) Purine- and pyrimidine-stimulated phosphoinositide breakdown and intracellular calcium mobilisation in astrocytes. Brain Research, 660 (2). pp. 329-332. 10.1016/0006-8993(94)91307-2.

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DOI: 10.1016/0006-8993(94)91307-2

Abstract

Phosphoinositide breakdown in cultured cortical astrocytes was assessed by measuring the accumulation of [3H]inositol phosphates (IP's) following incubations with various purines and pyrimidines. Dose-response relationships gave the following order of potency: 2-methylthioadenosine triphosphate (2-MeSATP) > uridine 5'-triphosphate (UTP) > ATP = ADP > inosine S' triphosphate (ITP). However, 2-MeSATP and UTP were only half as effective as either ATP or ADP in stimulating [3H]IP production. Astrocytes were also challenged with combined additions of maximally effective concentrations of agonists. Responses to ADP plus UTP and 2-MeSATP plus UTP were essentially additive whilst ATP plus UTP evoked a response which was only partially additive. ATP-stimulated [3H]IP accumulation was markedly reduced in the presence of 2-MeSATP suggesting that the latter may be a partial agonist at these receptors. We also examined the ability of ATP and UTP to increase intracellular Ca2+ concentrations in these cells. Greater than 90% of all cells tested responded to ATP with a release from internal Ca2+ stores but less than half of these responded similarly when challenged with UTP. Our results indicate that astrocytes possess both P(2Y)-purinoceptors and a population of receptors which are also coupled to phosphoinositide metabolism and intracellular Ca2+ mobilisation but recognise ATP and the pyrimidine nucleotide UTP.

Item Type:Article
Departments, units and centres:Department of Pharmacology > Department of Pharmacology
ID Code:3330
Journal or Publication Title:Brain Research
Deposited By:Library Staff
Deposited On:31 May 2012 17:28
Last Modified:31 May 2012 17:28

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