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  • Title: Type-1 and type-2 astrocytes are distinct targets for prostaglandins D2, E2, and F2 alpha.
    Author: Ito S, Sugama K, Inagaki N, Fukui H, Giles H, Wada H, Hayaishi O.
    Journal: Glia; 1992; 6(1):67-74. PubMed ID: 1324890.
    Abstract:
    Accumulating evidence has revealed that astrocytes are potential targets for various neurotransmitters. Here we investigated the effects of prostaglandins (PGs) on signal transduction in purified primary cultures of rat type-1 and type-2 astrocytes. PGF2 alpha, PGD2, and 9 alpha,11 beta-PGF2, a metabolite of PGD2 and a stereoisomer of PGF2 alpha, evoked a rapid rise in the intracellular Ca2+ concentration ([Ca2+]i) in type-1, but not in type-2, astrocytes. STA2, a stable analogue of thromboxane A2, was less effective, and PGE2 showed little effect. The PG-induced rise in [Ca2+]i was not blocked by an antagonist of either PGD2 receptor or thromboxane A2 receptor. PGF2 alpha and 9 alpha,11 beta-PGF2 stimulated rapid formation of inositol trisphosphate followed by inositol bisphosphate and inositol monophosphate. On the other hand, PGE2 increased the intracellular level of cyclic AMP in type-2 astrocytes, rather than in type-1 astrocytes. The potency of PGs for cyclic AMP formation was in the following order: PGE2 greater than PGE1 greater than or equal to STA2 much greater than iloprost, a stable analogue of PGI2. PGD2 and PGF2 alpha had no effect on cyclic AMP formation. These results demonstrate that type-1 astrocytes preferentially express PGF2 alpha receptors, the activation of which leads to phosphoinositide metabolism and [Ca2+]i elevation, whereas type-2 astrocytes possess PGE receptors that are linked to cyclic AMP formation.
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