Phorbol ester and dibutyryl cyclic AMP reduce content and efflux of taurine in primary cerebellar astrocytes in culture.
In 16-18 days in vitro (DIV) primary astrocyte cultures prepared from 7- to 9-day-old rats, 48 h exposure to 12,13-phorbol dibutyrate (PDBU) (1 microM) or dibutyryl cAMP (dbcAMP) (1 mM) reduced cellular taurine content, and both basal and 50 mM K+-evoked taurine efflux, but did not alter cellular glutamate or total protein content. Decreases in cellular taurine content first became apparent between 1 and 6 h and were maximal after 24 h. Treatment also rapidly altered astrocyte morphology to a more process-bearing form within 1 h. In contrast, fibroblast growth factor (FGF), epidermal growth factor (EGF), dbcGMP and alpha-PDBU did not affect cellular morphology, amino acid content or taurine efflux at any time tested. These findings suggest that, while protein kinase C translocation and adenylate cyclase activation may be only indirectly involved in the regulation of astrocyte morphology, long-term decreases in cellular taurine content and efflux may be the more direct result of these second messenger systems.
Philibert
R A
RA
Department of Pharmacology, College of Medicine, University of Iowa, Iowa City 52242.
Dutton
G R
GR
D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D003994:Bucladesine / Q000494:pharmacology*; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D013654:Taurine / Q000378:metabolism*
D013654:Taurine; D015240:Phorbol 12,13-Dibutyrate; D003994:Bucladesine; D011188:Potassium