Carnosine and beta-alanine release is stimulated by glutamatergic receptors in cultured rat oligodendrocytes.
Oligodendrocytes obtained from rat brain 0-2 A progenitor cells and differentiated in culture take up beta-alanine and synthesize carnosine (beta-Ala-His). The present study was designed to determine whether carnosine and beta-alanine are released from such cultures in response to some stimuli. An evoked release of these substances was not observed when the cells were incubated with 1 mM glutamate or 0.3 mM kainate. Addition of 0.1 mM cyclothiazide (CTZ) to the corresponding stimulus was accompanied by a distinct peak of release consisting of both carnosine and beta-alanine. The efflux was blocked completely in the case of kainate and to 80% in the case of glutamate when 50 microM 6,7-dinitroquinoxaline-2,3 (1H,4H)-dion (DNQX) was added to the cells at the same time as the receptor agonist. An increase of the efflux was observed in the presence of Zn2+. This effect was concentration-dependent. Total substitution of NaCl in the efflux medium by LiCl caused only a partial reduction of the release. GABA or 55 mM KCl showed only negligible effect. A large release of carnosine and beta-alanine was observed when oligodendrocyte cultures were treated with Ca2+ ionophore A 23187. These results suggest that oligodendrocytes exhibit a glutamate receptor-mediated release of carnosine and beta-alanine. The release is dependent on elevated intracellular Ca2+ concentration.
Max-Planck-Institut für experimentelle Endokrinologie, Hannover, Germany.
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Bakardjiev
D000818:Animals; D000831:Animals, Newborn; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000502:physiology; D002336:Carnosine / Q000096:biosynthesis / Q000378:metabolism*; D002478:Cells, Cultured; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology; D007608:Kainic Acid / Q000494:pharmacology; D009532:Nickel / Q000494:pharmacology; D009836:Oligodendroglia / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017470:Receptors, Glutamate / Q000502:physiology*; D015032:Zinc / Q000494:pharmacology; D015091:beta-Alanine / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D018690:Excitatory Amino Acid Agonists; D007476:Ionophores; D017470:Receptors, Glutamate; D015091:beta-Alanine; D000001:Calcimycin; D005680:gamma-Aminobutyric Acid; D009532:Nickel; D002336:Carnosine; D015032:Zinc; D011188:Potassium; D007608:Kainic Acid; D002118:Calcium