DIFFERENTIAL EFFECT OF TAURINE AND SEROTONIN ON THE OUTGROWTH FROM EXPLANTS OR ISOLATED CELLS OF THE RETINA

The sulfur amino acid taurine and the indoleamine serotonin increases and decreases, respectively, the outgrowth from goldfish retinal expla nts. Taurine seems to be acting, at least partially, through an increa se in calcium fluxes, and the serotonin-inhibiting effect appears to b e mediated by serotonin,, receptors and cAMP. Isolated cells of postcr ush goldfish retina and of retina: from 5-day-old rats were cultured i n the presence of taurine or serotonin. In the goldfish, the classical morphology of postcrush ganglion cells was observed. An antibody agai nst the glycoprotein Thy-1 labelled three types of cells in the cultur es of goldfish retina. The number of cells outgrowing and the length o f the main neurite was measured at 5 days in culture in both species. The number of cells presenting neurites was increased in the goldfish retina by the addition of taurine, and decreased by serotonin. However , the length of the neurites was unaffected by the addition of the mod ulators. In the rat, only a slight decrease in the number of cells out growing was observed in the presence of serotonin. The incorporation o f [H-3]thymidine was not modified after 5 days in culture in the prese nce of taurine or serotonin, either in the goldfish or in the rat reti na. The antibody Thy 1.1 can label retinal cells of the goldfish in vi tro, one of them being ganglion cells. The trophic effect exerted by t aurine in the postcrush goldfish retina needs the integrity of the tis sue favoring the interaction of cells and factors, because outgrowth i ncreases in retinal explants, but not in isolated cells. (C) 1997 ISDN .