Int. J. Dev. Biol. 43: 179 - 182 (1999)

Vol 43, Issue 2

Action of serotonin antagonists on cytoplasmic calcium levels in early embryos of sea urchin Lytechinus pictus

Published: 1 March 1999

Y B Shmukler, G A Buznikov and M J Whitaker

N.K.Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow. ybshm@ibrran.msk.su

Abstract

Possible interaction of the serotonergic system with intracellular calcium mechanisms was investigated using techniques of ratio imaging measurement of intracellular Ca2+ and confocal microscopy in cleaving embryos of sea urchin Lytechinus pictus. Some serotonin antagonists specifically increase free intracellular Ca2+ and evoke transient regression of the first cleavage furrow, suggesting possible linkage of serotonergic and calcium mechanisms in the regulation of cellular events during cleavage divisions. These effects were more pronounced in the experiments with hydrophilic 5-HT-antagonists, quarternary ammonium salts that do not penetrate the cell membrane. Thus, it appears that 5-HT-receptors which mediate these effects are localised on the cell membrane, whereas previously studied receptors mediating the cytostatic action of lipophilic 5-HT-antagonists are localised intracellularly.