Effects of NO-Synthase Inhibitors on Development of Sea Urchin Embryos

Effects of NO-synthase inhibitors N-nitro-L-arginine (L-NA) and its methylated ether (L-NAME) on embryonic development of sea urchins Paracentrotus lividus and Arbacia lixula were studied from the time of fertilization to the stage of transition to active nutrition (stage of the later pluteus 2). It has been shown that L-NAME (but not D-NAME) and L-NA (0.01–0.02 mM) produce a dose-dependent inhibition of growth of arms and apex of pluteus larvae, while differentiation of the intestine, coelom, pigment cells, and ciliated epithelium occurs without observable disturbances. A period of sensitivity to NO-synthase inhibitors was revealed; it coincided with the beginning of intensive spiculogenesis leading to elongation of arms and apex of the pluteus larva of the stage (prism 2—early pluteus 2). It is suggested that interaction of ectodermal cells with the primary mesenchime cells and extracellular matrix in morphogenetic processes providing formation of arms and apex of the pluteus larva can be modulated by NO in ontogenesis of sea urchins P. lividus and A. lixula.