TRANSMITTERS IN THE EMBRYOGENESIS OF XENOPUS LAEVIS
Nikishin D.A.(1), Kremnyov S.V.(2), Kudrin V.S. (3), Shmukler Yu.B.(1)
(1) N.K.Koltzov Institute of Developmental Biology Russian Academy of Sciences, Moscow, Group of Embryophysiology
(2) M.V.Lomonosov Moscow State University, Moscow, Department of Embryology
(3) V.V.Zakusov Institute of Pharmacology, Russian Academy of Medical Sciences, Moscow, Lab of Neurochemical Pharmacology
The presence of monoamine transmitter substances in embryogenesis of clawed frog X.laevis was investigated by HPLC. It was shown that serotonin, dopamine and noradrenaline are present in cells of embryos and larvae. During cleavage divisions the levels of serotonin was 2 ± 0,4 х 10-15 mol/embryo and then increased significantly at neurula and hatching stages (20 - 100 fold). Preincubation of the embryos with 100 microM 5-hydroxytryptophan during cleavage divisions evoked about tenfold increase of serotonin levels. Noradrenaline was present in the concentration of 439 ± 7 х 10-15 mol/embryo during cleavage divisions and then decreased to hatching stage in contrast to serotonin. Dopamine levels remained more or less constant during embryonic development (5 ± 0,6 х 10-15 mol/embryo). It is noteworthy that the levels of the transmitters could differ greatly in embryos from different females.
Thus, three transmitters were present in the cells of X.laevis embryos simultaneously, although the list of functionally active embryonic transmitters may not be limited by them. At least as concerns serotonin, the data obtained evidences in favor of the activity of system of serotonin synthesis (aromatic aminoacids decarboxylase) already during embryonic stages.
