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0007-4888/07/14330372 © 2007 Springer Science+Business Media, Inc.
MORPHOLOGY AND PATHOMORPHOLOGY
Serotonin Is Involved in the Regulation of Histogenetic
Processes in Rat Embryonic Neocortex
E. S. Petrova and V. A. Otellin
Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 143, No. 3, pp. 344-348, March, 2007
Original article submitted July 13, 2006
We compared the dynamics of the development of ectopic transplants of embryonic (day
14) primordial neocortex from rats injected with serotonin inhibitor (para-chlorophenyl-
alanine; 400 mg/kg) on day 11 of pregnancy and transplants of similar primordial neo-
cortex incubated before transplantation in a medium with serotonin (3 µg/ml). The study
of mitotic activity and differentiation of transplanted cells showed that serotonin pro-
moted survival of the transplanted neuroepithelial cells and their differentiation into
nerve cells, and is involved in the regulation of their proliferation. We hypothesized that
serotonin accelerated the cell cycle of transplanted cells, thus accelerating the neuron
differentiation.
Key Words: serotonin; para-chlorophenylalanine; histogenesis; neocortex
Department of Morphology, Institute of Experimental Medicine,
Russian Academy of Medical Sciences, St. Petersburg
Study of the consequencies of prenatal injuries to
the brain in mammals under conditions of unfavor-
able environment is an important problem [2,4].
Study of the mechanisms regulating histogenetic
processes in the developing brain and their dis-
orders caused by various factors will help to detect
the causes of pathological states of the brain. Vari-
ous models are used for the study of delayed ef-
fects of disorders in the CNS precursor cell prolife-
ration, migration, and differentiation. Models of
prenatal serotonin (5-HT) depletion induced by para-
chlorophenylalanine (pCPA) [9] and ectopic neuro-
transplantation of rat embryonic primordial brain
cells into the nerve [8] are developed at Department
of Morphology of Institute of Experimental Medi-
cine. The model of prenatal 5-HT depletion is used
for investigating the neocortical histogenesis under
conditions of deficiency of 5-HT synthesis (5-HT
is a multifunctional compound acting as a neuro-
transmitter, hormone, and morphogene at different
stages of ontogeny) [1]. Isolation of the embryonic
primordium during certain periods of development,
incubation of primordial cells in a medium with
5-HT, and transplantation help to evaluate the histo-
genesis of embryonic neocortex after exposure to
pCPA and 5-HT. The cells were transplanted into
adult rat peripheral nerve. Ectopic transplantation
of embryonic primordial cells of the CNS as a me-
thod of in vivo culturing is a convenient model for
the study of the early histogenetic processes in
transplanted primordial cells [8].
We studied the impact of 5-HT for the division
and differentiation of the embryonic neocortical cells
developing after transplantation in adult rat nerve.
MATERIALS AND METHODS
The study was carried out on 35 Wistar rats (200-
250 g). Females were intraperitoneally injected with
pCPA (Acros organics) in a dose of 400 mg/kg on
day 11 of pregnancy [9]. Fragments of the dorso-
lateral wall of the anterior cerebral vesicle contai-
ning primordial neocortex were isolated from 14-day
Bulletin of Experimental Biology and Medicine, Vol. 143, No. 3,
March
, 2007