Volume 17, Number 14,
Issue of July 15, 1997
pp. 5599-5609
Copyright ©1997 Society for Neuroscience
Neonatal Nonhandling and In Utero Prenatal Stress
Reduce the Density of NADPH-Diaphorase-Reactive Neurons in the Fascia
Dentata and Ammon's Horn of Rats
Received April 15, 1997; accepted April 29, 1997.
R. R. Vaid1,
B. K. Yee2,
U. Shalev3,
J. N. P. Rawlins2,
I. Weiner3,
J. Feldon3, and
S. Totterdell1
1 Department of Pharmacology, University of Oxford,
Oxford OX1 3QT, England, 2 Department of Experimental
Psychology, University of Oxford, Oxford OX1 3UD, England, and
3 Department of Psychology, Tel-Aviv University,
Ramat-Aviv, Tel-Aviv, Israel 69978
The density of nitric oxide (NO)-producing neurons in the fascia
dentata and Ammon's horn was assessed in 6-month-old male rats using
NADPH-diaphorase (NADPH-d) histochemistry. Two separate experiments
investigated whether (1) the complete absence of neonatal handling or
(2) the administration of periodic prenatal stress could affect the
expression and distribution of NADPH-d reactivity in the hippocampus,
when compared with rats raised in normal standard laboratory
conditions. Experiment 1 demonstrated that adult rats that received no
handling during neonatal development (from birth to postnatal day 22)
showed a very substantial reduction in NADPH-d-positive neurons per
unit area throughout the entire hippocampus when compared with rats
that received regular daily handling in this period. Quantitative
analysis further revealed that this effect was significantly more
pronounced in Ammon's horn than in the fascia dentata, and within
Ammon's horn the dorsal region was selectively more affected. Experiment 2 showed that prenatal stress, which involved the
administration of daily restraint stress to pregnant dams throughout
the gestation period, also led to a reduction in NADPH-d reactivity in
the hippocampus of the offspring of these dam when they reached
adulthood.
The present results suggest that behavioral manipulations in the early
neonatal or prenatal period can significantly alter the
neurodevelopment of the hippocampal NO system and these changes might
be related to some of the behavioral abnormalities that emerge later in
adulthood.
Key words:
nitric oxide;
NADPH-diaphorase;
hippocampus;
hypothalamo-pituitary-adrenal axis;
stress;
postnatal stimulation;
rat