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Long‐term effects of neonatal handling on mu‐opioid receptor levels in the brain of the offspring
Author(s) -
Kiosterakis Georgios,
Stamatakis Antonios,
Diamantopoulou Anastasia,
Fameli Maria,
Stylianopoulou Fotini
Publication year - 2009
Publication title -
developmental psychobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 93
eISSN - 1098-2302
pISSN - 0012-1630
DOI - 10.1002/dev.20383
Subject(s) - ventral tegmental area , nucleus accumbens , offspring , opioid , psychology , endocrinology , hippocampal formation , medicine , anxiety , receptor , brain stimulation reward , prefrontal cortex , neuroscience , basolateral amygdala , emotionality , amygdala , dopamine , biology , dopaminergic , pregnancy , psychiatry , genetics , cognition
Neonatal handling is an experimental paradigm of an early experience which permanently alters hypothalamic–pituitary–adrenal axis function resulting in increased ability to cope with stress, and decreased emotionality. In the present work we investigated the effect of neonatal handling on adult rat brain mu‐opioid receptor levels, since the opioid system is known to play an important role in emotional processing, anxiety and stress responses. Neonatal handling resulted in increased levels of mu‐opioid receptors in the basolateral and central amygdaloid nuclei, in the CA3 and CA4 hippocampal areas, in the ventral tegmental area, the nucleus accumbens and the prefrontal cortex. Handled animals of both sexes had lower anxiety as measured in the elevated plus maze. The increased mu receptor levels could participate in the molecular mechanisms underlying the well‐documented decreased stress and anxiety responses of handled animals. © 2009 Wiley Periodicals, Inc. Dev Psychobiol 51: 439–449, 2009.