Long-term effects of neonatal handling on mu-opioid receptor levels in the brain of the offspring.
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.
Kiosterakis
Georgios
G
Biology-Biochemistry Lab, Department of Basic Sciences, Faculty of Nursing, University of Athens, 123 Papadiamantopoulou str., 11527 Athens, Greece.
Stamatakis
Antonios
A
Diamantopoulou
Anastasia
A
Fameli
Maria
M
Stylianopoulou
Fotini
F
D000339:Affect; D000367:Age Factors; D000679:Amygdala / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000378:metabolism*; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism*; D008297:Male; D008562:Membrane Glycoproteins; D009714:Nucleus Accumbens / Q000378:metabolism; D010913:Pituitary-Adrenal System / Q000378:metabolism*; D017397:Prefrontal Cortex / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D017472:Receptors, Interleukin-1; D017450:Receptors, Opioid, mu / Q000378:metabolism*; D013315:Stress, Psychological / Q000378:metabolism*; D013997:Time Factors
D008562:Membrane Glycoproteins; D017472:Receptors, Interleukin-1; D017450:Receptors, Opioid, mu; C434984:TIRAP protein, human