Perinatal exposure to morphine: reactive changes in the brain after 6-hydroxydopamine.
The effects of neonatal 6-hydroxydopamine treatment on the brain of control rats and of rats perinatally exposed to morphine were examined. Noradrenaline levels were increased in the pons-medulla, mesencephalon and caudate of 8-week-old control rats lesioned with neonatal 6-hydroxydopamine; perinatal morphine treatment prevented such an increase. In the caudate, there was a loss of dopamine and an increase of serotonin following the neurotoxic lesion; exposure to perinatal morphine prevented the serotonin increase. Brain expression of synapsin I mRNA was particularly abundant in cerebral cortex, hippocampus, dentate gyrus and olfactory bulb. In perinatal morphine-treated rats, the expression of synapsin I mRNA was significantly reduced; interestingly, the neonatal treatment with 6-hydroxydopamine normalized its expression. Therefore, brain-reactive neurochemical changes triggered by 6-hydroxydopamine were suppressed by perinatal morphine exposure whereas the association of morphine exposure and 6-hydroxydopamine lesion promoted the normal mRNA expression of the synaptic marker synapsin I.
Gorio
A
A
Department of Medical Pharmacology, University of Milano, Italy.
Vergani
L
L
Malosio
M L
ML
Lesma
E
E
Di Giulio
A M
AM
D018663:Adrenergic Agents / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D002421:Caudate Nucleus / Q000187:drug effects / Q000378:metabolism; D005260:Female; D008636:Mesencephalon / Q000187:drug effects / Q000378:metabolism; D009020:Morphine / Q000494:pharmacology*; D009638:Norepinephrine / Q000032:analysis*; D016627:Oxidopamine / Q000494:pharmacology*; D011149:Pons / Q000187:drug effects / Q000378:metabolism; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012333:RNA, Messenger; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000032:analysis; D016704:Synapsins / Q000032:analysis
D018663:Adrenergic Agents; D012333:RNA, Messenger; D016704:Synapsins; D012701:Serotonin; D009020:Morphine; D016627:Oxidopamine; D009638:Norepinephrine