SEX DIMORPHIC ALTERATIONS IN POSTNATAL BRAIN CATECHOLAMINES AFTER GESTATIONAL MORPHINE

The concentration of brain catecholamines was measured in the hypothal amus, preoptic area (POA), frontal cortex, cerebellum, and striatum of rats exposed in utero to morphine (5-10 mg/kg/twice daily) during ges tation days 11-18. Prenatal morphine induced regionally specific, sexu ally dimorphic alterations in male and female norepinephrine (NE), and dopamine (DA) content at different postnatal ages. Prenatal morphine significantly increased NE content in the hypothalamus of both sexes a t postnatal day (PND) 23. In the POA, on the other hand, morphine incr eased NE content in exposed males at PND 23 and in females at PND 33. In the cerebellum, the NE content of both sexes was significantly elev ated at PND 45. In the striatum, NE content was increased by the prena tal morphine only in females at PND 16. The concentration of DA was al so affected in a sexually dimorphic manner. At PND 16, prenatal morphi ne increased the levels of hypothalamic DA only in males, and it reduc ed the content of DA in female but not male POA. At PND 45, prenatal m orphine increased DA in the hypothalamus of females and decreased it i n males. In the cerebellum of 16-day-old morphine-exposed animals, DA levels were increased only in males; at PND 45, the levels of DA were still increased in males but had not changed in females. In the striat um, the DA content was reduced only in males at PND 16. Thus, prenatal morphine alters the development of both NE and DA neurotransmitter sy stems in the hypothalamus, POA, striatum, and cerebellum in a sexually dimorphic manner.