Behavioral and neuroanatomical sequelae of prenatal naloxone administration in the rat.
Pregnant Long-Evans hooded rats were dosed subcutaneously with 1 or 5 mg/kg/day naloxone hydrochloride, or an equal volume of vehicle, from gestational Day 4 (GD4) through GD19. Offspring were assessed for development of righting reflex, negative geotaxis, and open field activity, and for acquisition of a Warden maze; offspring sacrificed at postnatal Day (PND) 21 were assessed for several parameters of cerebellar, hippocampal, and motor cortical morphology. Five mg/kg/day naloxone accelerated development of negative geotaxis and righting reflex, while 1 mg/kg/day naloxone tended to slow development. Low dose females had significantly more errors than controls on the first day of maze learning. The high dose group had a significantly higher concentration of granule cells in the curvature of the dentate gyrus than controls; other neuroanatomical measures were unaffected by dosing. These findings confirm and extend previous work indicating that prenatal exposure to naloxone may alter neurobehavioral development in the rat.
Shepanek
N A
NA
Department of Psychology, George Mason University, Fairfax, VA 22030.
Smith
R F
RF
Tyer
Z E
ZE
Royall
G D
GD
Allen
K S
KS
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D001921:Brain / Q000033:anatomy & histology / Q000187:drug effects*; D002531:Cerebellum / Q000187:drug effects; D005260:Female; D006624:Hippocampus / Q000187:drug effects; D007858:Learning / Q000187:drug effects; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009044:Motor Cortex / Q000187:drug effects; D009270:Naloxone / Q000633:toxicity*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D051381:Rats; D012018:Reflex / Q000187:drug effects
D009270:Naloxone