Neonatal 6-hydroxydopamine alters the behavior of enriched-impoverished rats in a novel test environment.
The hypothesis that neonatal norepinephrine (NE) depletion lessens the behavioral consequences of differential housing was tested. Male Wistar rats were injected with 6-hydroxydopamine (6-OHDA) or vehicle twice within 24 hr of birth, weaned at 25 days, and reared under either impoverished (IC) or enriched conditions (EC) for 30 days. In 3 experiments, rats were tested in the Morris water maze, the colony-intruder test, and 2 tests of dominance. 6-OHDA treatment reduced cortical and hypothalamic NE concentrations and increased brainstem NE concentrations. EC housing increased cortical dopamine (DA). Behavioral differences caused by postweaning enrichment-isolation were reduced by neonatal NE depletion, primarily in early test trials. The authors conclude that forebrain NE afferents from the locus coeruleus are important for housing-related behavioral changes and responsivity to novel testing environments.
Saari
M J
MJ
Neuroscience Research Unit, Nipissing University College, North Bay, Ontario, Canada.
Armstrong
J N
JN
Nobrega
J N
JN
Pappas
B A
BA
Coscina
D V
DV
D000378:Agonistic Behavior / Q000187:drug effects; D000818:Animals; D000831:Animals, Newborn; D001522:Behavior, Animal / Q000187:drug effects*; D001921:Brain / Q000187:drug effects*; D003163:Competitive Behavior / Q000187:drug effects; D004193:Discrimination Learning / Q000187:drug effects; D004291:Dominance-Subordination; D004298:Dopamine / Q000378:metabolism; D004924:Escape Reaction / Q000187:drug effects; D006892:Hydroxydopamines / Q000494:pharmacology*; D008297:Male; D011939:Mental Recall / Q000187:drug effects; D009638:Norepinephrine / Q000378:metabolism; D009949:Orientation / Q000187:drug effects; D016627:Oxidopamine; D051381:Rats; D011919:Rats, Inbred Strains; D012931:Social Environment; D012934:Social Isolation; D013550:Swimming
D006892:Hydroxydopamines; D016627:Oxidopamine; D004298:Dopamine; D009638:Norepinephrine