The development of brain biogenic amines, cyclic nucleotides and hyperactivity in 6-OHDA-treated rat pups.
Developmental changes in the behavior and brain biochemistry of rat pups were investigated in rats administered intracisternal injections of 6-hydroxydopamine (6-OHDA) or its vehicle at 5 days of age. Although pups of both groups were equivalent in their activity at 15 days of age, 6-OHDA-induced hyperactivity emerged at 20 and 30 days of age in a between-group design in which rats were only tested at one age. Body weight measurements revealed that 6-OHDA-treated rats were underweight at 15, 25 and 30 days of age. Furthermore, at 20 days of age, total activity was inversely related to body weights in the 6-OHDA-treated pups. Whole-brain levels of dopamine (DA) were decreased at every age by the 6-OHDA treatment, whereas norepinephrine (NE) levels were virtually unaffected by 6-OHDA at these same ages. Total activity was inversely correlated with whole-brain DA levels at 20 and 30 days of age when 6-OHDA-treated pups were hyperactive. Measures of cerebellar and "rest-of-brain" adenosine 3',5'-monophosphate (cyclic AMP) and guanosine 3',5'-monophosphate (cyclic GMP) were not uniformly altered by either the 6-OHDA treatment or by maturation. Results are discussed both in terms of brain biochemistry modulation of hyperactivity and the contribution of decreased body weights induced by 6-OHDA to the production of hyperactivity.
D000375:Aging; D000818:Animals; D001679:Biogenic Amines / Q000378:metabolism*; D001835:Body Weight; D001923:Brain Chemistry / Q000187:drug effects*; D000242:Cyclic AMP / Q000378:metabolism*; D006152:Cyclic GMP / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism; D006892:Hydroxydopamines / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects*; D009638:Norepinephrine / Q000378:metabolism; D016627:Oxidopamine; D051381:Rats; D011919:Rats, Inbred Strains
D001679:Biogenic Amines; D006892:Hydroxydopamines; D016627:Oxidopamine; D000242:Cyclic AMP; D006152:Cyclic GMP; D004298:Dopamine; D009638:Norepinephrine