Effect of various 6-hydroxydopamine treatments during development on growth and ingestive behavior.
Destruction of catecholamine-containing fibers in brain at 5 days of age with intracisternal injection of 6-hydroxydopamine reduced body growth, intake of a sucrose solution, and acquisition of an active avoidance response. Further characterization of behavioral deficits indicated that treated animals also showed reduced ingestion of saline solution when injected with desoxycorticosterone and a decreased eating response to insulin. In addition, all of these deficits produced by catecholamine depletion with 6-hydroxydopamine were observed in rats in which brain dopamine was preferentially reduced but not in rats having preferential destruction of noradrenergic fibers, suggesting that dopamine depletion amounts for the observed alterations in developing animals. Although animals treated with 6-hydroxydopamine at 14 days showed reduced intake of a sucrose solution, they did not have reduced growth. Since early malnourishment reduced growth, it seems possible that the reduced growth observed after destruction of dopaminergeic fibers may be related to an acute reduction of food intake which is perpetuated by persistent deficits in ingestive behavior. Evidence implicating malnourishment in other deficits produced by 6-hydroxydopamine could not be obtained.
Effect of various 6-hydroxydopamine treatments during development on growth and ingestive behavior. Destruction of catecholamine-containing fibers in brain at 5 days of age with intracisternal injection of 6-hydroxydopamine reduced body growth, intake of a sucrose solution, and acquisition of an active avoidance response. Further characterization of behavioral deficits indicated that treated animals also showed reduced ingestion of saline solution when injected with desoxycorticosterone and a decreased eating response to insulin. In addition, all of these deficits produced by catecholamine depletion with 6-hydroxydopamine were observed in rats in which brain dopamine was preferentially reduced but not in rats having preferential destruction of noradrenergic fibers, suggesting that dopamine depletion amounts for the observed alterations in developing animals. Although animals treated with 6-hydroxydopamine at 14 days showed reduced intake of a sucrose solution, they did not have reduced growth. Since early malnourishment reduced growth, it seems possible that the reduced growth observed after destruction of dopaminergeic fibers may be related to an acute reduction of food intake which is perpetuated by persistent deficits in ingestive behavior. Evidence implicating malnourishment in other deficits produced by 6-hydroxydopamine could not be obtained.