title: Altered development of responsiveness to clonidine in severely malnourished rats.
abstract: To examine the effects of malnutrition on the ontogeny of alpha 2 noradrenergic receptor function, we compared the effects of clonidine during early development in severely malnourished and well-nourished rat pups. Independent groups of pups from dams given either 6% or 25% casein diets received one of five doses of clonidine at 5, 10, 15, 20 or 25 days of age and dose-response relationships for motor activity were determined. In the 25% pups the clonidine-induced locomotor activity was greatest at 5 and 10 days, intermediate at 15 days and not elevated at 20 and 25 days. The malnourished pups exhibited a significant delay in the transition from hyperactivity to hypoactivity, being activated by clonidine until at least 25 days. Wall-climbing measures indicated similar developmental trends as overall activity. These results are discussed in terms of the proposed mechanisms mediating the developmental change in the effects of alpha 2 receptor stimulation.
mesh_terms: D000375:Aging; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D003000:Clonidine / Q000494:pharmacology*; D005260:Female; D009043:Motor Activity / Q000187:drug effects*; D009748:Nutrition Disorders / Q000503:physiopathology*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D003000:Clonidine