ABSTRACT
In this brief review of the possible link between age-related behavioral disorders and brain folate levels, preliminary data on humans and animals are presented. These data indicate that folate administration may improve some age-related behavioral dysfunctions. In aged humans and rats, there is a defect in the absorption of dietary folate, leading perhaps to a decrease in brain folate levels. If so, folate therapy may replenish brain stores of folates and may reverse some age-related behavioral deficits. Some questions concerning the possible relationship among mood status, intellectual functions, and folate levels in aging are discussed.
Subject(s)
Aging/psychology , Behavior/drug effects , Folic Acid/therapeutic use , Animals , Brain/metabolism , Disease Models, Animal , Folic Acid/blood , Folic Acid Deficiency/epidemiology , Humans , PrevalenceABSTRACT
The activity of 5-HT was manipulated by means of the peripheral injection of 5-HT reuptake inhibitors, fenfluramine and fluoxetine. These drug treatments, at doses higher than 1 mg/kg, produced retrograde amnesia in a one-trial appetitive learning task in rats. A non-specific inhibitor of 5-HT reuptake, imipramine, did not produce this amnesic effect, nor did the combination of fenfluramine with the MAOI tranylcypromine, although it produced, as expected, the "serotonergic syndrome." Results for the metabolic precursor of 5-HT, 5-HTP, also administered peripherally, were inconsistent, with amnesic effects seen at 5 and 20 mg/kg but none at 10 mg/kg.
Subject(s)
Memory/drug effects , Serotonin Antagonists/pharmacology , Serotonin/physiology , 5-Hydroxytryptophan/pharmacology , Animals , Avoidance Learning/drug effects , Drug Interactions , Fenfluramine/pharmacology , Fluoxetine/pharmacology , Imipramine/pharmacology , Lithium/pharmacology , Male , Rats , Rats, Inbred Strains , Tranylcypromine/pharmacologyABSTRACT
Rats learned one of two appetitive discrimination tasks varying in terms of cognitive difficulty. Contrary to previous reports showing an impairment in the acquisition of avoidance tasks under the effects of either chlorpromazine (CPZ) or lithium, the results of this experiment indicate that neither drug retards the acquisition of appetitive tasks. Instead, at the highest doses used (2 and 3 mg/kg), CPZ decreased the number of trials required for the difficult task. Rats administered CPZ had longer reaction times than rats administered placebo, and therefore might have achieved criterion earlier because they spent more time in front of and on the discriminanda. The contrary results reported with avoidance tests concerning the effects of CPZ are explained in terms of the anxiety-reducing properties of CPZ, which might reduce drive without impairing cognitive ability.
Subject(s)
Appetitive Behavior/drug effects , Chlorpromazine/pharmacology , Discrimination Learning/drug effects , Lithium/pharmacology , Animals , Male , Rats , Rats, Inbred StrainsABSTRACT
The effects of chlorpromazine on the acquisition of a brightness discrimination with food reward were examined. Doses of 0.5, 1.0 or 2.0 mg/kg of CPZ as well as saline were administered intraperitoneally to 4 groups of 7 Sprague-Dawley rats, 1 h prior to testing. After a 3-week period of habituation and pre-training, rats were tested 20 trials a day, 7 days a week. No drug effect was found on the number of trials to reach a criterion of 18/20 successive correct responses, which required an average of 6.2 days of training. Precriterion latencies, however, showed an increase as a function of increasing dose level. Post-choice latencies were not affected, eliminating motor retardation as an explanation for the latency effect.
