Catha edulis deteriorates spatial working memory in rats, but spares reference memory

The effects of Catha edulis, a CNS stimulant, on humans and animals have been studied on various aspects like anorectic effect, self-administration, stereotyped behavior, aggressive behavior, operant task, locomotor sensitization, psychosis etc., but how C. edulis influence spatial learning and memory in rats is not clear. C. edulis contains amphetamine like substances, which enhances spatial learning and memory. So, we hypothesize C. edulis will also influence spatial learning and memory. In the aim to assess this effect of C.edulis, a comparative study is conceded using another CNS stimulant, methylphenidate (MPD), which is currently used, for treatment of attention deficit hyperactive disorder (ADHD), instead of amphetamine. Spatial learning and memory was assessed using radial arm maze, by analyzing five dependent measures obtained on every trial: time to complete a trial, latency to first arm entry, number of reference memory errors, number of working memory correct and incorrect errors. Our results show that C. edulis and not MPD fed rats had impaired learning and memory, implicated by increased time to complete a trial. But both C. edulis and MPD increased attention in rats, as in both groups latency to first arm entry was less. Further analysis showed that C. edulis fed rats were more effected in the working memory component and reference memory was intact. These results highlight the importance of restricting the widespread use of C. edulis in humans. The use of MPD as a choice of drug in treatment of ADHD is also supported by this study as it did not deteriorate the learning and memory, in spite of increased attention and alertness. These results are further discussed on the basis of differential action of C. edulis and MPD on neurotransmitter systems of brain, and this reveals the need for detailed analysis in future studies for the effect of C. edulis on hippocampal network.