Evaluation of the effect of khat (Catha edulis) Forsk on spatial learning and memory in CBA mice using the Morris water maze task

Abstract

Khat (Catha edulis Forsk) is a psychoactive plant commonly used in East Africa, horn of Africa and the Arabian peninsula. Its effects are mainly modulated through the dopaminergic system similar to amphetamines. Psychoactive substances/ drugs of abuse affect their changes centrally by acting on the brain, altering the neurotransmitter system and structurally affecting the limbic Papez system. These substances can affect learning and memory by interfering with the medial temporal lobe structures and thus affecting spatial learning and memory. This study evaluated the effect of khat on CBA mice using a Morris water maze task which is a test of spatial learning and memory. Twenty CBA mice were divided into 5 groups and administered, intraperitoneally, 0.5 mls normal saline, 40, 120, and 360 mg/kg body .. weight of khat extract, respectively. The doses were given once daily for 17 days during which the animals were submitted to acquisition, reversal learning and reference tests in the Morris water maze. The study also investigated the effect on learning and memory of escalating, repeated high (run) doses of khat extract given to CBA mice. Twenty nine CBA mice were divided into groups of 5 - 7 animals. The animals were first subjected -to an escalating dose regime and then followed by repeated high (run) doses, or an escalating dose regime followed by single daily dose, or an -escalating dose regime followed by saline or saline followed by escalating dose regime of khat extract. The mice were tested in a Morris water maze for spatial learning and memory, The escape latency, swim path length, swim speed, quadrant time and quadrant swim distances were measured by the use of stop watch and video recording tracings.