Abstract

Background: Burden of substance abuse is becoming a worldwide problem. One of the substances widely consumed in Ethiopia and other East African countries is Catha edulis Forsk (khat). Most of abusers complained that its stimulatory effect is the determinate factor makes them to chew. However, its rewarding and reinforcing potential and variation between sexes has not been investigated. This study was designed to measure the rewarding effects of khat extract in addiction mice model of both sexes.

Materials and Methods: 48 Swiss albino mice of both sexes of age 6-7 weeks having 21-27g body weight were used. The mice were conditioned to khat extract (ke) (100 mg/kg, 200 mg/kg and 300 mg/kg b.w) for 20 days. Control group was conditioned to tween 80 (2%, v /v) in distilled water. The reinforcing effect of khat was evaluated using conditioned place preference (CPP) paradigm. The classical pairing to the extract was made using the place conditioning box. Post-condition tests have been conducted four times and the average values were taken for analysis using SPSS version 21.0.

Results: Time spent in khat paired compartment was higher significantly for mice conditioned to ke 200 mg/kg (p<0.05) and ke 300 mg/kg (p<0.001). The rewarding effects of khat was strong in females at a higher dose when compared with the same sex of mice conditioned to vehicle (p<0.001) or male sex of mice conditioned to the same dose of khat extract (p<0.05). Repeated administration increased khat rewarding sensitization at all dose groups.

Conclusions: Mice showed place conditioning to khat extract and were strong in females. The genes expression alteration induced by khat extract between sexes should be investigated.

Keywords: Addiction, Addiction research, Addiction therapy, Substances use disorders, Conditioned place preference, khat, Place condition score, Time spent in the khat paired compartment