The Effect of Four Weeks of Lemon Essential Oil Consumption and Swimming Training on Memory and Pain in Adult Male Mice

With age, some functions of the nervous system, including avoidance memory, are impaired. The beneficial effects of exercise on neurogenesis, increasing neuronal synapses, the treatment of mental disorders, helping improve brain injuries, and prevention of neurodegenerative diseases have been proven. Citrus limon is one of the plants mentioned in traditional medicine for its analgesic effects. Therefore, in the present study, the effect of four weeks of lemon essential oil consumption and swimming training on memory and pain in male mice was investigated. To this end, 40 male mice with a weight of 40±  5 g were studied. The mice were randomly divided into 4 groups including control, swimming group, group receiving lemon essential oil, and group of swimming training + consuming lemon essential oil. Swimming practice consisted of four weeks of swimming in water for 30 minutes per session and five sessions per week, and 50 mg/kg lemon essential oil was administered by gavage. The pain threshold was measured to evaluate the avoidance memory of the shuttle box using the tail flick test. The results showed that the essential oil of lemon and swimming training has significantly reduced pain (p < 0.001). Moreover, the combined consumption of lemon essential oil and swimming training increased memory in male mice (p < 0.001). Aerobic exercise, especially swimming, has had a positive effect on memory consolidation and reduction of pain threshold. Probably, consuming lemon essential oil due to the presence of strong antioxidants can reduce the feeling of pain and improve avoidance memory.