The Effect of Central Administration of Methyl Jasmonate on Feeding Behaviors, and Hypothalamic Expression of Orexin 1 Receptor in Rats

INTRODUCTION: The active plant ingredients have been successfully used in modern medicine to control appetites and energy hemostasis. The present study was designed to evaluate the efficacy of phytohormone methyl jasmonate (MJ) on food-related behaviors in rats.
METHODS: The adult male Wistar rats were divided into different groups (7 rats per each), and infused intracerebroventriculary (i.c.v.) with MJ vehicle (DMSO) or MJ (2.5, 5 and 10 µg/rat). Then, the individual rats were placed in an automated open filed like apparatus to assess a 12-hour food- related activities in light and dark times. After behavioral tests, immunofluorescence staining of orexin 1 receptor (Orx1R) was studied in rats’ hypothalamus.
RESULTS: The data showed that central administration of MJ (2.5, 5 and 10 µg/rat) significantly decreased food intake in light and dark phases as compared to control group. Moreover, all the MJ -treated groups rats exhibited a decrease in visit to food container in light and dark times (p<0.001). In addition, rats infused with MJ at 5 µg, and 10 µg spent less time in the ports of food container in light and dark phases in comparison with control rats. Time in zone-related to food, and the locomotor activity were significantly decreased in MJ (5 µg) groups during light time, and in all MJ- injected groups in the dark time. Moreover, hypothalamic expression of Orx1R was significantly decreased in rats-treated with MJ (5 µg) as compared to control.
DISCUSSION AND CONCLUSION: Overall, the results indicated a potential of MJ to modulate feeding-related behavior, and Orx1R expression in hypothalamus in rats.