The effect of chronic administration of Apium graveolens aqueous extract on learning and memory in normal and diabetic rats

  Abstract   Introduction: Diabetes mellitus accompanies with disturbances in learning, memory, and cognitive skills in the human society and experimental animals. Considering the beneficial antidiabetic potential of Apium graveolens (AG ), this research study was conducted to evaluate the effect of chronic i.p. administration of AG on learning and memory in diabetic rats using passive avoidance and Y-maze tests.   Methods: Female Wistar rats were randomly divided into control, AG-treated control, diabetic, and AG-treated diabetic groups. AG treatment continued for 4 weeks. For induction of diabetes, streptozotocin was injected i.p. at a single dose of 60 mg/kg. For evaluation of learning and memory, initial latency (IL) and step-through latency (STL) were determined at the end of study using passive avoidance test. Meanwhile, alternation behavior percentage was determined using Y maze. Results: There was a significant increase (p<0.05) in IL in diabetic and AG-treated diabetic groups after 4 weeks as compared to control group. In this respect, there was no significant difference between diabetic and AG-treated diabetic groups. On the other hand, STL significantly decreased (p<0.05) in diabetic group and significantly increased (p<0.05) in AG-treated diabetic group as compared to control group at the end of study. In addition, STL did not significantly change in AG-treated control group in comparison with control group. In addition, results of Y-maze test showed that there is no significant difference between diabetic and Ag-treated diabetic groups and between control and Ag-treated control group regarding alternation behavior. Discussion: In summary, chronic oral administration of AG could enhance the consolidation and recall capability of stored information only in diabetic animals and did not affect spatial memory of diabetic animals.