Effects of Fennel Hydroalcoholic Extract on Passive Avoidance Memory in Harmaline Induced Tremor Rats

Essential tremor (ET) is a neurodegenerative dementia with partial to total cognitive and physical impairments which includes over 5% ofpeople worldwide. We still don’t have definite treatment for ET. This study sets out to assess the effect of the Fennel alcoholic extract on passive avoidance memory of tremor induced rat models. Materials and Methods: 40 male rats (weighing 40-60 g) were kept in individualcages with access to food and water ad-libitum in a 12/12 dark/light cycle. The animals divided in 5 groups of 8, including control saline, Harmaline 10 mg/kg, Fennel 50, 100, and 200 mg/kg IP. Animals placed in the light chamber of the shuttle - box, the door opened andallowed to enter the dark sector without electric shocks. When the animal entered the dark sector, an electric pulse was administered to cage floor (0.5A, 5ms). In retention trials, 24 h after training, the test performed to evaluate memory; so the animal was placed in the lightarena of the shuttle-box apparatus. After 30 s, the door opened and the time required to enter the dark sector was recorded as retention time (step-through latency (STL)). Time in the dark compartment (TDC) was recorded as an indicator of contextual memory. Results: STL inHarmaline group was significantly decreased. Significant STL improvement in fennel groups was observed in comparison with Harmaline group, but different drug dosage didn’t show any correlation (51.7±6.07, 51±7.08, 52.7±6.49vs.34.4±4.62). Although no TDC significantdifference was detected between different fennel groups, there was a meaningful TDC decrease in all experimental group in comparison with Harmalin group (84.2±14.50, 93.4±12.39, 94.8±11.27vs.129.4±39.43). Conclusion: present study revealed that fennel hydroalcoholic extractcan be considered in tremor treatment protocols.