Leila Amini Noghondar - Student Research Committee, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
Niloufar Jafari - Department of Neurology, Faculty of Medicine, Mashhad University of Medical sciences, Mashhad, Iran
Hassan Abbassian - Department of Neurology, Faculty of Medicine, Mashhad University of Medical sciences, Mashhad, Iran

Essential tremor (ET) is a progressive neurological impairment and mostly cause unnecessary rhythmic movements mainly in upper extremity. Based on disease severity, its treatment is different and present agents don’t show progressive and successful outcome in 25-55% of cases. Since present treatment protocols have serious side effects, we decided to test the effects of chamomile hydro alcoholic extract on passive avoidance memory in harmaline induced rat model of tremor. Materials and Methods: 40 male rats (weighing 40-60 g) were kept in individual cages with access to food and water ad-libitum in a 12/12 dark/light cycle. The animals divided into 5 groups of 8, including control saline,Harmaline 10 mg/kg, chamomile 50, 100, 200 mg/kg IP. Animals were placed in the light arena of the shuttlebox and the door opened and allowed to go to the dark sector without electric shock. When the animal entered the dark sector, an electric pulse was administered to thecage floor (0.5A, 5ms). In the retention trials, 24 h after training, the test was performed to evaluate memory; for this, the animal was placed in the light arena of the shuttle-box apparatus. After 30 s, the door opened and the time required to enter the dark sector was recordedas retention time (step-through latency (STL)). Time in the dark compartment (TDC) was recorded as an indicator of contextual memory. Results: Significant STL improvement was detected through chamomile groups. In addition, more drug dosage caused significantimprovement in STL (34.8±5.97, 59.1±11.63, 89.7±9.14vs.34.0±5.18). After Harmaline injection TDC showed significant increase in comparison with control.The more we injected chamomile, greater reduction was detected in TDC (101.4±44.38, 58.5±11.68, 49.4±9.58vs.112.9±38.65). Conclusion: Although more assessments needed, our results showed chamomile may make place in ET treatment