Basic and Clinical Neuroscience Journal

en Modulation of Different Phases of Formalin Test by Force Swim Stress Behavioral Neuroscience Behavioral Neuroscience Original Original Introduction: The formalin test is the most accepted chemical test for evaluation of nociception. It requires the injection of an adequate amount of formalin into the surface of the hindpaw. Formalin test consists of phase 1 (0-7 min) and phase 2 (15-60) in which the animal shows painful behaviors. These phases are separated with a quiet phase named interphase, in which the nociceptive responses are decreased or completely disappeared. Methods: The goal of the current study was to evaluate the effects of swim stress at different heights of water on different phases of the formalin test in male rats. Results: Swim stress decreased nociceptive behaviors in first phase and prolonged interphase or delayed the start of second phase in a water height dependent manner. Swim stress in 25 and 50cm completely abolished the nociceptive behaviours in phase 1. Discussion: The present results showed different pain modulation during different phases of the formalin test and elucidated the impact of swim stress on duration of interphase. Interphase considered as an inactive period, but a recent research has shown that active inhibitory mechanisms are involved in the modulation of pain during this period. Therefore, swim stress may consider as a useful tool for study of the basic inhibitory mechanisms underlying attenuation of nociceptive behaviors between phase 1 and 2 of the formalin test. Swim stress, Interphase, Formalin test, Pain. 303 307 http://bcn.iums.ac.ir/browse.php?a_code=A-10-257-6&slc_lang=en&sid=1 Mohammad Mohammad-Zadeh 1370031947532846005454 1370031947532846005454 No Cellular and Molecular Research Center, Department of Physiology & Pharmacology, School of Medicine, Sabzevar University of Medical Sciences, Sabzevar, Iran. Hassan Azhdari-Zarmehri hasan.azhdari@gmail.com 1370031947532846005455 1370031947532846005455 Yes Department of Basic Sciences, Torbat Heydariyeh University of Medical Sciences, Torbat Heydariyeh, Iran. Faeze Mosavi 1370031947532846005456 1370031947532846005456 No Cellular and Molecular Research Center, Qazvin University of Medical Sciences, Qazvin, Iran. Mohammad Shabani 1370031947532846005457 1370031947532846005457 No Neuroscience Research Center, Kerman University of Medical Sciences, Kerman, Iran.