en Physiology Physiology Original Research: Basic Science in Medicine Original Research: Basic Science in Medicine Transcutaneous electrical nerve stimulation (TENS) is an analgesia inducing method with increasing applications in clinical procedures. In this study we tried to evaluate the role of the adrenergic system and its different adrenoceptor subtypes in TENS-induced analgesia. Two types of low and high frequency electrical stimuli were used in rats through needle electrodes, inserted at the base of their tails, and different alpha and beta adrenergic agonist and antagonists were introduced to these animals. The tail immersion test was used as the analgesiometric test. Our results suggest that the noradrenergic system, through its u2 -receptor, has a significant role in electrical-induced analgesia. TENS, analgesia, adrenoceptors, rat tail immersion. 219 222 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-1-354&slc_lang=en&sid=1 S SEMNANIAN 20031947532846005095 20031947532846005095 Yes From the Department of Physiology, Tarbiat Modarres University, Tehran F MOTAMEDI 20031947532846005096 20031947532846005096 No the Department of Physiology, Shaheed Beheshti University of Medical Sciences, Tehran, Islamic Republic of Iran.