caa a22 4500 606162917 CHVBK 20210128100641.0 cr unu---uuuuu 210128e20150601xx s 000 0 eng 10.1007/s11062-015-9522-1 doi (NATIONALLICENCE)springer-10.1007/s11062-015-9522-1 Reversible Inactivation of the Dorsal Raphe Nucleus Increases Morphine-Induced Antinociception in Tolerated but Not in Nontolerated Rats [Elektronische Daten] [A. Sarihi, B. Heshmatian, P. Pahlevani, A. Komaki, A. Haghparast] We examined possible effects of the state of the dorsal raphe nucleus (DRN) on morphine-induced antinociception in morphine-tolerated and nontolerated rats. Stereotaxically, lidocaine (2%) was applied to the DRN for its reversible inactivation. On the test day, all animals received 10 mg/kg morphine 10 min before the tail-flick test (induction of thermal acute pain), and the maximum antinociceptive effect (MPE) was measured. In the morphine-tolerated group, animals preliminarily received everyday introductions of 20 mg/kg morphine for four consecutive days. There was a significant increase in the MPE (%) in the lidocaine-treated group (with inactivation of the DRN) compared to the control group. However, there was no significant difference in morphine-induced antinociception between the saline- and lidocaine-treated groups. Nonetheless, the antinociceptive responses to morphine (MPE) in morphine-tolerated rats were more significant in animals treated with lidocaine compared to the control group. Our results suggest that lack of GABA in the locus coeruleus, which follows inhibition of serotonin release in the DRN during ablation, may cause adrenergic cell-induced analgesic effects. Springer Science+Business Media New York, 2015 pain nationallicence dorsal raphe nucleus nationallicence reversible inactivation nationallicence morphine tolerance nationallicence lidocaine nationallicence locus coeruleus nationallicence Sarihi A. Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran aut Heshmatian B. Neurophysiology Research Center, Urmia University of Medical Sciences, Urmia, Iran aut Pahlevani P. Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran aut Komaki A. Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran aut Haghparast A. Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran aut Neurophysiology Springer US; http://www.springer-ny.com 47/3(2015-06-01), 205-211 0090-2977 47:3<205 2015 47 11062 https://doi.org/10.1007/s11062-015-9522-1 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s11062-015-9522-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Sarihi A. Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran aut NATIONALLICENCE 700 1- Heshmatian B. Neurophysiology Research Center, Urmia University of Medical Sciences, Urmia, Iran aut NATIONALLICENCE 700 1- Pahlevani P. Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran aut NATIONALLICENCE 700 1- Komaki A. Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran aut NATIONALLICENCE 700 1- Haghparast A. Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran aut NATIONALLICENCE 773 0- Neurophysiology Springer US; http://www.springer-ny.com 47/3(2015-06-01), 205-211 0090-2977 47:3<205 2015 47 11062