caa a22 4500 469078146 CHVBK 20180323132941.0 cr unu---uuuuu 170328e19920901xx s 000 0 eng 10.1007/BF00173548 doi (NATIONALLICENCE)springer-10.1007/BF00173548 Spinal 5-HT pathways and the antinociception induced by intramedullary clonidine in rats [Elektronische Daten] [M. Lin, C. Su] Summary: The possible involvement of spinal 5-hydroxytryptamine (5-HT) pathways in antinociception induced by microinjection of clonidine into the ventrolateral surface of the medulla oblongata was investigated in rats. Microinjection of clonidine (10-20 µg), but not yohimbine (1 µg) or 0.9% saline, into the lateral medulla prolonged the hot plate latency in rats. This clonidine-induced antinociception was abolished by intramedullary injection of the alpha2-adrenoceptor antagonist, yohimbine. Selective destruction of spinal 5-HT neurons produced by intraspinal injection of 5,7-dihydroxytryptamine (5,7-DHT; 10 µg) or postsynaptic blockade of spinal 5-HT receptors produced by intrathecal injection of cyproheptadine (1 µg; a mixed 5-HT1/5-HT2 antagonist) also abolished clonidine-induced antinociception. Rats given 5,7-DHT intraspinally or cyproheptadine intrathecally showed a decrease in hot plate latency as compared with the controls. In anesthetized rats, the 5-HT release from the thoracic spinal cord was enhanced by microinjection of clonidine into the lateral medulla. This enhanced spinal 5-HT release evoked by intramedullary injection of clonidine was abolished by pretreatment of rats with intraspinal injection of 5,7-DHT. These results indicate that 5-HT pathways to the spinal cord mediate the antinociceptive effect induced by microinjection of clonidine into the ventrolateral surface of the medulla oblongata in rats. Springer-Verlag, 1992 Antinociception nationallicence Clonidine nationallicence Serotonin nationallicence Spinal cord nationallicence Medulla oblongata nationallicence 5,7-Dihydroxytryptamine nationallicence Cyproheptadine nationallicence Yohimbine nationallicence Lin M. Department of Physiology, National Cheng Kung University Medical College, Tainan City, Taiwan, Republic of China aut Su C. Department of Surgery, National Defense Medical Center, Taipei, Taiwan, Republic of China aut Naunyn-Schmiedeberg's Archives of Pharmacology Springer-Verlag 346/3(1992-09-01), 333-338 0028-1298 346:3<333 1992 346 210 https://doi.org/10.1007/BF00173548 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00173548 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Lin M. Department of Physiology, National Cheng Kung University Medical College, Tainan City, Taiwan, Republic of China aut NATIONALLICENCE 700 1- Su C. Department of Surgery, National Defense Medical Center, Taipei, Taiwan, Republic of China aut NATIONALLICENCE 773 0- Naunyn-Schmiedeberg's Archives of Pharmacology Springer-Verlag 346/3(1992-09-01), 333-338 0028-1298 346:3<333 1992 346 210 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer