TY - JOUR
T1 - The role of 5-HT receptor subtypes in the ventrolateral orbital cortex of 5-HT-induced antinociception in the rat
AU - Qu, C. L.
AU - Huo, F. Q.
AU - Huang, F. S.
AU - Li, Y. Q.
AU - Tang, J. S.
AU - Jia, H.
PY - 2008/3/18
Y1 - 2008/3/18
N2 - The present study examined the involvement of 5-HT in the ventrolateral orbital cortex (VLO) on descending antinociception and determined which subtypes of 5-HT receptors mediated this effect. This study focused on the effects of 5-HT microinjection in the VLO of lightly anesthetized male rats on the radiant heat-evoked tail flick (TF) reflex, as well as the influence of 5-HT1A, 5-HT2, 5-HT3, and 5-HT4 receptor subtype antagonists on the effect of 5-HT. Results showed that 5-HT microinjection (2, 5, 10 μg, in 0.5 μl) into the VLO depressed the TF reflex in a dose-dependent manner. Pretreatment with 5-HT receptor antagonists (1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl] piperazine hydrobromide (NAN-190), cyproheptadine hydrochloride (CPT) and 1-methyl-N-(8-methyl-8-azabicyclo[3.2.3]-oct-3-yl)-1H-indazole-3-carboxamide maleate salt (LY-278,584)), specific for 5-HT1A, 5-HT2 and 5-HT3 receptors, respectively, partially reversed the 5-HT-evoked inhibition. In contrast, the 5-HT4 receptor antagonist, 1-[2-[(methylsulfonyl)-amino]ethyl]-4-piperidinyl]methyl1-methyl-1H-indole-3-carboxylate (GR 113808), had no effect on the inhibition of 5-HT. Microinjections of NAN-190, CPT and LY-278,584 alone into the VLO had no effect on the TF reflex. These results suggest that 5-HT1A, 5-HT2 and 5-HT3, but not 5-HT4 receptors, are involved in mediating 5-HT-induced antinociception in the VLO. According to different properties and distribution patterns of the 5-HT receptor subtypes on neurons, the possible mechanism of 5-HT activation of the VLO-periaqueductal gray (PAG) descending antinociceptive pathway is discussed.
AB - The present study examined the involvement of 5-HT in the ventrolateral orbital cortex (VLO) on descending antinociception and determined which subtypes of 5-HT receptors mediated this effect. This study focused on the effects of 5-HT microinjection in the VLO of lightly anesthetized male rats on the radiant heat-evoked tail flick (TF) reflex, as well as the influence of 5-HT1A, 5-HT2, 5-HT3, and 5-HT4 receptor subtype antagonists on the effect of 5-HT. Results showed that 5-HT microinjection (2, 5, 10 μg, in 0.5 μl) into the VLO depressed the TF reflex in a dose-dependent manner. Pretreatment with 5-HT receptor antagonists (1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl] piperazine hydrobromide (NAN-190), cyproheptadine hydrochloride (CPT) and 1-methyl-N-(8-methyl-8-azabicyclo[3.2.3]-oct-3-yl)-1H-indazole-3-carboxamide maleate salt (LY-278,584)), specific for 5-HT1A, 5-HT2 and 5-HT3 receptors, respectively, partially reversed the 5-HT-evoked inhibition. In contrast, the 5-HT4 receptor antagonist, 1-[2-[(methylsulfonyl)-amino]ethyl]-4-piperidinyl]methyl1-methyl-1H-indole-3-carboxylate (GR 113808), had no effect on the inhibition of 5-HT. Microinjections of NAN-190, CPT and LY-278,584 alone into the VLO had no effect on the TF reflex. These results suggest that 5-HT1A, 5-HT2 and 5-HT3, but not 5-HT4 receptors, are involved in mediating 5-HT-induced antinociception in the VLO. According to different properties and distribution patterns of the 5-HT receptor subtypes on neurons, the possible mechanism of 5-HT activation of the VLO-periaqueductal gray (PAG) descending antinociceptive pathway is discussed.
KW - 5-HT
KW - 5-HT receptor
KW - antinociception
KW - rat
KW - tail flick reflex
KW - ventrolateral orbital cortex
UR - https://www.scopus.com/pages/publications/40849139137
U2 - 10.1016/j.neuroscience.2007.09.036
DO - 10.1016/j.neuroscience.2007.09.036
M3 - 文章
C2 - 18295406
AN - SCOPUS:40849139137
SN - 0306-4522
VL - 152
SP - 487
EP - 494
JO - Neuroscience
JF - Neuroscience
IS - 2
ER -