Nogueira R L, Graeff F G
Laboratório de Neuropsicofarmacologia, Universidade de São Paulo, Ribeirão Preto, Brazil.
Pharmacol Biochem Behav. 1995 Sep;52(1):1-6. doi: 10.1016/0091-3057(94)00402-5.
To explore the role of 5-HT receptor subtypes in controlling aversion, we measured the effect of 5-HT1A and 5-HT2A/2C receptor agonists microinjected into the dorsal periaqueductal gray (DPAG) of rats on aversive behavior induced by electrical stimulation of the same brain area. The 5-HT1A agonists 8-OH-DPAT (4-16 nmol) and BAY-R-1531 (4-16 nmol) raised the threshold of aversive electrical stimulation in a dose-dependent way. Similarly, microinjection of the 5-HT2A/2C agonist DOI (4-16 nmol) increased the aversive mCPP (16 and 32 nmol) was ineffective. Previous intra-DPAG administration of the 5-HT1A receptor blocker NAN-190 (40 nmol) antagonized the antiaversive effect of 8-OH-DPAT (8 nmol), whereas pretreatment with the 5-HT2A receptor blocker spiperone (10 nmol) antagonized the effect of DOI (16 nmol). Spiperone also counteracted the effect of 8-OH-DPAT and NAN-190 counteracted the effect of DOI. These results indicate that activation of 5-HT1A and 5-HT2A receptors inhibits aversion in the DPAG and that both receptors have to be functional for the expression of each one's activation to occur.
为了探究5-羟色胺（5-HT）受体亚型在控制厌恶反应中的作用，我们测量了向大鼠中脑导水管周围灰质背侧（DPAG）微量注射5-HT1A和5-HT2A/2C受体激动剂对由相同脑区电刺激诱导的厌恶行为的影响。5-HT1A激动剂8-羟基二丙胺基四氢萘（8-OH-DPAT，4 - 16纳摩尔）和BAY-R-1531（4 - 16纳摩尔）以剂量依赖的方式提高了厌恶电刺激的阈值。同样，微量注射5-HT2A/2C激动剂DOI（4 - 16纳摩尔）增加了厌恶反应，而5-HT2C激动剂mCPP（16和32纳摩尔）则无效。先前向DPAG内注射5-HT1A受体阻断剂NAN-190（40纳摩尔）可拮抗8-OH-DPAT（8纳摩尔）的抗厌恶作用，而用5-HT2A受体阻断剂螺哌隆（10纳摩尔）预处理可拮抗DOI（16纳摩尔）的作用。螺哌隆也抵消了8-OH-DPAT的作用，NAN-190抵消了DOI的作用。这些结果表明，5-HT1A和5-HT2A受体的激活抑制了DPAG中的厌恶反应，并且两种受体都必须发挥功能才能使各自激活的表达发生。
