吗啡耐受过程中大鼠脑内P物质的变化

Changes of P material in rat brain in morphine tolerance course

研究P物质在大鼠吗啡耐药之前后脑内的变化.在未用吗啡的大鼠侧脑室内注射5 nmol P物质和在吗啡耐受后的大鼠侧脑室内注射5nmol P物质都能产生止痛效应,但在同样的剂量下,止痛作用比对未用吗啡耐受性的大鼠要小得多.用免疫组织化学法测试,下丘脑和伏核中P物质免疫反应呈顺调节(下调节),而中脑导管(PAG)周围呈逆调节(上调节).研究表明,具吗啡耐受大鼠脑中P物质诱导的止痛作用相似的免疫反应说明P物质起着重要作用.

This text investigated changes of P material in hindbrain before morpine tolerance in rats. After injection of 5 nmol of P material in intracerebrovantricular, antinociceptive effect was engendered in both opioid - naive rats and rats with morphine tolerance. And the later was lower than the former at the same dosage. At the same time, there was downregulation of P material inmmunoreactivity in both hypothalamus and central nucleus of amygdala tested by immunohistochemical methods, whereas there was upregulation around periaqueductal gray （PAG）. This study demonstrated： the immunoreaction that was similar with the antinociceptive effect induced by P material in rat brain after morphine tolerance suggesting that P material may play an important part in morphine tolerance.