Subarachnoid morphine reduces stimulation-induced but not basal expression of preproenkephalin in rat spinal cord.
Subarachnoid morphine reduces stimulation-induced but not basal expression of preproenkephalin in rat spinal cord.
复制标题
蛛网膜下腔吗啡降低了大鼠脊髓中刺激诱导的前脑啡肽原的表达，但不降低其基础表达。
DOI：
10.1097/00000542-199411000-00022
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发表时间：
1994
期刊：
影响因子：
8.8
通讯作者：
Uhl,GR
中科院分区：
文献类型：
--
作者：
Crosby,G;Marota,JJ;Goto,T;Uhl,GR
BackgroundTo evaluate directly the possibility that the potent exogenous opioid analgesic morphine may alter neuronal expression of opioid peptide genes, we assessed the effect of subarachnoid morphine on basal and noxious stimulation-induced expression of preproenkephalin in spinal cord neurons.MethodsTwenty male Sprague-Dawley rats were prepared 48 h in advance with lumbar subarachnoid catheters. In the first phase, basal expression was evaluated in rats that received morphine 10 micrograms or saline intrathecally (n= 5 per group). Subsequently, the experiment was repeated (n= 5 per group), except that 10 min after morphine or saline administration rats received a hindpaw footpad injection of 50 microliters 5% formalin. Rats were killed during pentobarbital anesthesia 2 h later, and messenger RNA transcribed from preproenkephalin was measured in lumbar spinal cord with quantitative in situ hybridization with a complementary sulfur 35-labeled oligonucleotide probe and emulsion autoradiography.ResultsIn control (nonstimulated) rats, 20% of the neurons in laminae I-II and 10% of those in laminae III-IV expressed preproenkephalin. Injection of formalin increased the fraction of positive neurons by 34%(P< 0.05) and 20%(P< 0.05) in laminae I-II and V-VI, respectively, but had no effect on expression in laminae III-IV. Subarachnoid morphine did not alter basal expression of preproenkephalin but markedly attenuated the noxious stimulation-induced increase in laminae I-II (P< 0.01) and V-VI (P< 0.05) by preventing the stimulation-evoked recruitment of preproenkephalin-expressing neurons that otherwise would have occurred.ConclusionsSubarachnoid morphine does not acutely alter basal expression of preproenkephalin in spinal cord neurons but inhibits the increase in preproenkephalin expression that would otherwise occur after noxious stimulation.
