Inhibitory effect of opioids on sympathetic neurotransmission in the bovine iris
Inhibitory effect of opioids on sympathetic neurotransmission in the bovine iris
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阿片类药物对牛虹膜交感神经传递的抑制作用
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
S. Ohia
中科院分区：
文献类型：
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作者：
F. Anderson;S. Rice;C. Opere;K. al;S. Ohia
我们研究了阿片样物质和相关肽对分离的牛虹膜交感神经传递的影响。此外，我们评估了牛虹膜作为交感神经释放去甲肾上腺素（NE）药理学研究的可能模型的使用。预负荷[3h]NE的虹膜电刺激导致氚外排超过基础水平。释放放射性物质的色谱分析显示，未代谢的NE占过量组织氚外排总量的46.1±9.3% （n=5）。因此，电场刺激引起的氚外排被称为[3 H]NE释放。当外部钙浓度低于1.3 mM或存在ω - concontoxin（但不包括nitrendipine）时，电诱发的[3 H]NE溢出减弱，这表明钙通过电压依赖性神经元通道流入是牛虹膜交感神经释放NE所必需的。所有阿片类激动剂均抑制场刺激诱发的[3h]NE释放，效价顺序如下：布雷马辛>[D-Ala 2， D-Leu 5]-脑啡肽>[D-Ala 2, MePhe 4， Gly-ol 5]-脑啡肽>吗啡。纳洛酮（1 μM）可消除布雷马嗪和吗啡对NE释放的抑制作用。我们得出结论，阿片受体激动剂通过与眶前阿片受体相互作用损害牛虹膜的交感神经传递。
We investigated the effect of opioids and related peptides on sympathetic neurotransmission in the isolated, superfused bovine iris. Furthermore, we evaluated the use of the bovine iris as a possible model for pharmacological studies of norepinephrine (NE) release from sympathetic nerves. Electrical stimulation of irides preloaded with [ 3 H]NE caused an increase in tritium efflux over basal levels. Chromatographic analysis of released radioactive material showed that unmetabolized NE accounted for 46.1 ± 9.3% (n=5) of total tritium efflux from superfused tissues. Thus, field stimulation-induced tritium efflux was designated as [ 3 H]NE release. Electrically-evoked [ 3 H]NE overflow was attenuated when the external calcium concentration was lowered below 1.3 mM or in the presence of omega conotoxin (but not nitrendipine) indicating that an influx of calcium via voltage-dependent neuronal channels is necessary for NE release from sympathetic nerves in the bovine iris. All opioid agonists tested suppressed field stimulation-evoked [ 3 H]NE release with the following rank order of potency : bremazocine >[D-Ala 2 , D-Leu 5 ]-enkephalin > [D-Ala 2 , MePhe 4 , Gly-ol 5 ]-enkephalin > morphine. Naloxone (1 μM) abolished the inhibition of NE release caused by submaximal concentrations of bremazocine or morphine. We conclude that opioid agonists impair sympathetic neurotransmission in the bovine iris by interacting with prejunctional opioid receptors.