酪胺使猫颈上神经节及瞬膜释放[3H]去甲肾上腺素的体外实验

In vitro release of [3H]noradrenaline by tyramine from the superior cervical ganglion and in the nictitating membrane of the cat.

Filinger E J

Instituto de Investigaciones Farmacológicas (CONICET), Buenos Aires, Argentina.

Gen Pharmacol. 1994 Sep;25(5):1045-9. doi: 10.1016/0306-3623(94)90117-1.

Abstract

The release and the metabolism of [3H]noradrenaline ([3H]NA) induced by tyramine was studied in the superior cervical ganglion (cell bodies) and in the nictitating membrane (nerve endings) of the cat. 2. Exposure of the ganglia to 58.0 and 174.0 microM tyramine resulted in the release of 13.7 and 11.8% respectively of the total tissue radioactivity. In the nictitating membrane, the fractional release of radioactivity was directly proportional to the concentration of tyramine (5.8, 58.0 and 174.0 microM). 3. In ganglia [3H]DOPEG accounted for 55.8% of the radioactivity released by 58.0 microM tyramine and only 10.5% of the radioactivity was unmetabolized NA. In presence of 174.0 microM tyramine, [3H]NA increased to 28.0% of the total radioactivity and [3H]DOPEG and [3H]OMDA decreased to 45.3 and 18.9% respectively. 4. In the nerve endings, the contribution of [3H]NA, [3H]DOMA and [3H]NMN increased with the concentration of tyramine while [3H]DOPEG decreased. 5. The deamination is the first step of the metabolic inactivation of [3H]NA induced by tyramine in the cell body of the postganglionic adrenergic neuron while in the nerve endings [3H]NA is preferentially O-methylated.

摘要

研究了酪胺诱导的[3H]去甲肾上腺素（[3H]NA）在猫颈上神经节（细胞体）和瞬膜（神经末梢）中的释放及代谢。2. 将神经节暴露于58.0和174.0微摩尔/升的酪胺中，分别导致总组织放射性的13.7%和11.8%释放。在瞬膜中，放射性的释放分数与酪胺浓度（5.8、58.0和174.0微摩尔/升）成正比。3. 在神经节中，[3H]DOPEG占58.0微摩尔/升酪胺释放放射性的55.8%，仅10.5%的放射性是未代谢的NA。在174.0微摩尔/升酪胺存在下，[3H]NA增加到总放射性的28.0%，[3H]DOPEG和[3H]OMDA分别降至45.3%和18.9%。4. 在神经末梢中，[3H]NA、[3H]DOMA和[3H]NMN的贡献随酪胺浓度增加而增加，而[3H]DOPEG减少。5. 脱氨是节后肾上腺素能神经元细胞体中酪胺诱导的[3H]NA代谢失活的第一步，而在神经末梢中[3H]NA优先发生O-甲基化。