Ahmad S, Allescher H D, Manaka H, Manaka Y, Daniel E E
McMaster University Health Science Center, Hamilton, Ontario, Canada.
Am J Physiol. 1989 Jun;256(6 Pt 1):G957-65. doi: 10.1152/ajpgi.1989.256.6.G957.
Biochemical information about receptors for adrenergic and opioid neurotransmission in submucosal plexus (SMP) is unavailable. We have purified a fraction P2 enriched in synaptosomes and neuronal membranes (high [3H]saxitoxin binding and high vasoactive intestinal polypeptide immunoreactivity, low activity of 5'-nucleotidase) from the canine small intestine SMP. The synaptosomal fraction (fraction P2) also contained a high density of opioid diprenorphine binding sites of high affinity. [3H]rauwolscine binding was enriched both in fraction P2 and in a microsomal fraction. Competition experiments using several adrenergic and opioid receptor ligands revealed that opioid receptors were approximately 64% mu-, 24% delta-, and 12% kappa-subtypes and that adrenoceptors on fraction P2 were alpha 2-subtype but that there was a heterogeneous population of alpha 2-adrenoceptors. These studies show that a fraction enriched in synaptosomes and neural membranes from the canine intestine SMP contains opioid as well as alpha 2-adrenoceptors, that all three subtypes of opioid receptors seem to be present with mu-receptors predominant, and that subtypes of alpha 2-adrenoceptors appear to be present.
关于黏膜下神经丛（SMP）中肾上腺素能和阿片样物质神经传递受体的生化信息尚不清楚。我们从犬小肠SMP中纯化了一种富含突触体和神经元膜的组分P2（高[³H]石房蛤毒素结合力和高血管活性肠多肽免疫反应性，5'-核苷酸酶活性低）。突触体组分（组分P2）还含有高密度的高亲和力阿片样物质二丙诺啡结合位点。[³H]育亨宾结合在组分P2和微粒体组分中均有富集。使用几种肾上腺素能和阿片样物质受体配体进行的竞争实验表明，阿片样物质受体约64%为μ-亚型、24%为δ-亚型、12%为κ-亚型，组分P2上的肾上腺素能受体为α₂-亚型，但存在异质性的α₂-肾上腺素能受体群体。这些研究表明，犬小肠SMP中富含突触体和神经膜的组分含有阿片样物质以及α₂-肾上腺素能受体，所有三种阿片样物质受体亚型似乎都存在，其中μ-受体占主导，并且α₂-肾上腺素能受体亚型似乎也存在。
