Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.5 (5'-nucleotidase)
 3,167 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Receptor binding of the opioid receptor antagonist, [3H]diprenorphine, which has a similar affinity to the various opioid receptor subtypes, was characterized in subcellular fractions derived from either longitudinal or circular smooth muscle of the canine small intestine with their plexuses (myenteric plexus and deep muscular plexus, respectively) attached. The distribution of opioid binding activity showed a good correlation in the different fractions with the binding of the neuronal marker [3H]saxitoxin but no correlation to the smooth muscle plasma membrane marker 5'-nucleotidase. The saturation data (Kd = 0.12 +/- 0.04 nM and maximum binding = 400 +/- 20 fmol/mg) and the data from kinetic experiments (Kd = 0.08 nmol) in the myenteric plexus were in good agreement with results obtained previously from the circular muscle/deep muscular plexus preparation. Competition experiments using selective drugs for mu [morphiceptin-analog (N-MePhe3-D-Pro4)-morphiceptin] ), delta (D-Pen2,5-enkephalin) and kappa (dynorphin 1-13, U50488-H) ligands showed the existence of all three receptor subtypes. The existence of kappa receptors was confirmed in saturation experiments using [3H] ethylketocycloazocine as labeled ligand. Two putative opioid agonists, with effects on gastrointestinal motility, trimebutine and JO-1196 (fedotozin), were also examined. Trimebutine (Ki = 0.18 microM), Des-Met-trimebutine (Ki = 0.72 microM) and Jo-1196 (Ki = 0.19 microM) displaced specific opiate binding. The relative affinity for the opioid receptor subtypes was mu = 0.44, delta = 0.30 and kappa = 0.26 for trimebutine and mu = 0.25, delta = 0.22 and kappa = 0.52 for Jo-1196. Thus, Jo-1196 had some selectivity for kappa receptors compared to trimebutine. We conclude that there are similar types of opioid receptors in the myenteric plexus and the deep muscular plexus and that specificity of function of opioid nerves must depend on differential location of receptor types on particular neurons. The action of trimebutine and related drugs could vary depending upon their interactions with various gut opioid receptors having different physiological roles.
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PMID:Interaction of trimebutine and Jo-1196 (fedotozine) with opioid receptors in the canine ileum. 185 39

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.
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PMID:Biochemical studies on opioid and alpha 2-adrenergic receptors in canine submucosal neurons. 254 1