Biochemical studies on opioid and alpha 2-adrenergic receptors in canine submucosal neurons.
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.
Ahmad
S
S
McMaster University Health Science Center, Hamilton, Ontario, Canada.
Allescher
H D
HD
Manaka
H
H
Manaka
Y
Y
Daniel
E E
EE
D015720:5'-Nucleotidase; D000818:Animals; D001667:Binding, Competitive; D002462:Cell Membrane / Q000378:metabolism; D004174:Diprenorphine / Q000378:metabolism; D004285:Dogs; D007413:Intestinal Mucosa / Q000294:innervation*; D007421:Intestine, Small / Q000294:innervation*; D007700:Kinetics; D009474:Neurons / Q000378:metabolism*; D009708:Nucleotidases / Q000378:metabolism; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D011957:Receptors, Opioid / Q000378:metabolism*; D012530:Saxitoxin / Q000378:metabolism; D013574:Synaptosomes / Q000378:metabolism; D014660:Vasoactive Intestinal Peptide / Q000032:analysis; D015016:Yohimbine / Q000378:metabolism
D011942:Receptors, Adrenergic, alpha; D011957:Receptors, Opioid; D004174:Diprenorphine; D015016:Yohimbine; D012530:Saxitoxin; D014660:Vasoactive Intestinal Peptide; D009708:Nucleotidases; D015720:5'-Nucleotidase