Regulation of cyclic AMP by the mu-opioid receptor in human neuroblastoma SH-SY5Y cells

J Neurochem. 1990 Oct;55(4):1390-6. doi: 10.1111/j.1471-4159.1990.tb03151.x.


The human neuroblastoma clonal cell line SH-SY5Y expresses both mu- and delta-opioid receptors (ratio approximately 4.5:1). Differentiation with retinoic acid (RA) was previously shown to enhance the inhibition of adenylyl cyclase (AC) by mu-opioid agonists. We tested here the inhibition of cyclic AMP (cAMP) accumulation by morphine under a variety of conditions: after stimulation with prostaglandin E1 (PGE1), forskolin, and vasoactive intestinal peptide (VIP), both in the presence and in the absence of the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX). Morphine inhibition of the forskolin cAMP response (approximately 65%) was largely unaffected by the presence of IBMX. In contrast, deletion of IBMX enhanced morphine's inhibition of the PGE1 and VIP cAMP response from approximately 50 to approximately 80%. The use of highly mu- and delta-selective agents confirmed previous results that inhibition of cAMP accumulation by opioids is mostly mu, and not delta, receptor mediated in SH-SY5Y cells, regardless of the presence or absence of IBMX. Because of the large morphine inhibition and the high cAMP levels even in the absence of IBMX, PGE1-stimulated, RA-differentiated SH-SY5Y cells were subsequently used to study narcotic analgesic tolerance and dependence in vitro. Upon pretreatment with morphine over greater than or equal to 12 h, a fourfold shift of the PGE1-morphine dose-response curve was observed, whether or not IBMX was added. However, mu-opioid receptor number and affinity to the mu-selective [D-Ala2, N-Me-Phe4, Gly5-ol]enkephalin were largely unaffected, and Na(+)- and guanyl nucleotide-induced shifts of morphine-[3H]naloxone competition curves were unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

MeSH terms

  • 1-Methyl-3-isobutylxanthine / pharmacology*
  • Alprostadil / pharmacology
  • Cell Line
  • Colforsin / pharmacology
  • Cyclic AMP / metabolism*
  • Enkephalin, Ala(2)-MePhe(4)-Gly(5)-
  • Enkephalin, D-Penicillamine (2,5)-
  • Enkephalins / metabolism
  • Humans
  • Kinetics
  • Morphine / pharmacology
  • Neuroblastoma
  • Receptors, Opioid / drug effects
  • Receptors, Opioid / metabolism*
  • Receptors, Opioid, delta
  • Receptors, Opioid, mu
  • Theophylline / analogs & derivatives*
  • Vasoactive Intestinal Peptide / pharmacology


  • Enkephalins
  • Receptors, Opioid
  • Receptors, Opioid, delta
  • Receptors, Opioid, mu
  • Enkephalin, Ala(2)-MePhe(4)-Gly(5)-
  • Colforsin
  • Vasoactive Intestinal Peptide
  • Morphine
  • Enkephalin, D-Penicillamine (2,5)-
  • Theophylline
  • Cyclic AMP
  • Alprostadil
  • 1-Methyl-3-isobutylxanthine