Abstract
Endogenous opioids and opioid receptors (i.e. endogenous opioid systems) are involved in carcinogenesis. Using homogenates of S20Y neuroblastoma (NB) cells grown in culture, the binding of a growth-selective ligand, [Me5]enkephalin, was examined to ascertain the zeta (ζ) opioid receptor. Specific and saturable binding of [3H]-[Met5]enkephalin was detected in NB cells; the data were consistent with a single binding site. Scatchard analysis yielded a Kd of 1.6 nM and a binding capacity Bmax off 48.1 fmol/mg protein; 14,000 receptors per cell were estimated. Binding was dependent on protein concentration, time, temperature, and pH, and was sensitive to 100 nM, but not 5 nM, Na+, Ca2+, and Mg2+; GppNHp at concentrations of 100-500 mM had little effect on binding. Optimal binding required protease inhibitors, and pretreatment of the tumor cell homogenates with trypsin markedly reduced [3H]-[Met5]enkphalin winding, suggesting that the binding site was proteinaceous in character. Displacement experiments indicated that [Met5]enkephalin was the most potent displacer of [3H]-[Met5]enkephalin. Cell density (log, confluence, postconfluence) did not alter the Kd or Bmax. This study serves as the first demonstration and characterization of the zeta (ζ) opioid receptor in tissue culture cells. The homogenous nature of NB cell cultures, along with the enrichment in receptor number, provides an excellent model system to isolate and purify the ζ receptor.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 181-186 |
| Number of pages | 6 |
| Journal | Brain research |
| Volume | 511 |
| Issue number | 2 |
| DOIs | |
| State | Published - Mar 19 1990 |
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All Science Journal Classification (ASJC) codes
- Neuroscience(all)
- Molecular Biology
- Clinical Neurology
- Developmental Biology
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Demonstration and characterization of zeta (ζ), a growth-related opioid receptor, in a neuroblastoma cell line. / Zagon, Ian; Goodman, Steven R.; McLaughlin, Patricia.
In: Brain research, Vol. 511, No. 2, 19.03.1990, p. 181-186.Research output: Contribution to journal › Article
TY - JOUR
T1 - Demonstration and characterization of zeta (ζ), a growth-related opioid receptor, in a neuroblastoma cell line
AU - Zagon, Ian
AU - Goodman, Steven R.
AU - McLaughlin, Patricia
PY - 1990/3/19
Y1 - 1990/3/19
N2 - Endogenous opioids and opioid receptors (i.e. endogenous opioid systems) are involved in carcinogenesis. Using homogenates of S20Y neuroblastoma (NB) cells grown in culture, the binding of a growth-selective ligand, [Me5]enkephalin, was examined to ascertain the zeta (ζ) opioid receptor. Specific and saturable binding of [3H]-[Met5]enkephalin was detected in NB cells; the data were consistent with a single binding site. Scatchard analysis yielded a Kd of 1.6 nM and a binding capacity Bmax off 48.1 fmol/mg protein; 14,000 receptors per cell were estimated. Binding was dependent on protein concentration, time, temperature, and pH, and was sensitive to 100 nM, but not 5 nM, Na+, Ca2+, and Mg2+; GppNHp at concentrations of 100-500 mM had little effect on binding. Optimal binding required protease inhibitors, and pretreatment of the tumor cell homogenates with trypsin markedly reduced [3H]-[Met5]enkphalin winding, suggesting that the binding site was proteinaceous in character. Displacement experiments indicated that [Met5]enkephalin was the most potent displacer of [3H]-[Met5]enkephalin. Cell density (log, confluence, postconfluence) did not alter the Kd or Bmax. This study serves as the first demonstration and characterization of the zeta (ζ) opioid receptor in tissue culture cells. The homogenous nature of NB cell cultures, along with the enrichment in receptor number, provides an excellent model system to isolate and purify the ζ receptor.
AB - Endogenous opioids and opioid receptors (i.e. endogenous opioid systems) are involved in carcinogenesis. Using homogenates of S20Y neuroblastoma (NB) cells grown in culture, the binding of a growth-selective ligand, [Me5]enkephalin, was examined to ascertain the zeta (ζ) opioid receptor. Specific and saturable binding of [3H]-[Met5]enkephalin was detected in NB cells; the data were consistent with a single binding site. Scatchard analysis yielded a Kd of 1.6 nM and a binding capacity Bmax off 48.1 fmol/mg protein; 14,000 receptors per cell were estimated. Binding was dependent on protein concentration, time, temperature, and pH, and was sensitive to 100 nM, but not 5 nM, Na+, Ca2+, and Mg2+; GppNHp at concentrations of 100-500 mM had little effect on binding. Optimal binding required protease inhibitors, and pretreatment of the tumor cell homogenates with trypsin markedly reduced [3H]-[Met5]enkphalin winding, suggesting that the binding site was proteinaceous in character. Displacement experiments indicated that [Met5]enkephalin was the most potent displacer of [3H]-[Met5]enkephalin. Cell density (log, confluence, postconfluence) did not alter the Kd or Bmax. This study serves as the first demonstration and characterization of the zeta (ζ) opioid receptor in tissue culture cells. The homogenous nature of NB cell cultures, along with the enrichment in receptor number, provides an excellent model system to isolate and purify the ζ receptor.
UR - http://www.scopus.com/inward/record.url?scp=0025357232&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0025357232&partnerID=8YFLogxK
U2 - 10.1016/0006-8993(90)90159-9
DO - 10.1016/0006-8993(90)90159-9
M3 - Article
C2 - 2159355
AN - SCOPUS:0025357232
VL - 511
SP - 181
EP - 186
JO - Brain Research
JF - Brain Research
SN - 0006-8993
IS - 2
ER -