Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 1997 Dec;283(3):1276-84.

Delta opioid modulation of the binding of guanosine-5'-O-(3-[35S]thio)triphosphate to NG108-15 cell membranes: characterization of agonist and inverse agonist effects

P G Szekeres  1 , J R Traynor
Affiliations
  • PMID: 9400003

Delta opioid modulation of the binding of guanosine-5'-O-(3-[35S]thio)triphosphate to NG108-15 cell membranes: characterization of agonist and inverse agonist effects

P G Szekeres et al. J Pharmacol Exp Ther. 1997 Dec.

Abstract

The ability of the delta opioid agonist DPDPE ([D-Pen2, D-Pen4]enkephalin) to stimulate binding of the GTP analog guanosine-5'-O-(3-[35S]thio)triphosphate ([35S]GTPgammaS) to pertussis toxin-sensitive G proteins has been characterized in membranes from NG108-15 mouse neuroblastoma X rat glioma cells. The presence of GDP, or its hydrolysis-resistant analog GDPbetaS, and Mg++ ions was essential to observe agonist-mediated stimulation of [35S]GTPgammaS binding, although the guanine dinucleotides alone had complex inhibitory and stimulatory effects on [35S]GTPgammaS binding. The relative ability of the delta antagonists benzylidenenaltrexone and naltriben to inhibit DPDPE-stimulated [35S]GTPgammaS binding suggested the opioid receptor involved was of the delta-2 subtype. Ligand binding assays demonstrated biphasic binding of these antagonists to this single receptor type. [35S]GTPgammaS binding was also stimulated by [D-Ser2,Leu5,Thr6]enkephalin > deltorphin II = DPDPE = etorphine > levallorphan = diprenorphine = nalorphine = naltrindole. The delta antagonists benzylidenenaltrexone, TIPP (Tyr-Tic-Phe-Phe) and naltriben had no effect, but ICI 174864 (N, N-diallyl-Tyr-Aib-Phe-Leu-OH) acted as an inverse agonist and inhibited [35S]GTPgammaS binding. Pertussis toxin pretreatment blocked agonist stimulation of [35S]GTPgammaS binding and also reduced basal binding, thus confirming the presence of constitutively active delta receptors. Replacement of Na+ in the assay buffer with K+ afforded an increased level of basal [35S]GTPgammaS binding and an apparent increase in both the inverse agonist activity of ICI 174864 and the agonist activity of the partial agonist diprenorphine relative to the full agonist [D-Ser2, Leu5,Thr6]enkephalin. The stimulation of [35S]GTPgammaS binding to NG108-15 cell membranes allows a functional measure of delta opioid activity that can provide systems of differing relative efficacy.

PubMed Disclaimer

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

Publication types

LinkOut - more resources