Phorbol ester blocks the increase of a high affinity GTPase activity induced by delta 2-opioid receptor agonist in the mouse spinal cord.
The high affinity GTPase activity in the mouse spinal cord was increased in a concentration-dependent manner by a selective delta 2-opioid receptor agonist, [D-Ala2]deltorphin II (0.1-1 microM). This increase of GTPase activity induced by [D-Ala2]deltorphin II was completely blocked by co-incubation with a selective delta 2-opioid receptor antagonist, naltriben (0.1 microM). A protein kinase C activator, phorbol 12,13-dibutyrate (PDB; 0.1-10 microM), which given alone had no effect on basal GTPase activity, blocked dose-dependently the increase of GTPase activity induced by [D-Ala2]deltorphin II (1 microM). Our results indicate the possibility that activation of protein kinase C by phorbol ester uncouples the delta 2-opioid receptor from G-proteins in the spinal cord.
Narita
M
M
Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, USA.
Mizoguchi
H
H
Tseng
L F
LF
D000818:Animals; D004789:Enzyme Activation; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009842:Oligopeptides / Q000494:pharmacology*; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology*; D017465:Receptors, Opioid, delta / Q000819:agonists*; D013116:Spinal Cord / Q000187:drug effects* / Q000201:enzymology
D009842:Oligopeptides; D017465:Receptors, Opioid, delta; C060209:deltorphin II, Ala(2)-; D015240:Phorbol 12,13-Dibutyrate; D020558:GTP Phosphohydrolases