Possible involvement of protein kinase C in the attenuation of the morphine-induced Straub tail reaction in diabetic mice.
To investigate the role of protein kinase C in the attenuation of the morphine-induced Straub tail reaction in diabetic mice, we examined the effects of protein kinase C activator or inhibitor on the i.c.v. morphine-induced Straub tail reaction in mice. This reaction was less in diabetic mice than in normal mice. Intracerebroventricular pretreatment with phorbol 12,13-dibutyrate (50 pmol), a potent protein kinase C activator, attenuated the morphine-induced Straub tail reaction in normal mice, but not in diabetic mice. I.c.v. pretreatment with calphostin C (10 pmol), a selective protein kinase C inhibitor, enhanced the reaction in diabetic mice, but not in normal mice. The dose-response curve for the morphine-induced Straub tail reaction in normal mice, but not in diabetic mice, was shifted to the right by i.c.v. pretreatment with phorbol 12,13-dibutyrate (50 pmol). Furthermore, i.c.v. pretreatment with calphostin C (3 pmol) shifted the dose-response curve to the left in diabetic mice, but not in normal mice. These results indicate that activation of protein kinase C reduces the morphine-induced Straub tail reaction in normal mice. Also, the attenuation of the morphine-induced Straub tail reaction in diabetic mice may be due in part to increased protein kinase C activity.
Ohsawa
M
M
Department of Pathophysiology and Therapeutics, Faculty of Pharmaceutical Sciences, Hoshi University, Tokyo, Japan.
Kamei
J
J
D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D007276:Injections, Intraventricular; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009020:Morphine / Q000494:pharmacology*; D009281:Naphthalenes / Q000494:pharmacology*; D010147:Pain Measurement / Q000187:drug effects*; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D011493:Protein Kinase C / Q000502:physiology*
D004791:Enzyme Inhibitors; D009281:Naphthalenes; C061465:calphostin complex; D015240:Phorbol 12,13-Dibutyrate; D009020:Morphine; D011493:Protein Kinase C