RABBANI M, JAFARIAN-DEHKORDI A, SOBHANIAN M. COMPARISON OF ACUTE AND CHRONIC EFFECTS OF NIFEDIPINE ON NALOXONE-PRECIPITATED MORPHINE WITHDRAWAL IN MICE. Med J Islam Repub Iran 2003; 17 (3) :251-257
URL:
http://mjiri.iums.ac.ir/article-1-690-en.html
From the Department of Pharmacology, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran. , rabanim@yahoo.com
Abstract: (4445 Views)
Mice were rendered tolerant and dependent to morphine by subcutaneous
injection of morphine over a period of 5 days. The effects of acute
and chronic administration of dihydropyridine calcium channel antagonist
nifedipine on the development of tolerance and naloxone-precipitated
morphine withdrawal signs were investigated. A single injection of
nifedipine proved to be effective in inhibiting some signs of morphine
withdrawal but ineffective in blocking the development of tolerance to the
ataxic action of morphine. The concurrent injections of nifedipine with
morphine prevented most signs of morphine withdrawal but failed to have
any effects on the development of tolerance to the ataxic action of morphine.
The results suggest that alterations in dihydropyridine-sensitive
calcium channels may be involved in the adaptations that occur on chronic
treatment with morphine. It is also possible to conclude that separate
mechanisms are involved in the development of tolerance and dependence.