Morphine analgesia, tolerance and physical dependence in the adrenalectomized rat

Involvement of cyclic AMP and prostaglandins in morphine analgesia, tolerance and physical dependence.

Morphine tolerance and dependence in the rat intestine in vivo.

There has been no previous demonstration of opioid tolerance and dependence with respect to the propulsive and contractile activities of the gut in vivo. In the experiments described herein, morphine was administered continuously (1 mg/kg/hr s.c., 72 hr) and/or by bolus injection (2 mg/kg) and intestinal motility and transit were evaluated in unanesthetized rats. Tolerance in intestinal motilit...

α-Terpineol attenuates morphine-induced physical dependence and tolerance in mice: role of nitric oxide

Objective(s):Dependence and tolerance to opioid analgesics are major problems limiting their clinical application. a-Terpineol is a monoterpenoid alcohol with neuroprotective effects which is found in several medicinal plants such as Myrtus communis, Laurus nobilis, and Stachys byzantina. It has been shown that some of these medicinal plants such as S. byzantina attenuate dependence and toleran...

Effects of Caffeine on Morphine Tolerance and Analgesia in Mice

       Caffeine, an adenosine A1, A2A, and A2B receptor antagonist, is frequently used as an adjuvant analgesic in combination with non steroidal anti-inflammatory drugs or opioids. The aim of this study was to evaluate the effects of caffeine on preventing the development of morphine tolerance and analgesia in mice. In this study, different groups of mice recei...

Attenuation of morphine tolerance and dependence by thymoquinone in mice

Objectives: Dependence and tolerance are major restricting factors in the clinical use of opioid analgesics. In the present study, the effects of thymoquinone, the major constituent of Nigella sativa seeds, on morphine dependence and tolerance were investigated in mice. Materials and Methods: Male adult NMRI mice were made tolerant and dependent by repeated injections of morphine (50, 50, and 7...