in this study, we investigated the interactive effects of intraperitoneal (i.p.) injections of three different phosphodiesterase inhibitors (pdeis) on morphine-induced analgesia in mice using tail-flick method. subcutaneous administration of morphine (1, 3 and 6 mg/kg) caused significant antinociceptive effects in a dose dependent manner. administration of pentoxifylline (12.5, 25, 50 and 100 m...

  Tolerance and dependence are two main problems that have limited morphine administration as an analgesic drug and they might be as a result of changes in the number and affinity of receptors, dysfunction of adenylate cyclase, impaired coupling between activated µ receptor and K+ channels, and changes in the K+ and Ca2+ channels. There are several reports concerning the role of some of these...

Increasing evidence suggests there is a sex difference in opioid analgesia of pain arising from somatic tissue. However, the existence of a sex difference in visceral pain and opioid analgesia is unclear. This was examined in the colorectal distention (CRD) model of visceral pain in the current study. The visceromotor response (vmr) to noxious CRD was recorded in gonadally intact male and femal...

background: usual dosage  of morphine  (10 mg/kg) induces  analgesia  and ultra-low dose (uld) of morphine (1 μg/kg); hyperalgesia, and  c-fibers are also bearing  μ- opioid receptors; here the importance  of c-fibers on pain and  morphine   induced  analgesia/hyperalgesia  is questioned   and  investigated    using   pain   evaluation methods and infant capsaicin treating  for c-fibers lesioni...

there is some evidence supporting the reduced activity of integrins following chronic administration of morphine. this reduction might play a role in morphine tolerance development. manganese binds to the extracellular domain of integrins and makes them to be activated. the effect of integrins activation using manganese on tolerance development to the analgesic effect of morphine was investigat...

Very small doses of intrathecal (IT) morphine (25– 200 mg) have been used in an effort to provide effective postoperative pain relief while minimizing side effects after cesarean delivery. We performed a doubleblinded study in 40 patients presenting for elective cesarean delivery in which IT morphine was administered along with oral hydrocodone/acetaminophen and other medications commonly admin...

UNLABELLED Very small doses of intrathecal (i.t.) morphine (25-200 microg) have been used in an effort to provide effective postoperative pain relief while minimizing side effects after cesarean delivery. We performed a double-blinded study in 40 patients presenting for elective cesarean delivery in which i.t. morphine was administered along with oral hydrocodone/acetaminophen and other medicat...

BACKGROUND After cardiac surgery adequate postoperative analgesia is necessary. We assessed analgesia using intrathecal morphine and clonidine. METHODS In a double-blind randomized study, 45 patients having coronary artery bypass graft surgery were allocated randomly to receive i.v. patient-controlled analgesia (PCA) morphine (bolus, 1 mg; lock-out interval, 7 min) (control group), either alo...

Mice were pretreated either acutely or chronically with morphine to test the effect of such pretreatments on the antagonism by naloxone of morphine-induced respiratory depression and analgesia and to compare the development of tolerance to the two effects. A s.c. injection of 20 mg/kg of morphine 6 hr before testing produced a shift of the apparent pA2 of morphine-naloxone for analgesia from 7....

Several variables have been reported to affect the expression of sex differences in the analgesic potency of morphine. Although the effect of genetic background on morphine analgesia has been well documented, the relevance of genotype to sex differences in morphine analgesia has rarely been considered. The present study investigated morphine dose-response relationships in male and female mice o...