post-operative pain and its management remains one of the most important issues in the field of surgery and health care system. on the other hand, opioid drug abuse has a large prevalence in iran. formalin test has been used as a method for assessing pain and analgesia in rats. in the present study, the post-operative pain in morphine addicted rats was compared with that of non-addicted ones us...

amitriptyline, a tricyclic antidepressant agent is used as one of the analgesic drugs in different kinds of pain. in the present study the effect of local (subcutaneous) injection of amitriptyline (50 and 100 µg) on the acute and chronic pain using formalin test, was investigated. our data show that local injection of amitriptyline to the paw receiving formalin, causes a decrease in pain in bot...

We tested the role of sex chromosome complement and gonadal hormones in sex differences in several different paradigms measuring nociception and opioid analgesia using "four core genotypes" C57BL/6J mice. The genotypes include XX and XY gonadal males, and XX and XY gonadal females. Adult mice were gonadectomized and tested 3-4 weeks later, so that differences between sexes (mice with testes vs....

Previous experiments have shown that noxious stimulation increases expression of the c-fos proto-oncogene in subpopulations of spinal cord neurons. c-fos expression was assessed by immunostaining for Fos, the nuclear phosphoprotein product of the c-fos gene. In this study, we examined the effect of systemic morphine on Fos-like immunoreactivity (FLI) evoked in the formalin test, a widely used m...

  There is evidence that sweeteners such as sucrose and saccharin interact with endogenous opioid systems. Further research has shown that feeding different concentrations of sucrose and saccharin alter latency in the tail-flick test. In this study, the influence of a 12-day regimen of different sweetening agents, sucrose (32%), saccharin (0.08%) and aspartame (0.16%) on morphine-induced analge...

Post-operative pain and its management remains one of the most important issues in the field of surgery and health care system. On the other hand, opioid drug abuse has a large prevalence in Iran. Formalin test has been used as a method for assessing pain and analgesia in rats. In the present study, the post-operative pain in morphine addicted rats was compared with that of non-addicted ones us...

Multimodal analgesia is designed to optimize pain relief by coadministering drugs with distinct mechanisms of action or by combining multiple pharmacologies within a single molecule. In clinical settings, combinations of monoamine reuptake inhibitors and opioid receptor agonists have been explored and one currently available analgesic, tapentadol, functions as both a µ-opioid receptor agonist a...

Considering the importance of a deeper understanding of the effect throughout life of opioid analgesia at birth, our objective was to determine whether morphine administration in early life, once a day for 7 days in 8-day-old rats, alters the nociceptive response over the short (P16), medium (P30), and long term (P60) and to evaluate which system is involved in the altered nociceptive response....

BACKGROUND An excess of excitatory pathway activation via N-methyl-D-aspartate (NMDA) receptors has been described in neuropathic pain that responds poorly to morphine. However, in this situation, several published data sets show that coadministration of NMDA receptor antagonists restores the efficacy of opioids. Considering that magnesium behaves like an NMDA receptor antagonist, we investigat...

effects of insulin (1, 2 and 3 iu/kg, i.p.), morphine (5mg/kg, i.p.), naloxone (5mg/kg, s.c.), insulin before morphine and after naloxone were studied in the formalin test of mice. formalin test was induced by intraplantar injection of formalin (20m, 5%). morphine alone and insulin with morphine decreased the first phase (0-5 min) of pain. naloxone increased the interphase (6-20 min) of nicicep...