The reports of analgesic effects of benzodiazepines are inconsistent. There is evidence of a hyperalgesic effect induced by activation of supraspinal GABAA receptors and an antinociceptive effect induced by activation of receptors located in the spinal cord (dorsal horns). The aim of the study was to discover whether the systemic administration of a benzodiazepine agent alprazolam increases the systemic analgesic efficacy of non-opioid analgesic ibuprofen. Experimental studies combining these agents have not yet been published. We used three experimental methods - writhing test (with acetic acid), tail-flick test and plantar test to assess analgesic action. The drugs were administered orally. Augmentation of the analgesic effect of ibuprofen by alprazolam was proved for the writhing test at a dose of 30 mg/kg of ibuprofen and alprazolam 1 mg/kg. The reaction time of the combination was significantly prolonged in comparison with ibuprofen alone. The results of the tail-flick test and plantar test were negative. The effect of ibuprofen was not enhanced by alprazolam in tests of acute thermal pain. Our results have demonstrated that the analgesic action of ibuprofen is only weakly enhanced by alprazolam., T. Doležal, M. Kršiak., and Obsahuje bibliografii
Knowledge on the involvement of spinal COX-1 and COX-2 in pain due to osteoarthritis could be useful for better understanding of its pa thogenesis and therapy. In this study we have investigated a long-term pattern of expression and production of spinal COX-1 and COX-2 in the model of osteoarthritis induced in rats by injection of monoiodoacetate (MIA) into the knee joint. MIA injection produced thermal hyperalgesia (assessed by the plantar test) and tactile allodynia (measured with von Frey hairs). The pain measures reached maximum on the 5th day, then re mained relatively stable. The expression of spinal COX-2 mR NA reached maximum on day 5 (5.2 times; P<0.001) and remain ed increased until day 31 (4.9 times; P<0.001). Expression of spinal COX-1 mRNA increased gradually reaching maximum on the day 31 (4.5 times; P<0.001) when the relative expression of both genes was almost equal. The production of both proteins was almost similar at the beginning of the experiment. The highest production of COX-2 protein was observed on day 5 after the induction of osteoarthritis (increased 3.9 times). The levels of COX-1 protein increased gradually with maximum on day 31 (3.4 times). The present findings indicate that not only expression of COX-2 mRNA but also that of COX-1 mRNA is significantly increased in the spine during osteoarthritis pain. Thus, in contrast to inflammatory pain, the upregulation of spinal COX-1 may be important in osteoarthritis pain., M. Procházková, P. Zanvit, T. Doležal, L. Prokešová, M. Kršiak., and Obsahuje bibliografii