Pharmacology
-
Streptozotocin-induced hyperglycemia accompanied by a chronic decrease in the nociceptive threshold is considered a useful model of experimental hyperalgesia. We examined (1) the effect of the opioid receptor agonists and (2) the effect of the magnesium ions (Mg(2+)) on the antinociceptive action of opioid agonists in a diabetic neuropathic pain model. ⋯ However, pretreatment with Mg(2+) at a dose of 40 mg magnesium sulfate/kg i.p. markedly enhanced the analgesic activity of all three investigated opioids. Practical aspects of co-administration of magnesium and opioids in diabetic neuropathy are discussed.
-
There is considerable research evidence supporting a palliative role for gamma-aminobutyric acid (GABA)-ergic neurotransmission and voltage-gated sodium channel blockade in neuropathic pain conditions. Hence, the present study was undertaken to assess the peripheral analgesic, antiallodynic and antihyperalgesic activities of the synthesized structural analogues of GABA. ⋯ In this study, we have demonstrated that combining phthalimide pharmacophore with GABA has evolved compounds effective for the treatment of neuropathic pain.
-
Using a new animal model of postoperative pain we recently developed, we investigated whether the selective cyclooxygenase-2 (COX-2) inhibitor parecoxib sodium, and the analgesic tramadol hydrochloride, attenuated mechanical primary hyperalgesia induced by minor surgery on the rat tail. ⋯ We have shown that the hyperalgesia in our model of postoperative pain is responsive to treatment with the analgesic tramadol, but it is not responsive to the selective COX-2 inhibitor parecoxib at the doses we used.
-
The ovariectomized (OVX) rat, as an established animal model of human osteoporosis, was adopted in the present experiment to study the protective effects of sodium daidzein sulfonate (SDS) on trabecular bone. Six-month-old Sprague-Dawley rats were sham-operated or ovariectomized. Five days later, the OVX rats were randomly assigned to one of three experimental groups and treated for 90 days with vehicle, 17beta-estradiol (E(2)) or SDS. ⋯ In the OVX group, the structure of trabecular plate in the femoral head was absorbed and became progressively thinner or was removed completely, accompanied by enlargement of marrow cavities and amalgamation of two or more marrow cavities. Administration of SDS and E(2 )prevented the change of trabecular bone microarchitecture induced by OVX, increasing the trabecular bone area and trabecular thickness, while decreasing the trabecular separation. These results indicate that SDS administration prevents OVX-induced decrease in BMD and bone mechanical strength, and has a moderate protective effect on the microarchitecture of trabecular bone in aged Sprague-Dawley rats.