RESUMO
Melittin, a major component of bee venom, produces a sustained decrease in mechanical threshold, and an increase in spontaneous flinchings and paw thickness, which are characteristics similar to those induced by whole bee venom. Melittin-induced nociception has been known to be modulated by the changes in the activity of excitatory amino acid receptors, voltage-dependent calcium channels, cyclooxygenase and serotonin receptors. The present study was undertaken to investigate the role of calcium chelators (TMB-8 & Quin 2) in melittin-induced nociceptive responses. Changes of mechanical threshold and spontaneous flinching behaviors were measured at a given time point following intraplantar injection of melittin (30microgram/paw). Intrathecal or intraplantar pre-administration and intrathecal post-treatment of TMB-8 and Quin 2 significantly prevented the melittin-induced reduction of mechanical threshold, and intraplantar or intrathecal pre-treatment of TMB-8 and Quin 2 suppressed melittin-induced flinching behaviors. These results indicate that calcium ion in the spinal dorsal horn neurons and peripheral nerves plays an important role in the production and maintenance of mechanical allodynia and spontaneous pain by melittin.
Assuntos
Animais , Ratos , Venenos de Abelha , Canais de Cálcio , Cálcio , Quelantes , Hiperalgesia , Íons , Meliteno , Nociceptividade , Nervos Periféricos , Células do Corno Posterior , Prostaglandina-Endoperóxido Sintases , Receptores de Glutamato , Receptores de SerotoninaRESUMO
Objective To study the effect of TMB 8 on cerebral blood flow(CBF) of focal cerebral ischemia in the rats.Methods CBF in the middle cerebral artery occlusion after the middle cerebral artery occlusion was measured by a Laser Doppler Flowmeter. TMB 8 was administered 30 min before occlusion and 20 min after occlusion respectively.Results CBF was reduced quickly. TMB 8 0.5,1,2 mg/kg was administered 30 min before occlusion of the middle cerebral artery.The dosage inhibited the reduction of CBF,20 min after occlusion, CBF was increased by TMB 8 1 mg/kg significantly.Conclusion TMB 8 could prevent and treat the reduction of CBF in focal cerebral ischemia of MCAO in the rats,and improved the supply of blood in ischemic area.