1.Anti-allodynic Efficacy of NMDA Antagonist Peptide and Noradrenaline Alone and in Combination in Rodent Neuropathic Pain Model.
Farinaz NASIRINEZHAD ; Marjan HOSSEINI ; Sajad SALARI
The Korean Journal of Pain 2015;28(2):96-104
BACKGROUND: The present experiment was conducted to identify the cooperative effect of serine histogranin (SHG) and noradrenaline in alleviating peripheral neuropathic pain. METHODS: Chronic constriction injury of the right sciatic nerve was used to induce chronic neuropathic pain. For drug delivery, a PE10 tube was inserted into the subarachnoid space. Acetone drops and a 44degrees C water bath were used to evaluate the cold and heat allodynia, respectively. Placing and grasping reflexes were used to assess the locomotor system. RESULTS: SHG at 0.5 and 1 microg significantly (P < 0.05) decreased the thermal allodynia. The cold allodynia was also significantly reduced by intrathecal injections of 0.5 (P < 0.05) and 1 microg (P < 0.001) of SHG. 1 microg of noradrenaline, but not 0.5 microg, significantly alleviated the cold (P < 0.01) and thermal (P < 0.05) allodynia. The ameliorating effect of noradrenaline or SHG disappeared when the two compounds were administrated in equal concentrations. A significant difference (P < 0.01 in the acetone and P < 0.05 in the heat) was observed in the groups under equal doses of the two compounds, with a lower effectiveness of the combination therapy. CONCLUSIONS: Our findings suggest that the simultaneous administrations of noradrenaline and SHG do not result in synergistic analgesia, and combination therapy may not be a good approach to the treatment of chronic neuropathic pain syndrome.
Acetone
;
Analgesia
;
Baths
;
Constriction
;
Hand Strength
;
Hot Temperature
;
Hyperalgesia
;
Injections, Spinal
;
N-Methylaspartate*
;
Neuralgia*
;
Norepinephrine*
;
Reflex
;
Rodentia*
;
Sciatic Nerve
;
Serine
;
Subarachnoid Space
;
Water