EFFECTS OF CALCITONIN ON CNS MONOAMINES FOLLOWING CARRAGEENAN-INDUCEDINFLAMMATION IN RATS

The present study examined the effects of systemically administered ca lcitonin (CT, 10 IU/0.25 ml, SC) on changes in CNS monoamines (MAs) fo llowing unilateral carrageenan (CARRA)-induced inflammation in the rat hindpaw. High-performance liquid chromatography with electrochemical detection (HPLC-EC) for MAs was performed on the whole brain and rostr al spinal cord. Carrageenan-evoked inflammation significantly increase d brain serotonin [5-hydroxytryptamine (5-HT)], norepinephrine (NE), a nd dopamine (DA) levels. CT significantly reduced these CARRA-induced elevations in brain MAs. Elevated spinal cord 5-HT and NE levels were observed in CARRA-treated animals. CT administration increased 5-HT an d NE in both the CARRA-treated animals and their saline controls. Spin al cord DA levels were not affected by either CARRA or CT administrati on. These findings suggest the involvement of CNS monoaminergic substr ates in CT-induced hypoalgesia in inflammatory nociception.