Effect of amitriptyline on EAAs-IAAs concentration in cerebrospinal fluid of SNI rat

Aim To investigate the effect amitriptyline on EAAs-IAAs in spinal cord CSF of rats with spared nerve injury (SNI).Methods A total of 30 male SD rats were randomly divided into 3 groups with 10 rats in each group:control (A),SNI (B) and SNI+ amitriptyline (C) groups,which respectively were treated with intraperitoneal injections of 0.2 ml normal saline (A and B),10mg·kg-1 amitriptyline (C),bid.Mechanical pain threshold change of each group was measured and in vivo CSF Glu,Asp,GABA and Gly concentration were measured at the 0 day,1st day,3rd day,and 5th day after model was made.Results Compared with control,group B had a markedly decreased rat mechanical pain threshold (P0.01) and an obviously high expression of Glu and Asp levels at the corresponding time points(P0.01).GABA and Gly expression were increased in 1st day after surgery(P0.01and P0.05) and decreased in 3th day after surgery(P0.01 and P0.05) and decreased in 5th day after surgery(P0.01).And group C,compared with group B,mechanical pain threshold was markedly increased(P0.01).Not only Glu and Asp expression were significantly decreased in 3rd and 5th day after surgery(P0.01),but also GABA and Gly expression had a marked increase in 5th day after surgery(P0.01).Conclusion This result provides a new line of evidence that amitriptyline can restore of EAAs-IAAs balance at the spinal level to prevent peripheral injury,which may be one of its mechanisms in the treatment of neuropathic pain.