Functional recovery of the spinal cord following ischemia and reperfusion injury.
OBJECTIVE
To study the changes of excitatory amino acids (EAAs) and intracellular calcium ([Ca2+]i), and the protective effect of EAAs receptor antagonists in the tissues of rabbit lumbar spinal cord after 40-minues ischemia and 4-hours reperfusion.


METHODS
Thirty healthy rabbits were divided into six groups: sham-operation, 40-minues ischemia, 4-hour reperfusion, ketamine and MgSO4 treatment, ketamine treatment, and saline treatment groups. The contents of EAAs (glutamate and aspartate) and [Ca2+]i were measured.


RESULTS
The contents of glutamate and aspartate were decreased to 15.18 micromol/g+/-2.33 micromol/g and 9.99 micromol/g+/-0.69 micromol/g, respectively; 13.75 micromol/g+/-2.58 micromol/g and 6.49 micromol/g+/-1.39 micromol/g after reperfusion. In the ischemia group, the [Ca2+]i was elevated to 221.2 microg/g+/-4.27 microg/g, and elevated further to 298.3 microg/g+/-9.26 microg/g after reperfusion, being significantly higher than that of ischemia and control groups. Ketamine could obviously increase the level of glutamate and aspartate and decrease the level of [Ca2+]i during the ischemia and reperfusion injury.


CONCLUSIONS
The excitotoxicity of EAAs and the overload of calcium induced by EAAs play a harmful role in ischemia and reperfusion injury. Ketamine has an effective inhibitory effect.
Liu
Bo
B
Institute of Orthopedics, Second Affiliated Hospital, Lanzhou Medical College, Lanzhou 730030, China. liuo1970@sina.com
Sun
Zhengyi
Z
Liao
Weihong
W
Jiang
Jianxin
J
D000818:Animals; D002118:Calcium / Q000032:analysis; D018846:Excitatory Amino Acids / Q000097:blood*; D005260:Female; D007511:Ischemia / Q000097:blood*; D008297:Male; D011817:Rabbits; D011897:Random Allocation; D017459:Receptors, Amino Acid / Q000037:antagonists & inhibitors; D015427:Reperfusion Injury / Q000097:blood*; D013116:Spinal Cord / Q000098:blood supply*
D018846:Excitatory Amino Acids; D017459:Receptors, Amino Acid; D002118:Calcium