INDUCTIONS OF CU ZN SUPEROXIDE DISMUTASE-LIKE AND NITRIC-OXIDE SYNTHASE-LIKE IMMUNOREACTIVITIES IN RABBIT SPINAL-CORD AFTER TRANSIENT ISCHEMIA/

The distributions and inductions of Cu/Zn superoxide dismutase (SOD), neuronal and endothelial nitric oxide (NO) synthase (nNOS and eNOS), a nd nitrotyrosine (NT) were immunohistochemically examined in rabbit sp inal cords after 5 and 15 min of transient ischemia. The neurons in th e anterior horns (AH) were selectively lost 7 days after 15-min ischem ia as compared with those of sham-operated controls. In the normal spi nal cords, a number of neurons in the AHs were positive for the nNOS, and only slightly positive for the Cu/Zn SOD and the eNOS. Immunoreact ivities for the proteins were induced at 8-24 h both after 5- and 15-m in ischemia. In contrast, NT-like immunoreactivity was negative both i n the normal and postischemic spinal cords. These results suggest that Cu/Zn SOD- and nNOS-, and eNOS-like immunoreactivities are induced, b ut that, even though an interaction of Cu/Zn SOD with NO could be pres ent, NT was not detected in the motor neurons in the rabbit spinal cor ds after transient ischemia. Other factors could be required for NT fo rmation found in degenerative motor neuron death in humans.