Intrathecally injected antibody can diffuse into spinal cord

Abstract

Antibody microinjection has been widely used to investigate the function of neuropeptides, but the capability of antibody to diffuse in the brain tissue has not been well characterized. The present study was conducted with an immunohistochemical method to determine if the anti-enkephalin serum injected intrathecally could diffuse into the spinal cord. Enkephalin immunoreactivity was observed in laminae I and II in slight amounts after 10 min, in moderate amounts after 30 minutes and very clearly after 60 min of the intrathecal injection of enkephalin antiserum. In addition, marked nonspecific staining was observed in the dorsal part but not in the ventral part of the white matter. These results indicate that antibodies injected intrathecally are capable of diffusing into the spinal cord within a time period of 10-60 min.