Localisation of GABA-immunopositive cells in the river lamprey spinal cord

Using the immunohistochemical PAP method GABA-immunopositive cells were revealed in horizontal and transverse sections of lamprey spinal cord. The most numerous intensively stained small oval cells were located in the dorsal part of the spinal cord. The larger cells with 2-3 long nonbranching processes were located at the border of lateral column, the main part of which is composed of GABA-immunonegative cells. Some of the largest, but less intensively stained cells were observed in the lateral part of the spinal cord beyond the cell column and in the ventrolateral corner of transverse sections. The latter are identified as previously described edge cells. Functional identification of the remaining GABA-immunopositive cells is rather difficult. Some of them may be glial elements.