Expression of gamma-aminobutyric acid and calcium binding protein-parvalbumin by chick motoneurons.

The expression of calcium binding protein parvalbumin (PV) and gamma-aminobutyric acid (GABA) was studied in the chick motoneurons by using pre- and postembedding immunocytochemistry. Our data reveal that PV and GABA are colocalized in the majority, but not all, of chick lumbo-sacral spinal motoneurons innervating the somatic muscles. It is suggested that, in this neuromuscular system, GABA does not act as a classical inhibitory neurotransmitter but, combined with calcium, could be involved, at least in part, in the maintenance of neurons and the prevention of cell death as in certain neurodegenerative disorders.