Eur J Anat, 5 (3): 113-117 (2001)

Immunoreactivity for GABA in the retina of the chameleon (Chamaeleo chamaeleon)

Bennis M., Armengol J.A.

División de Neurociencias, LAB, CSIC-UPO, Ctra. Utrera, km 1, E-41013 Sevilla, Spain

ABSTRACT Antibodies directed against gamma-aminobutyric (GABA) and L-glutamic acid decarboxylase (GAD) were used to study the GABAergic cell populations of the chameleon retina. GABA immunoreactivity was found in the two main retinal interneurons: amacrine and horizontal cells. Amacrine, displaced amacrine, intra- and interplexiform cells displayed the strongest GABA-immunoreactivity of the retinal cell types. Horizontal cells formed a continuous GABA-immunoreactive cell layer lying in the outermost portion of the inner nuclear layer. In contrast with previous studies, describing the absence of horizontal GABAergic cells in the chameleon retina, the present results demonstrated that the vast majority of horizontal cells of the chameleon retina possess GABA, and agree with the key role that GABAergic synaptic transmission plays in the outer plexiform layer of the vertebrate retina.

Keywords: 4 aminobutyric acid, antibody, glutamate decarboxylase, animal tissue, article, chameleon, immunoreactivity, interneuron, nonhuman, reptile, retina, retina amacrine cell, synaptic transmission