Spatial learning induces increasing of argyrophilic nucleolar organizer region (AgNOR) of pallium medial neurons in toads (Rhinella arenarum)

DANERI, M. F., PUDDINGTON, M. M. & MUZIO, R. N.

Huerta Grande, Córdoba

Congreso; XXVII Congreso Anual de la Sociedad Argentina de Investigación en Neurociencia (SAN); 2012

Sociedad Argentina de Investigación en Neurociencia (SAN)

Spatial learning and memory related morphological changes in the argyrophilic nucleolar organizer region (AgNOR) of telencephalic neurons in the toad Rhinella arenarum were quantitatively evaluated by means of AgNOR neurohistochemical stain. The AgNORs and nuclei of nerve cells of four different telencephalic regions of toads trained in a spatial task or submitted to a similar non-contingent spatial procedure (control group) were morphometrically evaluated. Results show that relative area of AgNORs in neurons of the medial pallium (homologue to the mammalian hippocampus) increased significantly in the spatial learning group, but not in control group. This effect seems to be highly specific as it did not appear in the medial pallium area of the control group neither in septum, striatum nor amygdala of both groups. As the size of AgNORs in the nerve cell nuclei reflects the level of transcriptive activity, these morphological changes could be revealing increased protein synthesis related with learning and memory. These findings contribute to locate the subregions of the amphibian telencephalon linked to spatial learning and also indicate that the AgNOR staining technique would be a useful tool in assessing learning and memory related neuronal activity in toads.