PARVALBUMIN IMMUNOREACTIVITY IN THE TELENCEPHALIC HEMISPHERES OF THE TENCH, TINCA-TINCA

The distribution of parvalbumin immunoreactivity in the telencephalic hemispheres of the tench (Tinca tinca L.) was studied using a monoclon al antibody and the avidin-biotin immunoperoxidase method. A wide dist ribution of immunoreactive structures was found in both dorsal and ven tral areas of the telencephalic hemispheres. Normally, the parvalbumin -immunostained neurons in the dorsal area were smaller, more weakly st ained, and more scattered than those in the ventral one. In the dorsal area, parvalbumin-immunoreactivity was observed in practically all di visions. The highest density of positive somata was found in the later al nucleus. Density of stained fibres was generally low. Labelling in the ventral area appeared in the ventral and dorsal nuclei, with a hig h density of both immunoreactive fibres and cell bodies. Neurons were seen close to the ventricle, arranged in two groups of neurons with di fferent sizes and morphologies. The distribution and morphological cha racteristics of the parvalbuminergic cells were similar to those of pr eviously described GABAergic elements, suggesting a possible colocaliz ation of both substances in the teleost telencephalon, as it has been observed in different telencephalic areas of land vertebrates. On the other hand, significant differences were seen between the distribution of parvalbumin in the telencephalic hemispheres of the tench in compa rison with its distribution pattern in supposed homologous structures of the forebrain of amniotes.