Postnatal development of the Ca2+ -binding proteins parvalbumin and calbindin D-28k containing neurons in the rat amygdala-An Immunohistochemical Study

Chung, Yoon Young; Hu, Young; Yun, Sang Pil; Chang, In Youb; Kim, Jong Joong; Moon, Jeong Seok

Abstract

The maturation pattern of the calcium binding proteins parvalbumin (PV) and calbindin-D28K (CB) from the day of birth, postnatal day 0 (P0) to 30 days (P5, P10, P15, P20, P30) and adult was studied in the rat amygdala using immunohistochemistry. PV and CB immunoreactivities in the amygdala of the rat showed very different patterns during postnatal development. The first PV-immunoreactive neurons appeared in the cortical amygdaloid nuclei and the basolateral amygdaloid nucleus at P5, and then in the lateral amygdaloid nucleus and the basomedial amygdaloid nucleus at P10. Adult patterns of PV-immunoreactive neurons were reached at P20. In contrast, CB-immunoreactive neurons were already found at birth in all amygdaloid nuclei except the intercalated nucleus. The intensity and number of immunoreactivity of CB-containing neurons increased during the first 10 days of postnatal life but dramatically decreased at P15. Mature patterns CB-immunoreactive neurons were achieved at P20. These two calcium binding proteins exhibited a non-homogeneous distribution in the adult amygdala, PV-immunoreactive neurons were mainly localized in the basolateral nuclear group but not in the medial amygdaloid nucleus, the cental amygdaloid nucleus and the intercalated nucleus. In contrast, CB-immunoreactive neurons were distributed in almost all amygdaloid nuclei except the intercalated nucleus. The present results showing different postnatal maturation patterns such as time of appearance, the number and distribution of immunoreactive cells suggest that PV and CB may play a different functional role during the postnatal development of the amygdala.