Expression of calbindin-D28k and parvalbumin during development of rat's basolateral amygdaloid complex

Parvalbumin and calbindin-D28k are calcium-binding proteins. which are cons idered to be markers for certain populations of GABAergic neurons. Their co rrect development in the basolateral amygdaloid complex is critical for the proper emotional functioning in adult live of human and animals. Therefore . in this paper we describe the pattern of the morphological differentiatio n and distribution of immunoreactive elements of the parvalbumin and calbin din-D28k in this complex on the basis of immunohistochemically stained mate rial obtained from embryonic (E20) and postnatal (P0-P90) rat brains. Calbindin-D28k appeared early in the development, already in the prenatal l ife. At this time immunopositive reaction was visible only in cell bodies. However, during development the population of immunopositive neurons was di vided into four types: iii polygonal; (2) piriform-like; (3) bipolar; and ( 4) pyramidal-like. Two weeks after birth calbindin-D28k immunoreactivity al so appeared in neuropil. First, there were visible calbindin-D28k positive fibers and granules that encircled unstained cell bodies and formed basket- like structures. Subsequently, these granules appeared along proximal parts of unstained dendrites forming, so called 'cartridges'. The distribution o f calbindin-D28k positive cells during postnatal life was rather homogenous throughout whole basolateral complex. Intensity of calbindin-D28k immunore activity reached mature level on the 21st day after birth. The maturation pattern of parvalbumin immunopositive elements followed the same sequence as calbindin-D28k, but it started much later - since the 17th day after birth and reached mature appearance on the 30th day of life. Con trary to calbindin-D28k, palvalbumin was not homogeneously distributed in t he basolateral complex. Originally, parvalbumin was restricted to the magno cellular part of basolateral nucleus but it was finally expressed also in t he parvicellular part of basolateral nucleus and the dorsolateral part of l ateral nucleus. The differences in development of these two calcium-binding proteins indica te that parvalbumin and calbindin-D28k play diverse roles during developmen t and maturation of the basolateral amygdala. (C) 2000 ISDN. Published by E lsevier Science Ltd. All rights reserved.