Calbindin‐D28k, calretinin, and S‐100 immunoreactivities in rat pineal gland during postnatal development

Abstract

Profound morphological modifications occur during postnatal development of the rat pineal gland. We have immunohistochemically followed those events from postnatal day 1 to 20 by using three cytoarchitectonic markers (S-100, calbindin-D28k, and calretinin) that belong to the calmodulin/troponin C calcium-binding protein family. In the developing rat pineal, anticalbindin-D28k antibody labels three cell types: immature and mature astrocytes and perivascular type II pinealocytes. During development, calbindin-D28k positive cells migrate from the base of the pineal stalk into the superficial part of the pineal. Calbindin-D28k, usually used as a neuronal marker in the central nervous system, recognizes in rat pineal precursor astrocytes 5 days before S-100 and labels a subpopulation somewhat different from S-100 positive astrocytes. Calretinin immunoreactivity appeared in the postero-superior part of the pineal and was abundant until postnatal day 5, then its density dramatically felt to leave, after postnatal day 20, an occasional population of cells whose morphology is compatible with neuron-like cells.

Immunofluorescence reveals unusual patterns of labelling for connexin43 localized to calbindin‐D28K‐positive interstitial cells in the pineal gland

“…The striking localization of Cx43 largely in perivascular spaces in the pineal, and specifically localization to Nissl‐stained cells that lacked labelling for TrypH, and that were concentrated near vascular elements prompted us to examine other cytochemically identified cell types occupying these spaces. One such cell population is represented by expression of the calcium‐binding protein calbindin, immunolabelling of which has been reported in the pineal gland in a variety of species (Roman et al ., ; Yamamoto et al ., ; Bastianelli & Pochet, , ; Karan & Timurkaan, ). We first sought to confirm and/or clarify the characteristics of this population compared with other pineal cell types.…”

Impact of Cytoplasmic Calcium Buffering on the Spatial and Temporal Characteristics of Intercellular Calcium Signals in Astrocytes

“…Endogenous buffering proteins such as calbindin-D28K and its glucose-related forms have been shown to be distributed in both neurons (Kohr et al, 1991) and astrocytes (Bastianelli and Pochet, 1995). Increased expression of mRNA encoding these proteins was detected after acute kainic acid-induced seizure, global ischemia, and brain trauma (L oewenstain et al, 1994) and also in genetically epilepsy-prone rats (Montiel et al, 1994).…”

Glucocorticoids?potent modulators of astrocytic calcium signaling

“…Calreticulin appears to locate to the nucleus from the cytosol by virtue of its interaction with the GR (Roderick et al, 1997). The effect of glucocorticoids on other endogenous calcium buffering proteins expressed by astrocytes, such as calbinding-D28K and its glucose related forms (Bastianelli and Pochet, 1995), remains to be established.…”