Developmental Changes in Expression of a Calcium-binding Protein (Spot 35-calbindin) in the Nervus Terminalis and the Vomeronasal and Olfactory Receptor Cells

Abstract

The detailed localization of spot 35-calbindin and its ontogenic change were studied in Nervus terminalis, the vomeronasal organ and the olfactory epithelium of the rat by immunohistochemistry. At the embryonic days 12 and 13 (E 12-13), calbindin-immunoreactive cells were found in the outermost layer of the presumptive olfactory bulb and within the olfactory placode. At E 14 to the postnatal day 1 (P 1), intense calbindin-immunoreactivity was localized in ganglionated fiber bundles of Nervus terminalis coursing through the mesenchymal spaces on both sides of the nasal septum. Nervus terminalis decreased the immunoreactivity abruptly after P 1 and it showed no distinct immunoreactivity for calbindin at P 7 and thereafter. On the other hand, numerous receptor cells in the olfactory epithelium and the thicker vomeronasal epithelium exhibited weak to moderate immunoreactivity for calbindin at E 18-P 1. Their immunoreactivity decreased in intensity progressively after P 7 and no distinct immunoreactivity for calbindin was detected in most of the receptor cells, whereas moderate immunoreactivity was detected in most of the vomeronasal and olfactory nerves at P 28 and P 63.

CaBPs and other immunohistochemical markers of the human vomeronasal system: A comparison with other mammals

“…It was reported that developmentally, rat VRNs showed CB-IR by embryonic day 18, but by postnatal day 7, there was a decrease in the number of immunoreactive VRNs and by 2 months postnatally only sporadic groups of VRNs were immunoreactive (Abe et al, 1992). However, this is in contrast to the findings of other laboratories demonstrating good-to-robust VRN-immunolabeling (Johnson et al, 1992;Kishimoto et al, 1993), and warrants further analysis.…”

“…On the other hand, VRNs of the rat (Abe et al, 1992;Johnson et al, 1992) and mouse (Kishimoto et al, 1993) appear to be CB-immunoreactive, as do the mouse vomeronasal nerve fibers in the nasal septum (Kishimoto et al, 1993). This indicates that CB-IR could at least be a candidate for identifying VRNs in IHC studies of the human VNO.…”

“…Also, in the VNO of a human infant, my colleagues and I concluded that the cells we observed displaying CB-LI were not VRNs (Johnson et al, 1994a), although the VRNs in other mammals do exhibit CB-IR (Abe et al, 1992;Johnson et al, 1992;Kishimoto et al, 1993).…”

“…In studies using rabbit polyclonal anti-CB antisera, CB has been immunolocalized to VRNs (Abe et al, 1992;Johnson et al, 1992;Kishimoto et al, 1993), and the vomeronasal nerve layer overlying and terminating within the AOB glomeruli (Celio, 1990). On the other hand, in one of these studies that also used a mouse monoclonal anti-CB antiserum , no CB-immunoreactivity (CB-IR) was detected in the vomeronasal nerve layer of the AOB (see Celio, 1990, fig.…”

“…CB IHC in the Human VNO Because of the evidence produced from our laboratory (Johnson et al, 1992) and other reports (Abe et al, 1992;Kishimoto et al, 1993) that in the mammalian VNO, CB-IR is specific for VRNs, and evidence that ORNs in the developing human exhibit CB-like immunoreactivity [CB-LI] (Johnson et al, 1995a), my colleagues and I examined CB-LI in the VNOs from a newborn and an adult human VNO (Johnson et al, 1994a). In this study, CB-like immunoreactive labeled columnar cells appeared to be randomly distributed around the lumen within both VNO epithelia (Fig.…”