Distribution of parvalbumin-, calretinin-, and calbindin-D28k-immunoreactive neurons and fibers in the human entorhinal cortex

Abstract

Parvalbumin, calretinin, and calbindin-D28k are calcium-binding proteins that are located in largely nonoverlapping neuronal populations in the brain. The authors studied the distribution of parvalbumin-, calretinin-, and calbindin-D28k-immunoreactive (ir) cells, fibers, terminals, and neuropil in the eight subfields of the human entorhinal cortex. The distribution of each of the three calcium-binding proteins largely followed the cytoarchitectonic borders of the eight entorhinal subfields, although the regional and laminar distributions of the three proteins were segregated rather than overlapping. The highest density of parvalbumin-ir neurons and terminals was found in the caudal and lateral subfields of the entorhinal cortex. Calretinin and calbindin-D28k immunoreactivities were high rostromedially, although a large number of calretinin and calbindin-D28k neurons were also found in the caudal subfields. All parvalbumin-ir cells had a morphological appearance of nonpyramidal neurons. Parvalbumin-ir terminals formed basket-like formations around unstained somata and cartridges, suggesting that parvalbumin neurons compose a subpopulation of gamma-aminobutyric acid (GABA)ergic basket cells and chandelier cells, respectively. Although calretinin and calbindin-D28k were also found in numerous nonpyramidal neurons, both were also located in pyramidal-shaped neurons in layers V and VI (calretinin) and in layers II and III (calbindin) of the entorhinal cortex, suggesting that they play roles in projection neurons as well. Moreover, the high density of nonpyramidal neurons containing calcium-binding proteins in layers II and III of the entorhinal cortex suggests that they form an integral component of a network that controls the entorhinal outputs to the hippocampus. Furthermore, the largely nonoverlapping distributions of the parvalbumin-, calretinin-, and calbindin-ir neuronal populations in the entorhinal cortex indicate that each of them may modulate a different subset of topographically organized entorhinal outputs.

Subpopulations of neurons expressing parvalbumin in the human amygdala

“…2L). Light microscopy analysis showed that the distribution patterns of PVB, CB, and PNNs staining in our tissue correspond well to those detected in the human and monkey amygdala and entorhinal cortex in other laboratories (Hartig et al, 1995;Sorvari et al, 1995Sorvari et al, ,1996bMikkonen et al, 1997). Standard tests for antisera specificity included omission of either the primary or the secondary antisera.…”

Immunoreactivity of the calbindin D28k in the parahippocampal gyrus of chinchilla

“…The CB immunoreactivity was observed in pyramidal and non-pyramidal neurons of all areas of the examined structure in chinchilla, similarly as in human (7), macaque (17), and mouse (25). CB-positive reaction was observed in multiform neurons like in human (7), macaque (17), and mouse (25). Weak immunoreactivity was demonstrated in pyramidal shaped cells, and moderate and intensive immunoreactivity in multipolar, bipolar, Cajal-Retzius, as well as in round neurons similarly as in human (7) and macaque (17).…”

“…The CB immunoreactivity was observed in pyramidal and non-pyramidal neurons of all areas of the examined structure in chinchilla, similarly as in human (7), macaque (17), and mouse (25). CB-positive reaction was observed in multiform neurons like in human (7), macaque (17), and mouse (25).…”

“…CB-positive reaction was observed in multiform neurons like in human (7), macaque (17), and mouse (25). Weak immunoreactivity was demonstrated in pyramidal shaped cells, and moderate and intensive immunoreactivity in multipolar, bipolar, Cajal-Retzius, as well as in round neurons similarly as in human (7) and macaque (17). Distribution of pyramidal neurons with weak CB immunoreactivity in PG in the chinchilla, human (7), and mouse (25) may suggest that they are primary projection neurons.…”

“…Important research is conducted to specify distribution and colocalisation of this protein in order to explain functions and processes occurring in neurons in the pathogenesis of many CNS diseases. Until now, the immunoreactivity to CB have been localised in neurons of the mammalian enteric nervous system (3) and CNS (1, 4-6, 12, 22, 28), including GP in human (7), monkey (17), and mouse (25). In our previous research, CB expression in some CNS areas of chinchilla was presented (12,13,28).…”