Distribution of peptidergic populations in the human dentate gyrus (Somatostatin [SOM-28, SOM-12] and Neuropeptide Y [NPY]) during postnatal development

Abstract

The postnatal development of the human hippocampal formation establishes the time and place at which we start autobiographical memories. However, data concerning the maturation of the neurochemical phenotypes characteristic of interneurons in the human hippocampus are scarce. We have studied the perinatal and postnatal changes of the dentate gyrus (DG) interneuron populations at three rostrocaudal levels. Immunohistochemically identified neurons and fibers for somatostatin (SOM-12 and SOM-28) and neuropeptide Y (NPY) and the co-localization of SOM-28 and NPY were analyzed. In total, 13 cases were investigated from late pregnancy (1 case), perinatal period (6 cases), first year (1 case), early infancy (3 cases), and late infancy (2 cases). Overall, the pattern of distribution of these peptides in the DG was similar to that of the adult. The distribution of cells was charted, and the cell density (number of positive cells/mm(2)) was calculated. The highest density corresponded to the polymorphic cell layer and was higher at pre- and perinatal periods. At increasing ages, neuron density modifications revealed a decrease from 5 postnatal months onward. In contrast, by late infancy, two immunoreactive bands for SOM-28 and NPY in the molecular layer were much better defined. Double-immunohistochemistry showed that NPY-positive neurons co-localized with SOM-28, whereas some fibers contained only one or other of the neuropeptides. Thus, this peptidergic population, presumably inhibitory, probably has a role in DG maturation and its subsequent functional activity in memory processing.

Developmental study of vitamin C distribution in children's brainstems by immunohistochemistry

“…Previous works (Ramos-Vara, 2005;Liu et al, 2010) reported that the use of retrieval-antigen systems can recover the loss of immunolabeling, thus we have performed a protocol that includes the retrieval of antigens by strong alkaline treatment (Guntern et al, 1989). This protocol has been successfully used by our group for detection of neuropeptides and proteins in the same human brains (Graterón et al, 2003;Insausti et al, 2010;Coveñas et al, 2014;Cebada-Sánchez et al, 2014), providing a good morphological preservation of the tissue. Due to the fact that a specific distribution pattern of Vit C immunolabeling is not clearly stated regarding the gender or the cause of death, it seems that the influence of both parameters on the results found here can be discarded.…”

“…This could be due to an earlier myelination process in lifetime in the brainstem than in other brain regions, then variation in volume due to fixation could be minimal. The influence of myelination process and changes in brain volume on neuronal density after immunohistochemical detection of several neuropeptides has been discussed previously by Cebada-Sánchez et al (2014).…”

“…The protocol applied here has been previously validated for the detection of calcium-binding proteins (Graterón et al, 2003), neuropeptides such as somatostatin and neuropeptide Y (Cebada-Sánchez et al, 2014), and for the mapping of HIF-1␣ and MAP-2 (Coveñas et al, 2014) in the brains of the same cases studied here. The highly specific polyclonal primary antibody against Vit C (GEMAC S. A., Saint Jean d'Illac, France; reference: AP-131) was developed in rats and was diluted 1/500, and incubations with Table 1 List of the cases considered for this study.…”

“…As previously described (Cebada-Sánchez et al, 2014;Coveñas et al, 2014), brains were immediately immersion-fixed in 10% formalin after dissection and then transferred to 4% paraformaldehyde in 0.1 M phosphate buffer-saline (PBS), pH 7.4, following the standardized protocol carried out in our Laboratory (Insausti et al, 2010). Brainstems were dissected out and cryoprotected in increasing sucrose solutions (15-30% in PBS) until they sank.…”

Vitamin transporters in mice brain with aging

“…; Cebada‐Sanchez et al. ). Single IHC reactions were performed after peroxidase activity was reduced using methanol and hydrogen peroxide (2 : 1).…”