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Interactions with the young down-regulate adult olfactory neurogenesis and enhance the maturation of olfactory neuroblasts in sheep mothers.

Brus M, Meurisse M, Keller M, Lévy F - Front Behav Neurosci (2014)

Bottom Line: In addition, a morphological analysis was performed by measuring the dendritic arbor of neuroblasts in both structures.We showed that the postpartum period was associated with a decrease in olfactory and hippocampal adult neurogenesis.Our assumption is that fewer new neurons decrease cell competition in the olfactory bulb and enhance maturation of those new neurons selected to participate in the learning of the young odor.

View Article: PubMed Central - PubMed

Affiliation: INRA, UMR 85, Physiologie de la Reproduction et des Comportements Nouzilly, France ; CNRS, UMR 7247 Nouzilly, France ; Université François Rabelais Tours, France ; IFCE Nouzilly, France.

ABSTRACT
New neurons are continuously added in the dentate gyrus (DG) and the olfactory bulb of mammalian brain. While numerous environmental factors controlling survival of newborn neurons have been extensively studied, regulation by social interactions is less documented. We addressed this question by investigating the influence of parturition and interactions with the young on neurogenesis in sheep mothers. Using Bromodeoxyuridine, a marker of cell division, in combination with markers of neuronal maturation, the percentage of neuroblasts and new mature neurons in the olfactory bulb and the DG was compared between groups of parturient ewes which could interact or not with their lamb, and virgins. In addition, a morphological analysis was performed by measuring the dendritic arbor of neuroblasts in both structures. We showed that the postpartum period was associated with a decrease in olfactory and hippocampal adult neurogenesis. In the olfactory bulb, the suppressive effect on neuroblasts was dependent on interactions with the young whereas in the DG the decrease in new mature neurons was associated with parturition. In addition, dendritic length and number of nodes of neuroblasts were significantly enhanced by interactions with the lamb in the olfactory bulb but not in the DG. Because interactions with the young involved learning of the olfactory signature of the lamb, we hypothesize that this learning is associated with a down-regulation in olfactory neurogenesis and an enhancement of olfactory neuroblast maturation. Our assumption is that fewer new neurons decrease cell competition in the olfactory bulb and enhance maturation of those new neurons selected to participate in the learning of the young odor.

No MeSH data available.


Related in: MedlinePlus

Effects of parturition and/or interactions with the young on the proportion of neuroblasts and mature neurons. Percentage of neuroblasts (BrdU+/DCX+) and new mature neurons (BrdU+/NeuN+) in the granular layer of the MOB (A–B) and in the granular cell layer of the DG (C–D), in the “Virgin” (n = 6), the “No Lamb” (n = 6) and the “With Lamb” (n = 5) groups. Data are expressed as percentage of BrdU+ cells colabeled with NeuN (B–D) and DCX (A–C). In the MOB, only the proportion of BrdU+/DCX+ cells in the “With Lamb” group significantly differed from the two other groups (A). In the DG, only the proportion of BrdU+/NeuN+ cells in both parturient groups is significantly lower than the “Virgin” group (D). (E–H) High magnification of confocal images of fluorescent immunolabeling depicting colocalization of BrdU+/NeuN+ (F, H) and BrdU+/DCX+ (E, G) in the granular layer of the MOB (E–F), in the granular cell layer of the DG (G–H). Cell nuclei are labeling with Hoechst. Scales bars: 10 µm. MOB: main olfactory bulb, DG: dentate gyrus, BrdU: bromodeoxyuridine, DCX: doublecortin, NeuN: neuronal nuclei. * p ≤ 0.05, ** p < 0.01.
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Figure 3: Effects of parturition and/or interactions with the young on the proportion of neuroblasts and mature neurons. Percentage of neuroblasts (BrdU+/DCX+) and new mature neurons (BrdU+/NeuN+) in the granular layer of the MOB (A–B) and in the granular cell layer of the DG (C–D), in the “Virgin” (n = 6), the “No Lamb” (n = 6) and the “With Lamb” (n = 5) groups. Data are expressed as percentage of BrdU+ cells colabeled with NeuN (B–D) and DCX (A–C). In the MOB, only the proportion of BrdU+/DCX+ cells in the “With Lamb” group significantly differed from the two other groups (A). In the DG, only the proportion of BrdU+/NeuN+ cells in both parturient groups is significantly lower than the “Virgin” group (D). (E–H) High magnification of confocal images of fluorescent immunolabeling depicting colocalization of BrdU+/NeuN+ (F, H) and BrdU+/DCX+ (E, G) in the granular layer of the MOB (E–F), in the granular cell layer of the DG (G–H). Cell nuclei are labeling with Hoechst. Scales bars: 10 µm. MOB: main olfactory bulb, DG: dentate gyrus, BrdU: bromodeoxyuridine, DCX: doublecortin, NeuN: neuronal nuclei. * p ≤ 0.05, ** p < 0.01.

Mentions: The proportion of newborn neurons was measured in each group by using a double immunofluorescent labeling for BrdU and NeuN, a marker of post-mitotic neurons, and DCX, a marker of neuroblasts (Figures 3E–H). In the granular layer of the MOB, only the proportion of BrdU+/DCX+ cells significantly differed between groups (H = 8.27, p = 0.02; Figure 3A). This proportion was significantly lower in the “With Lamb” group compared to the “Virgin” or the “No Lamb” groups (“With Lamb” vs. “Virgin” or “No Lamb” groups: U = 2.47, p = 0.01; Figure 3A). The proportion of new post-mitotic neurons (BrdU/NeuN+ cells) did not differ between groups (H = 1.23, p = 0.5; Figure 3B).


Interactions with the young down-regulate adult olfactory neurogenesis and enhance the maturation of olfactory neuroblasts in sheep mothers.

Brus M, Meurisse M, Keller M, Lévy F - Front Behav Neurosci (2014)

Effects of parturition and/or interactions with the young on the proportion of neuroblasts and mature neurons. Percentage of neuroblasts (BrdU+/DCX+) and new mature neurons (BrdU+/NeuN+) in the granular layer of the MOB (A–B) and in the granular cell layer of the DG (C–D), in the “Virgin” (n = 6), the “No Lamb” (n = 6) and the “With Lamb” (n = 5) groups. Data are expressed as percentage of BrdU+ cells colabeled with NeuN (B–D) and DCX (A–C). In the MOB, only the proportion of BrdU+/DCX+ cells in the “With Lamb” group significantly differed from the two other groups (A). In the DG, only the proportion of BrdU+/NeuN+ cells in both parturient groups is significantly lower than the “Virgin” group (D). (E–H) High magnification of confocal images of fluorescent immunolabeling depicting colocalization of BrdU+/NeuN+ (F, H) and BrdU+/DCX+ (E, G) in the granular layer of the MOB (E–F), in the granular cell layer of the DG (G–H). Cell nuclei are labeling with Hoechst. Scales bars: 10 µm. MOB: main olfactory bulb, DG: dentate gyrus, BrdU: bromodeoxyuridine, DCX: doublecortin, NeuN: neuronal nuclei. * p ≤ 0.05, ** p < 0.01.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC3927075&req=5

Figure 3: Effects of parturition and/or interactions with the young on the proportion of neuroblasts and mature neurons. Percentage of neuroblasts (BrdU+/DCX+) and new mature neurons (BrdU+/NeuN+) in the granular layer of the MOB (A–B) and in the granular cell layer of the DG (C–D), in the “Virgin” (n = 6), the “No Lamb” (n = 6) and the “With Lamb” (n = 5) groups. Data are expressed as percentage of BrdU+ cells colabeled with NeuN (B–D) and DCX (A–C). In the MOB, only the proportion of BrdU+/DCX+ cells in the “With Lamb” group significantly differed from the two other groups (A). In the DG, only the proportion of BrdU+/NeuN+ cells in both parturient groups is significantly lower than the “Virgin” group (D). (E–H) High magnification of confocal images of fluorescent immunolabeling depicting colocalization of BrdU+/NeuN+ (F, H) and BrdU+/DCX+ (E, G) in the granular layer of the MOB (E–F), in the granular cell layer of the DG (G–H). Cell nuclei are labeling with Hoechst. Scales bars: 10 µm. MOB: main olfactory bulb, DG: dentate gyrus, BrdU: bromodeoxyuridine, DCX: doublecortin, NeuN: neuronal nuclei. * p ≤ 0.05, ** p < 0.01.
Mentions: The proportion of newborn neurons was measured in each group by using a double immunofluorescent labeling for BrdU and NeuN, a marker of post-mitotic neurons, and DCX, a marker of neuroblasts (Figures 3E–H). In the granular layer of the MOB, only the proportion of BrdU+/DCX+ cells significantly differed between groups (H = 8.27, p = 0.02; Figure 3A). This proportion was significantly lower in the “With Lamb” group compared to the “Virgin” or the “No Lamb” groups (“With Lamb” vs. “Virgin” or “No Lamb” groups: U = 2.47, p = 0.01; Figure 3A). The proportion of new post-mitotic neurons (BrdU/NeuN+ cells) did not differ between groups (H = 1.23, p = 0.5; Figure 3B).

Bottom Line: In addition, a morphological analysis was performed by measuring the dendritic arbor of neuroblasts in both structures.We showed that the postpartum period was associated with a decrease in olfactory and hippocampal adult neurogenesis.Our assumption is that fewer new neurons decrease cell competition in the olfactory bulb and enhance maturation of those new neurons selected to participate in the learning of the young odor.

View Article: PubMed Central - PubMed

Affiliation: INRA, UMR 85, Physiologie de la Reproduction et des Comportements Nouzilly, France ; CNRS, UMR 7247 Nouzilly, France ; Université François Rabelais Tours, France ; IFCE Nouzilly, France.

ABSTRACT
New neurons are continuously added in the dentate gyrus (DG) and the olfactory bulb of mammalian brain. While numerous environmental factors controlling survival of newborn neurons have been extensively studied, regulation by social interactions is less documented. We addressed this question by investigating the influence of parturition and interactions with the young on neurogenesis in sheep mothers. Using Bromodeoxyuridine, a marker of cell division, in combination with markers of neuronal maturation, the percentage of neuroblasts and new mature neurons in the olfactory bulb and the DG was compared between groups of parturient ewes which could interact or not with their lamb, and virgins. In addition, a morphological analysis was performed by measuring the dendritic arbor of neuroblasts in both structures. We showed that the postpartum period was associated with a decrease in olfactory and hippocampal adult neurogenesis. In the olfactory bulb, the suppressive effect on neuroblasts was dependent on interactions with the young whereas in the DG the decrease in new mature neurons was associated with parturition. In addition, dendritic length and number of nodes of neuroblasts were significantly enhanced by interactions with the lamb in the olfactory bulb but not in the DG. Because interactions with the young involved learning of the olfactory signature of the lamb, we hypothesize that this learning is associated with a down-regulation in olfactory neurogenesis and an enhancement of olfactory neuroblast maturation. Our assumption is that fewer new neurons decrease cell competition in the olfactory bulb and enhance maturation of those new neurons selected to participate in the learning of the young odor.

No MeSH data available.


Related in: MedlinePlus