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Neurohypophysial Hormones Regulate Amphibious Behaviour in the Mudskipper Goby.

Sakamoto T, Nishiyama Y, Ikeda A, Takahashi H, Hyodo S, Kagawa N, Sakamoto H - PLoS ONE (2015)

Bottom Line: Here, we examined the effects of arginine vasotocin and isotocin administration on the amphibious behavior of individual mudskippers in vivo.The 'frequency of migration' was decreased after ICV injection of arginine vasotocin or isotocin, reflecting a tendency to remain in the water.ICV injections of isotocin receptor antagonist with arginine vasotocin or isotocin inhibited all of these hormonal effects.

View Article: PubMed Central - PubMed

Affiliation: Ushimado Marine Institute, Faculty of Science, Okayama University, Ushimado, Setouchi, 701-4303, Japan.

ABSTRACT
The neurohypophysial hormones, arginine vasotocin and isotocin, regulate both hydromineral balance and social behaviors in fish. In the amphibious mudskipper, Periophthalmus modestus, we previously found arginine-vasotocin-specific regulation of aggressive behavior, including migration of the submissive subordinate into water. This migration also implies the need for adaptation to dehydration. Here, we examined the effects of arginine vasotocin and isotocin administration on the amphibious behavior of individual mudskippers in vivo. The mudskippers remained in the water for an increased period of time after 1-8 h of intracerebroventricular (ICV) injection with 500 pg/g arginine vasotocin or isotocin. The 'frequency of migration' was decreased after ICV injection of arginine vasotocin or isotocin, reflecting a tendency to remain in the water. ICV injections of isotocin receptor antagonist with arginine vasotocin or isotocin inhibited all of these hormonal effects. In animals kept out of water, mRNA expression of brain arginine vasotocin and isotocin precursors increased 3- and 1.5-fold, respectively. Given the relatively wide distribution of arginine vasotocin fibres throughout the mudskipper brain, induction of arginine vasotocin and isotocin under terrestrial conditions may be involved also in the preference for an aquatic habitat as ligands for brain isotocin receptors.

No MeSH data available.


Related in: MedlinePlus

Arginine-vasotocin- (VT) and isotocin- (IT) immunoreactivities in the paraventricular preoptic nucleus (PP) of the hypothalamus.Intense VT- (red) and IT- (green) immunoreactivities were observed in the somata and proximal dendrites of relatively large neurones in transverse sections. Histology of the PP was visualized by blue fluorescent Nissl staining.
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pone.0134605.g007: Arginine-vasotocin- (VT) and isotocin- (IT) immunoreactivities in the paraventricular preoptic nucleus (PP) of the hypothalamus.Intense VT- (red) and IT- (green) immunoreactivities were observed in the somata and proximal dendrites of relatively large neurones in transverse sections. Histology of the PP was visualized by blue fluorescent Nissl staining.

Mentions: To assess possible brain regions involved in regulation of amphibious behaviour by neurohypophysial hormones, we examined the localisation and distribution of VT- and IT-immunoreactive cells in the brain, spinal cord, and pituitary of adult mudskippers. As shown schematically (Fig 6), VT- and IT-immunoreactive cell bodies or fibres were found in several telencephalic, diencephalic, mesencephalic, and rhombencephalic regions in the mudskipper brain. In the diencephalon, intense VT (red) and IT (green) immunoreactivities were observed in the somata and proximal dendrites of relatively large (magnocellular) neurones and in those of small sized (parvocellular) neurones in the paraventricular preoptic nucleus (PP) of the hypothalamus (Fig 7). The number of immunoreactive neurones and the density of immunoreactive fibres appeared to be greater for VT (Fig 7A) compared to IT (Fig 7B); the histology of the PP was visualized in blue by fluorescent Nissl staining (Fig 7A and 7B). Dual immunofluorescent analyses in sagittal sections revealed VT- (red) and IT- (green) immunoreactive cell bodies and fibres in several brain regions (Fig 8). The immunoreactive magnocellular neurons were mainly observed in the dorsal part of the PP (PPd), and the parvocellular neurons in the ventral part (PPv). In particular, in the PPd, large somata of VT- and IT-immunoreactive neurones were present in each population (Fig 8A; arrows). Conversely, IT immunoreactivities were seen in some VT-immunoreactive neurons in the PPv (Fig 8A; arrowheads). Small neurones with VT- and IT-immunoreactivities were also found in the ventral hypothalamic area (around the pars tuberalis) (Fig 8B; arrowheads), and the characteristics of these immunoreactive neurones appeared similar to those of the parvocellular part of PP (Fig 8A and 8B; arrowheads). The dense projections of VT- and IT-immunoreactive fibres were present in the ventral part of the hypothalamus and extended into the pars nervosa of the pituitary (Fig 8B). Most of the immunoreactive fibres in the hypothalamus were found at similar distributions for VT and IT and corresponded to projections from the PP, but their fibres somewhat differed in the populations (Fig 8B).


Neurohypophysial Hormones Regulate Amphibious Behaviour in the Mudskipper Goby.

Sakamoto T, Nishiyama Y, Ikeda A, Takahashi H, Hyodo S, Kagawa N, Sakamoto H - PLoS ONE (2015)

Arginine-vasotocin- (VT) and isotocin- (IT) immunoreactivities in the paraventricular preoptic nucleus (PP) of the hypothalamus.Intense VT- (red) and IT- (green) immunoreactivities were observed in the somata and proximal dendrites of relatively large neurones in transverse sections. Histology of the PP was visualized by blue fluorescent Nissl staining.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4521927&req=5

pone.0134605.g007: Arginine-vasotocin- (VT) and isotocin- (IT) immunoreactivities in the paraventricular preoptic nucleus (PP) of the hypothalamus.Intense VT- (red) and IT- (green) immunoreactivities were observed in the somata and proximal dendrites of relatively large neurones in transverse sections. Histology of the PP was visualized by blue fluorescent Nissl staining.
Mentions: To assess possible brain regions involved in regulation of amphibious behaviour by neurohypophysial hormones, we examined the localisation and distribution of VT- and IT-immunoreactive cells in the brain, spinal cord, and pituitary of adult mudskippers. As shown schematically (Fig 6), VT- and IT-immunoreactive cell bodies or fibres were found in several telencephalic, diencephalic, mesencephalic, and rhombencephalic regions in the mudskipper brain. In the diencephalon, intense VT (red) and IT (green) immunoreactivities were observed in the somata and proximal dendrites of relatively large (magnocellular) neurones and in those of small sized (parvocellular) neurones in the paraventricular preoptic nucleus (PP) of the hypothalamus (Fig 7). The number of immunoreactive neurones and the density of immunoreactive fibres appeared to be greater for VT (Fig 7A) compared to IT (Fig 7B); the histology of the PP was visualized in blue by fluorescent Nissl staining (Fig 7A and 7B). Dual immunofluorescent analyses in sagittal sections revealed VT- (red) and IT- (green) immunoreactive cell bodies and fibres in several brain regions (Fig 8). The immunoreactive magnocellular neurons were mainly observed in the dorsal part of the PP (PPd), and the parvocellular neurons in the ventral part (PPv). In particular, in the PPd, large somata of VT- and IT-immunoreactive neurones were present in each population (Fig 8A; arrows). Conversely, IT immunoreactivities were seen in some VT-immunoreactive neurons in the PPv (Fig 8A; arrowheads). Small neurones with VT- and IT-immunoreactivities were also found in the ventral hypothalamic area (around the pars tuberalis) (Fig 8B; arrowheads), and the characteristics of these immunoreactive neurones appeared similar to those of the parvocellular part of PP (Fig 8A and 8B; arrowheads). The dense projections of VT- and IT-immunoreactive fibres were present in the ventral part of the hypothalamus and extended into the pars nervosa of the pituitary (Fig 8B). Most of the immunoreactive fibres in the hypothalamus were found at similar distributions for VT and IT and corresponded to projections from the PP, but their fibres somewhat differed in the populations (Fig 8B).

Bottom Line: Here, we examined the effects of arginine vasotocin and isotocin administration on the amphibious behavior of individual mudskippers in vivo.The 'frequency of migration' was decreased after ICV injection of arginine vasotocin or isotocin, reflecting a tendency to remain in the water.ICV injections of isotocin receptor antagonist with arginine vasotocin or isotocin inhibited all of these hormonal effects.

View Article: PubMed Central - PubMed

Affiliation: Ushimado Marine Institute, Faculty of Science, Okayama University, Ushimado, Setouchi, 701-4303, Japan.

ABSTRACT
The neurohypophysial hormones, arginine vasotocin and isotocin, regulate both hydromineral balance and social behaviors in fish. In the amphibious mudskipper, Periophthalmus modestus, we previously found arginine-vasotocin-specific regulation of aggressive behavior, including migration of the submissive subordinate into water. This migration also implies the need for adaptation to dehydration. Here, we examined the effects of arginine vasotocin and isotocin administration on the amphibious behavior of individual mudskippers in vivo. The mudskippers remained in the water for an increased period of time after 1-8 h of intracerebroventricular (ICV) injection with 500 pg/g arginine vasotocin or isotocin. The 'frequency of migration' was decreased after ICV injection of arginine vasotocin or isotocin, reflecting a tendency to remain in the water. ICV injections of isotocin receptor antagonist with arginine vasotocin or isotocin inhibited all of these hormonal effects. In animals kept out of water, mRNA expression of brain arginine vasotocin and isotocin precursors increased 3- and 1.5-fold, respectively. Given the relatively wide distribution of arginine vasotocin fibres throughout the mudskipper brain, induction of arginine vasotocin and isotocin under terrestrial conditions may be involved also in the preference for an aquatic habitat as ligands for brain isotocin receptors.

No MeSH data available.


Related in: MedlinePlus