Immunocytochemical studies of vasotocin and mesotocin in the hypothalamo-hypophysial system of the chicken

Tennyson, Virginia M.; Hou-Yu, Anna; Nilaver, Gajanan; Zimmerman, Earl A.

doi:10.1007/bf00218005

Cited by 45 publications

(19 citation statements)

References 22 publications

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“…The lack of a contribution of Pa neurons to the hypothalamo-neurohypophysial tract in the echidna might represent a primitive condition or could have developed after divergence from therians. The presence of many NPH-and vasotocin-immunoreactive neurons in a paraventricular position in the avian hypothalamus [Peczély and Antoni, 1984;Tennyson et al, 1985] supports the latter proposition.…”

Section: Course and Origin Of The Hypothalamoneurohypophysial Tractsupporting

confidence: 61%

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The Hypothalamic Supraoptic and Paraventricular Nuclei of the Echidna and Platypus

Ashwell

Lajevardi²,

Cheng³

et al. 2006

Brain Behav Evol

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The monotremes are an intriguing group of mammals that have major differences in their reproductive physiology and lactation from therian mammals. Monotreme young hatch from leathery skinned eggs and are nourished by milk secreted onto areolae rather than through nipples. Parturition and lactation are in part controlled through the paraventricular and supraoptic nuclei of the hypothalamus. We have used Nissl staining, enzyme histochemistry, immunohistochemistry for tyrosine hydroxylase, calbindin, oxytocin, neurophysin and non-phosphorylated neurofilament protein, and carbocyanine dye tracing techniques to examine the supraoptic and paraventricular nuclei and the course of the hypothalamo-neurohypophysial tract in two monotremes: the short-beaked echidna (Tachyglossus aculeatus) and the platypus (Ornithorhynchus anatinus). In both monotremes, the supraoptic nucleus consisted of loosely packed neurons, mainly in the retrochiasmatic position. In the echidna, the paraventricular nucleus was quite small, but had similar chemoarchitectural features to therians. In the platypus, the paraventricular nucleus was larger and appeared to be part of a stream of magnocellular neurons extending from the paraventricular nucleus to the retrochiasmatic supraoptic nucleus. Immunohistochemistry for non-phosphorylated neurofilament protein and carbocyanine dye tracing suggested that hypothalamo-neurohypophysial tract neurons in the echidna lie mainly in the retrochiasmatic supraoptic and lateral hypothalamic regions, but most neurophysin and oxytocin immunoreactive neurons in the echidna were found in the paraventricular, lateral hypothalamus and supraoptic nuclei and most oxytocinergic neurons in the platypus were distributed in a band from the paraventricular nucleus to the retrochiasmatic supraoptic nucleus. The small size of the supraoptic nucleus in the two monotremes might reflect functional aspects of monotreme lactation.

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Section: Course and Origin Of The Hypothalamoneurohypophysial Tractsupporting

confidence: 61%

“…In the avian brain, NPH-and vasotocin-immunoreactive neurons are also found in a paraventricular position [Peczély and Antoni, 1984;Tennyson et al, 1985].…”

Section: Course and Origin Of The Hypothalamoneurohypophysial Tractmentioning

confidence: 99%

The Hypothalamic Supraoptic and Paraventricular Nuclei of the Echidna and Platypus

Ashwell

Lajevardi²,

Cheng³

et al. 2006

Brain Behav Evol

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“…The presence of ghrelin in these cells therefore resembles the presence of arginine vasotocin and mesotocin in the chicken hypothalamus (Tennyson et al 1985, Robinzon et al 1988, Barth et al 1997. Fibers from these cells have been shown to extend to the avian median eminence (Mikami 1985, Tennyson et al 1985, Robinzon et al 1988 and it is therefore possible that ghrelin stimulates pituitary GH after release from these fibers into the hypophysial portal circulation. Most magnocellular neurons do not, however, terminate in the median eminence but in the neurohypophysis.…”

Section: Discussionmentioning

confidence: 88%

Ghrelin: a hypothalamic GH-releasing factor in domestic fowl (Gallus domesticus)

Ahmed¹,

Harvey²

2002

Journal of Endocrinology

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Ghrelin, a recently discovered peptide in the mammalian hypothalamus and gastrointestinal tract is thought to be the endogenous ligand for the GH secretagogue (GHS) receptor and it stimulates GH release in rats and humans. The possibility that ghrelin is present in birds was therefore assessed, since a GHS receptor is present in the chicken pituitary gland.Although immunoreactive ghrelin is readily detectable in the rat stomach and ileum, ghrelin immunoreactivity could not be detected in the chicken proventriculus, stomach, ileum or colon, whereas somatostatin immunoreactivity, in contrast and as expected, was readily detectable in the chicken gastrointestinal tract. Ghrelin immunoreactivity was, however, present in the chicken hypothalamus, although not in the arcuate (infundibular) nucleus, as in rats. Discrete parvocellular cells and neuronal fibers with ghrelin immunoreactivity were present in the anterior medial hypothalamus. This immunoreactivity was specific and completely abolished following the preabsorption of the antibody with an excess of human ghrelin. Ghrelin immunoreactivity was also present in clusters of large ovoid magnocellular cells in the nucleus magnocellularis preopticus pars medialis, nucleus magnocellularis preopticus supraopticus and in the chiasmaopticus. Immunoreactivity for ghrelin was restricted to the cytoplasm of the perikarya and their axonal sprouts. Immunoreactivity for ghrelin was not seen in any other hypothalamic nuclei.In a preliminary experiment, circulating GH concentrations in conscious immature chicks were promptly increased following bolus i.v. administration of human ghrelin. The increase in GH concentration (approximately three times that in the controls) was comparable with that induced by the same dose (10 µg/kg) of human GHreleasing hormone, although less than that (approximately sixfold) induced by thyrotropin-releasing hormone.These results demonstrate the presence of a ghrelin-like protein in the chicken hypothalamus and suggest that it participates in the regulation of GH secretion in birds.

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“…In mammals, the equivalent nonapeptides are measurable within the CSF (7). Alternatively, the nonapep- tides discussed here may be directly involved in differentiation of their own or other cell populations or may support the onset and/or maintainance of cell migration (5). The synthesis of AVT/MT seems to start shortly after the last mitotic division (7).…”

Section: Fig 8g-imentioning

confidence: 92%

Embryonal Development of Arginine Vasotocin/Mesotocin Gene Expression in the Chicken Brain

Milewski

Lvell²,

Großmann

et al. 1989

J Neuroendocrinology

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An ontogenic series of chick embryo brains (4,6,9,12,14,16 and 18 days of incubation, hatching day: 21) was coronally or saggitally sectioned and investigated for expression of the arginine vasotocin (AVT)/mesotocin (MT) gene. To this end a 39mer oligonucleotide recognizing the AVTlMT encoding sequence of their respective mRNAs was constructed employing optimized codon usage and was used for in situ hybridization. AVTlMT mRNA-expressing neurons were first detected on embryonal day (E) 6 adjacent to the third ventricle. By E9 the periventricular nucleus had expanded in size but the hybridization signal was weaker. These results suggest a migration of cells in all directions away from the third ventricle into the diencephalon; some perikarya were even observed at the lateral pial surface above the optic chiasm. By E12, brain differentiation had advanced to distinct hypothalamo-neurohypophyseal nuclei (supraoptic and paraventricular nuclei) as well as to accessory groups expressing AVTlMT mRNA. Two cell types were then distinguishable in the paraventricular nucleus; the specific mRNA was expressed either as a weak or a strong hybridization signal.Comparison with other studies suggested that differentiation had almost attained adult level though cell growth and differentiation of supraoptic and paraventricular nuclei still occurred. This was complete by El8 when individual cells were larger and the intensity of the hybridization signal became very strong.RNase pretreatment depressed the signal by 100%. Northern blot hybridization of RNA extracted from newly hatched chicks verified the specificity of the probe. A single band was evident, indicating an mRNA of approximately 700 bases, which is only found in hypothalamus and not in muscle, liver or extra-hypothalamic brain, and corresponds in size closely with mammalian vasopressin mRNA.The data demonstrate a very early development (E6) of neurohypophyseal hormone gene expression in the chick embryo brain with important differentiation around E9. At El2 magnocellular neuronal arrangement resembled adult neurons but the gene expression signal increased in intensity until E18.Once the egg is shelled inside the hen and once it is layed, the chick embryo develops independently of maternal support. Thus, the chick embryo offers a number of excellent advantages over mammalian systems to study hypothalamo-neurohypophyseal development and function (1). In addition, embryonic tissue is easily accessible and the embryology is well defined. The similarity in the structures, and in part, in the function of neurohypophyseal hormones between mammals and the chicken, suggests that the chicken model could provide very useful information to assess the ontogenetic regulation of these genes and may pertain for all homeotherms.Arginine vasotocin (AVT) and mesotocin (MT) are the avian analogues to the mammalian neuropeptide hormones vasopressin and oxytocin, respectively. Throughout the vertebrates, these neurohypophyseal nonapeptides can be classified into two types according to t...

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Immunocytochemical studies of vasotocin and mesotocin in the hypothalamo-hypophysial system of the chicken

Cited by 45 publications

References 22 publications

The Hypothalamic Supraoptic and Paraventricular Nuclei of the Echidna and Platypus

The Hypothalamic Supraoptic and Paraventricular Nuclei of the Echidna and Platypus

Ghrelin: a hypothalamic GH-releasing factor in domestic fowl (Gallus domesticus)

Embryonal Development of Arginine Vasotocin/Mesotocin Gene Expression in the Chicken Brain

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