Expression of the kisspeptin/gonadotropin-releasing hormone (GnRH) system in the brain of female Chinese sucker (Myxocyprinus asiaticus) at the onset of puberty

Lamprey gonadotropin-releasing hormone was demonstrated in the brains of larval, metamorphic, and adult sea lampreys, Petromyzon marinus, using an immunoperoxidase technique. Gonadotropin-releasing hormone was observed in the neurohypophysis and preoptic area of the brain of larval, metamorphic, juvenile, and prespawning adults. The occurrence of immunoreactive cells and the intensity of the immunostaining was lowest in larvae, but by stage 5 of metamorphosis there was a marked increase in the prevalence and staining of these cells, which continued into adults. In larvae and lampreys in metamorphic stages 1–4, most immunoreactive fibres were confined to the dorsal region of the neurohypophysis. During stage 5 there was an expansion of immunopositive fibres into the ventral portion of the neurohypophysis. Prominent immunoreactivity was observed throughout the neurohypophysis from stage 5 onward through the adult stages. Changes in immunoreactivity of these cells and fibres in the brain and neurohypophysis correlate well with increased concentrations of hormone in the brain during development and with the timing of presumed changes in activity of cells in the adenohypophysis during metamorphosis.

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Live View of Gonadotropin-Releasing Hormone Containing Neuron Migration

Endocrinology ◽

10.1210/en.2004-0838 ◽

2005 ◽

Vol 146 (1) ◽

pp. 463-468 ◽

Cited By ~ 33

Author(s):

Elizabeth P. Bless ◽

Heather J. Walker ◽

Kwok W. Yu ◽

J. Gabriel Knoll ◽

Suzanne M. Moenter ◽

...

Keyword(s):

Real Time ◽

Direct Evidence ◽

Gonadotropin Releasing Hormone ◽

Releasing Hormone ◽

Reproductive Axis ◽

Gnrh Neurons ◽

Migratory Route ◽

The Brain

Neurons that synthesize GnRH control the reproductive axis and migrate over long distances and through different environments during development. Prior studies provided strong clues for the types of molecules encountered and movements expected along the migratory route. However, our studies provide the first real-time views of the behavior of GnRH neurons in the context of an in vitro preparation that maintains conditions comparable to those in vivo. The live views provide direct evidence of the changing behavior of GnRH neurons in their different environments, showing that GnRH neurons move with greater frequency and with more changes in direction after they enter the brain. Perturbations of guiding fibers distal to moving GnRH neurons in the nasal compartment influenced movement without detectable changes in the fibers in the immediate vicinity of moving GnRH neurons. This suggests that the use of fibers by GnRH neurons for guidance may entail selective signaling in addition to mechanical guidance. These studies establish a model to evaluate the influences of specific molecules that are important for their migration.

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On the ‘Visceral Nervous System’ of Ciona

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400015253 ◽

1995 ◽

Vol 75 (1) ◽

pp. 141-151 ◽

Cited By ~ 49

Author(s):

G.O. Mackie

Keyword(s):

Nervous System ◽

Ciona Intestinalis ◽

Gonadotropin Releasing Hormone ◽

Nerve Plexus ◽

Full Extent ◽

Releasing Hormone ◽

Blood Sinus ◽

The Brain

Ciona intestinalis has a well developed nerve plexus associated with the dorsal strand, as first described by Marco Fedele. The dorsal strand plexus is immunoreactive with antisera against gonadotropin-releasing hormone. Immunoreactivity is seen in the cell bodies, which lie peripherally, and in processes which run throughout the dorsal blood sinus, enter the branchial sac and penetrate the brain via the visceral nerve. The plexus provides a rich innervation of the gonoducts, and processes have been seen in the gonads. The pericardium is not innervated by processes from the plexus and the rectum is poorly innervated, but the full extent of the plexus in the viscera remains uncertain. While this study confirms many of Fedele's observations, it does not support the view that the dorsal strand plexus is equivalent to the vertebrate visceral nervous system.

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