Ontogenetic development of gonadotropin-releasing hormone-like immunoreactive neurons in the brain of the chum salmon, Oncorhynchus keta

Chibá, Akira; Oka, Shunya; Honma, Yoshio

doi:10.1016/0304-3940(94)90287-9

Cited by 58 publications

(30 citation statements)

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“…In addition, we failed to find GnRH immunoreactivity in or near the nasal sac, olfactory nerve, or olfactory bulb, the typical locations of GnRH immunoreactivity in species that possess a terminal nerve. Recent evidence indicates that the GnRH-immunoreactive cells in the ventral forebrain of at least some gnathostomes originate in the nasal placode and migrate along the terminal nerve into the forebrain, whereas the immunoreactive cells of the midbrain have a different embryonic origin (Murakami et al, 1992;Chiba et al, 1994;Murakami and Arai, 1994;Northcutt and Muske, 1994;Parhar et al, 1994). Given that lampreys may lack a GnRH-containing midbrain cell group, and lack a terminal nerve (as we will argue below), the development and snatomical organization of the GnRH system of lampreys appears to be somewhat different than that of gnathostomes.…”

Section: Distribution Of Fmrfamide-like and Gnrh Immunoreactivity In mentioning

confidence: 99%

“…The terminal nerve appears to have its embryological origin in the nasal placode (Schwanzel-Fukuda and Pfaff, 1989;Wray et al, 1989;Murakami et al, 1992;Chiba et al, 1994;Murakami and Arai, 1994;Northcutt and Muske, 1994;Parhar et al, 19941, one of the series of neurogenic placodes that originated with the earliest craniates (Northcutt and Gans, 1983); thus, the developmental precursor cells for the terminal nerve may be present in lampreys. Furthermore, placement of horseradish peroxidase or cobaltlysine into the nasal sac labels a group of fibers that passes through the ventromedial olfactory bulb and terminates in several regions, including the hypothalamus and preoptic area in larval Lampetra von Bartheld and Meyer, 1988) and in larval and adult Zchthyomyzon (Northcutt and Puzdrowski, 1988).…”

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confidence: 96%

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Silver lampreys (Ichthyomyzon unicuspis) lack a gonadotropin-releasing hormone- and FMRFamide-immunoreactive terminal nerve

Eisthen

Northcutt

1996

J. Comp. Neurol.

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The terminal nerve is a ganglionated cranial nerve with peripheral processes that enter the nasal cavity and centrally directed processes that enter the forebrain. Members of all classes of gnathostomes have been found to possess a terminal nerve, some components of which demonstrate immunoreactivity to the peptides Phe-Met-Arg-Phe-NH2 (FMRFamide) and gonadotropin-releasing hormone (GnRH). To explore the possibility that lampreys possess a terminal nerve, we examined the distribution of these peptides in the silver lamprey, Ichthyomyzon unicuspis, by using antisera to FMRFamide and to four forms of GnRH. We found cells with FMRFamide-like immunoreactivity in the preoptic area and the isthmal gray region of the mesencephalon, and found labeled fibers throughout the preoptic-infundibular region. Occasional labeled fibers were scattered through many regions of the brain, including the optic nerve and olfactory bulb; however, unlike species that possess a terminal nerve, lampreys have no immunoreactive cells or fibers in the olfactory nerve or nasal epithelia. In addition, we observed GnRH-immunoreactive cell bodies in the preoptic area of all animals and in the ventral hypothalamus of one individual. Most of the labeled fibers extended ventrally to the hypothalamus, with other fibers extending throughout the striatum and hypothalamic-neurohypophyseal region. A few fibers in other regions, including the optic nerve, were also labeled; we detected no immunoreactivity in the olfactory bulb, olfactory nerve, or nasal epithelia. The use of different GnRH antisera resulted in remarkably similar patterns of labeling of both cells and fibers. In summary, we did not observe either GnRH or FMRFamide-like immunoreactivity in the olfactory regions that represent the typical path of terminal nerve fibers, nor were we able to locate a terminal nerve ganglion. We conclude that lampreys may lack a terminal nerve, and that the previously described fiber bundle extending from the nasal sac to the ventral forebrain may constitute an extra-bulbar olfactory pathway.

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Section: Distribution Of Fmrfamide-like and Gnrh Immunoreactivity In mentioning

confidence: 99%

mentioning

confidence: 96%

Silver lampreys (Ichthyomyzon unicuspis) lack a gonadotropin-releasing hormone- and FMRFamide-immunoreactive terminal nerve

Eisthen

Northcutt

1996

J. Comp. Neurol.

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“…A second class of terminal nerve fibers contains a compound that has not been identified, but which displays immunoreactivity to neuropeptide Y (NPY) and to a smaller peptide, Phe-MetArg-Phe-NH 2 (FMRFamide), that resembles the C terminus of the NPY molecule (Chiba et al, 1994(Chiba et al, , 1996Chiba, 2000Chiba, , 2005.…”

Section: Introductionmentioning

confidence: 99%

Terminal Nerve-Derived Neuropeptide Y Modulates Physiological Responses in the Olfactory Epithelium of Hungry Axolotls (Ambystoma mexicanum)

et al. 2006

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The vertebrate brain actively regulates incoming sensory information, effectively filtering input and focusing attention toward environmental stimuli that are most relevant to the animal's behavioral context or physiological state. Such centrifugal modulation has been shown to play an important role in processing in the retina and cochlea, but has received relatively little attention in olfaction. The terminal nerve, a cranial nerve that extends underneath the lamina propria surrounding the olfactory epithelium, displays anatomical and neurochemical characteristics that suggest that it modulates activity in the olfactory epithelium. Using immunocytochemical techniques, we demonstrate that neuropeptide Y (NPY) is abundantly present in the terminal nerve in the axolotl (Ambystoma mexicanum), an aquatic salamander. Because NPY plays an important role in regulating appetite and hunger in many vertebrates, we investigated the possibility that NPY modulates activity in the olfactory epithelium in relation to the animal's hunger level. We therefore characterized the full-length NPY gene from axolotls to enable synthesis of authentic axolotl NPY for use in electrophysiological experiments. We find that axolotl NPY modulates olfactory epithelial responses evoked by L-glutamic acid, a food-related odorant, but only in hungry animals. Similarly, whole-cell patch-clamp recordings demonstrate that bath application of axolotl NPY enhances the magnitude of a tetrodotoxin-sensitive inward current, but only in hungry animals. These results suggest that expression or activity of NPY receptors in the olfactory epithelium may change with hunger level, and that terminal nerve-derived peptides modulate activity in the olfactory epithelium in response to an animal's changing behavioral and physiological circumstances.

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“…Results indicate that GnRH neurons are derived from the olfactory placode (OP) and migrate into the forebrain during prenatal development. In teleost fish, it has been reported by IHC in chum salmon (Chiba et al 1994) and sockeye salmon (Parhar et al 1995) that GnRH (probably sGnRH) neurons originate from the OP and then migrate into the brain along the ON. However, little is known about the differential ontogeny of sGnRH and cGnRH-II systems in the brain of salmonid fish.…”

Section: -1 Ontogenic Development Of Gnrh Neurons In Masu Salmonmentioning

confidence: 99%

Reproductive Biology of Salmoniform and Pleuronectiform Fishes with Special Reference to Gonadotropin-Releasing Hormone (GnRH)

Amano¹

2010

Aqua-BioSci. Monogr. (ABSM)

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Keywords • GnRH AbstractA salmonid fish, masu salmon Oncorhynchus masou, has salmon gonadotropin-releasing hormone (sGnRH) and chicken GnRH-II (cGnRH-II), while a pleuronectiform fish, barfin flounder Verasper moseri, has sGnRH, cGnRH-II and seabream GnRH (sbGnRH). In masu salmon, sGnRH-immunoreactive (ir) cell bodies are scattered from the olfactory nerve through the ventral telencephalon (VT) and the preoptic area (POA). cGnRH-II-ir cell bodies are located in the midbrain tegmentum (MT). sGnRH but not cGnRH-II is detected in the pituitary. sGnRH peptide levels and sGnRH mRNA levels in the VT and the POA increased during gonadal maturation. sGnRH neurons are derived from the olfactory epithelium and migrate into the brain. In barfin flounder, sGnRH-ir, cGnRH-II-ir, and sbGnRH-ir cell bodies are located in the olfactory bulbs and the terminal nerve ganglion (TN), the MT, and the POA, respectively, and these neurons do not migrate in the brain. sbGnRH is detected in the pituitary. sbGnRH mRNA levels in the brain increased during gonadal maturation. Although three GnRH systems exist in the barfin flounder, anatomical distinction between the TN-and the POA-GnRH systems is not clear in masu salmon. Thus, it is suggested that sGnRH neurons in masu salmon play different roles according to the location in the brain. General introductionGonadotropin-releasing hormone (GnRH) is a decapeptide originally isolated from pig and sheep hypothalami as a physiologic regulator of luteinizing hormone (LH) release from the pituitary (Matsuo et al. 1971;Burgus et al. 1972). At present, it is generally accepted that GnRH regulates synthesis and release of pituitary gonadotropin (GTH) (see King and Millar 1992;Sherwood et al. 1993). It has been shown that two or three molecular forms of GnRH exist, even within the same species (Oka 1997;Okuzawa and Kobayashi 1999;Okubo and Nagahama 2008). In addition, GnRH can act as a neuromodulator and has also been implicated in reproductive behavior in many species including teleost fish such as dwarf gourami Colisa lalia (Yamamoto et al. 1997) and goldfish Carassius auratus (Volkoff and Peter 1999).To date, 15 forms of GnRHs have been identified based on their primary structure or complementary DNAs (cDNAs) in vertebrates, as shown in Fig. 1 (Okubo and Nagahama 2008;Kavanaugh et al. 2008). GnRH forms are traditionally named after the species from which they were first identified. In addition to vertebrate species, GnRH was isolated in invertebrates: e.g., in the protochordate Ciona intestinalis (Powell et al. 1996;Adams et al. 2003), octopus Octopus vulgaris (Iwakoshi et al. 2002) and the sea hare Aplysia californica (Zhang et al. 2008).In mammalian, avian, reptilian, and amphibian animals, GnRH is conveyed to the pituitary via the hypothalamo-hypophyseal portal vessels ( Fig. 2A). In mammals, pulsatile release of mammalian GnRH (mGnRH) by hypothalamic neurons stimulates GTH secretion from the pituitary. However, teleost fishes lack the median eminence. Instead, GnRH neurons are found to directly...

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Ontogenetic development of gonadotropin-releasing hormone-like immunoreactive neurons in the brain of the chum salmon, Oncorhynchus keta

Cited by 58 publications

References 15 publications

Silver lampreys (Ichthyomyzon unicuspis) lack a gonadotropin-releasing hormone- and FMRFamide-immunoreactive terminal nerve

Silver lampreys (Ichthyomyzon unicuspis) lack a gonadotropin-releasing hormone- and FMRFamide-immunoreactive terminal nerve

Terminal Nerve-Derived Neuropeptide Y Modulates Physiological Responses in the Olfactory Epithelium of Hungry Axolotls (Ambystoma mexicanum)

Reproductive Biology of Salmoniform and Pleuronectiform Fishes with Special Reference to Gonadotropin-Releasing Hormone (GnRH)

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