The Pituitary Gland of the Oviparous Caecilian, Ichthyophis beddomei

Masood-Parveez, U.; Bhatta, Gopalakrishna; Nadkarni, V. B.

doi:10.2307/1564626

Cited by 6 publications

(4 citation statements)

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“…1, 2m,n, 5b,c). Some of these fibers, however, do not terminate around the blood capillaries of the median eminence but course farther caudally through the infundibular stalk (see Masood-Parveez et al, 1994) toward the pars nervosa, which is located at the dorsocaudal tip of the pars distalis of the pituitary (Figs. 1, 2o,p).…”

Section: Distribution Of Gnrh-immunoreactive Fibersmentioning

confidence: 99%

Distribution of gonadotropin-releasing hormone immunoreactivity in the brain ofIchthyophis beddomei (amphibia: gymnophiona)

et al. 1997

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From a comparative viewpoint, we have investigated the presence and neuroanatomical distribution of gonadotropin-releasing hormone (GnRH)-immunoreactive material in the brain of a gymnophione amphibian, Ichthyophis beddomei. Immunocytochemical analysis of the adult brain and terminal nerves in both sexes shows the presence of neurons and fibers containing mammalian GnRH (mGnRH)- and chicken GnRH-II (cGnRH-II)-like peptides. With respect to GnRH-immunoreactive material, there are two distinct neuronal systems in the brain: one containing mGnRH, which is located in the forebrain and terminal nerve, and the other containing cGnRH-II, which is restricted to the midbrain tegmentum. Basically, this distribution pattern parallels that of many species of anurans and a urodele. Whereas the presence of cGnRH-II-immunoreactive fibers in the dorsal pallium of L. beddomei is a feature in common with a urodele amphibian, the total absence of cGnRH-II-like material in the median eminence is unique to this species. It is suggested here that the distribution profile of GnRH-like material within the brain and terminal nerve of I. beddomei represents a primitive pattern.

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Section: Distribution Of Gnrh-immunoreactive Fibersmentioning

confidence: 99%

Distribution of gonadotropin-releasing hormone immunoreactivity in the brain ofIchthyophis beddomei (amphibia: gymnophiona)

et al. 1997

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“…Moodie, 1978;Wake, 1980b;Wilkinson, 1992), physiology (e.g. Stiffler et al, 1990;Masood-Parveez et al, 1994;Stiffler & Manokham, 1994), sensory biology (e.g. Himstedt 8r.…”

Section: Introductionmentioning

confidence: 99%

A comparative study of locomotion in the caecilians Dermophis mexicanus and Typhlonectes natans (Amphibia: Gymnophiona)

Summers

O’Reilly

1997

Zoological Journal of the Linnean Society

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We compared locomotion of two species of caecilian using x-ray videography of the animals traversing smooth-sided channels and a pegboard. Two channel widths were used, a body width channel and a body width + 20°/o channel. The terrestrial caecilian, Demophis mexicanus, used internal concertina locomotion in both channels and lateral undulation on the pegboard. The aquatic caecilian, lyhlonectes natans, was not able to move at all in the body width channel. In the wider channel 7yhlonectes proceeded at the same speed as Demophis while using normal, rather than internal, concertina locomotion. O n the pegboard, 9phlonectes used lateral undulation and achieved 2.5 times the speed managed by Dmophis. A phylogenetic analysis of this, and other, evidence shows that (1) internal Concertina evolved in the ancestor to extant caecilians and (2) internal concertina locomotion was secondarily lost in the aquatic caecilians. 0 1997 The Linnran Socktv of Loridon

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“…Dense fibers from these cells likely project to the posterior pituitary and correspond to neurosecretory cells in the paraventricular and supraoptic nuclei of reptiles, birds, and mammals (see, e.g., Swaab and Pool, 1975;Stoll and Voorn, 1985;Kiss et al, 1987;Smeets et al, 1990;Propper et al, 1992). The histological structure of caecilian pituitary is similar to that of other amphibians (Schubert et al, 1977;Doerr-Schott and ZuberVogeli, 1984;Masood-Parveez et al, 1994), and we isolated very large concentrations of AVT from the pituitary of T. natans. In contrast to other vertebrates, however, there was no bimodal distribution of AVT-ir cell sizes in the caecilian POA and no indication of a separate ''magnocellular'' nucleus.…”

Section: Discussionmentioning

confidence: 63%

Identification and localization of neurohypophysial peptides in the brain of a caecilian amphibian,Typhlonectes natans (amphibia: Gymnophiona)

1998

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The amphibian order Gymnophiona contains more than 150 different species of caecilians. The characterization and distribution of neurohypophysial peptides, however, has not been described for any member of this order. By using high-performance liquid chromatography, radioimmunoassay, and mass spectrometry, we identified the peptide arginine vasotocin (AVT) in brain and pituitary extracts from the caecilian Typhlonectes natans. By using immunocytochemistry, we found five populations of AVT-immunoreactive (AVT-ir) cells in the brain of T. natans. AVT-ir cell bodies were located in the preoptic area, amygdala pars medialis, ventral thalamus, dorsal hypothalamic nucleus, and nucleus of the solitary tract. AVT-ir fibers and terminal fields were widespread. We also identified a mesotocin-like peptide. The distribution of this peptide in the brain of T. natans was more restricted than the distribution of AVT. Mesotocin-like-immunoreactive cell bodies were located almost exclusively in the preoptic area, with only a few other cells located in the amygdala pars medialis. This caecilian species, therefore, possesses neurohypophysial peptides that are similar in their structure and distribution to the peptides found in anuran and urodele amphibian orders.

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The Pituitary Gland of the Oviparous Caecilian, Ichthyophis beddomei

Cited by 6 publications

References 0 publications

Distribution of gonadotropin-releasing hormone immunoreactivity in the brain ofIchthyophis beddomei (amphibia: gymnophiona)

Distribution of gonadotropin-releasing hormone immunoreactivity in the brain ofIchthyophis beddomei (amphibia: gymnophiona)

A comparative study of locomotion in the caecilians Dermophis mexicanus and Typhlonectes natans (Amphibia: Gymnophiona)

Identification and localization of neurohypophysial peptides in the brain of a caecilian amphibian,Typhlonectes natans (amphibia: Gymnophiona)

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