Gonadotropin-releasing hormone analog buserelin causes neuronal loss in rat gastrointestinal tract

Gonadotropin-releasing hormone (GnRH) analogs are given to women undergoing in vitro fertilization. Case reports describing the development of chronic intestinal pseudo-obstruction and auto-antibodies against GnRH after such treatment suggest a strong association between intestinal dysfunction and GnRH analogs. No experimental model for studying such a relationship is currently at hand. Our main goal was to investigate possible enteric neurodegeneration and titers of GnRH antibodies in response to repeated administration of the GnRH analog buserelin in rat. Rats were treated for 1–4 sessions with daily subcutaneous injections of buserelin or saline for 5 days, followed by 3 weeks of recovery. Buserelin treatment caused significant loss of submucous and myenteric neurons in the fundus, ileum, and colon. The loss of enteric neurons can, at least partly, be explained by increased apoptosis. No GnRH- or GnRH-receptor-immunoreactive (IR) enteric neurons but numerous luteinizing hormone (LH)-receptor-IR neurons were detected. After buserelin treatment, the relative number of enteric LH-receptor-IR neurons decreased, whereas that of nitric-oxide-synthase-IR neurons increased. No intestinal inflammation or increased levels of circulating interleukins/cytokines were noted in response to buserelin treatment. Serum GnRH antibody titers were undetectable or extremely low in all rats. Thus, repeated administrations of buserelin induce neurodegeneration in rat gastrointestinal tract, possibly by way of LH-receptor hyperactivation. The present findings suggest that enteric neurodegenerative effects of GnRH analog treatment in man can be mimicked in rat. However, in contrast to man, no production of GnRH auto-antibodies has been noted in rat.     

Freshwater mussels (genus Anodonta) from Anatolia and adjacent areas (Bivalvia,Unionidae)

Abstract

A review is given of the species of Anodontinae in Anatolia and the adjacent areas, based mainly on the author’s collections. Five species (A. anatina, A. cygnae, A. palustris, A. pseudodopsis, A. vescoiana) and several subspecies are recognized. Their distribution and the patterns of subspeciation are discussed.     

Marine molluscs from the Iztuzu beach near Dalyan (Mediterranean coast of Turkey)

Abstract

A total of l84 species of marine molluscs has been identified from shells collected on the beach of Iztuzu near Dalyan (Mu?la province, Turkey). Of these, 16 species of gastropod and 4 species of bivalvia are new For the extreme Eastern Mediterranean. Only three species of Lessepsian migrants (from the Red Sea via the Suez canal) have been found.     

Endocrine Organs of a Parasitic Male Deep-Sea Angler-Fish,Edriolychnus schmidti

The parasitic male deep-sea angler-fish Edriolychnus schmidti Regan 1925, which was described by Regan and Trewavas 1932, was reinvestigated with respect to the endocrine organs. Although the original microscopical sections are not in a good condition, it could be concluded that those organs which are involved in regulation of various internal environmental factors, as well as those involved in adaption to external factors, appear poorly developed or reduced. Mechanisms regulating reproductive activities seem to be well developed; a pronounced tuberis region is seen in the otherwise reduced brain and the peculiar pituitary gland appears to contain secretory active cells.     

Light Microscopical and Ultrastructural Organization of Muscles of Priapulus caudatus (Priapulida) and Their Responses to Drugs, with Phylogenetic Remarks

The muscle fibres of the marine invertebrate Priapulus caudatus (Priapulida) are obliquely striated. Thin and thick filaments and characteristic dyad structures were recognized. The ultrastructural organization shows more resemblances with that of arthropod muscles than with that of annelids or molluscs. Pharmacological studies show that the muscles are provided with "primitive" C 16 type of acetylcholine receptors. Tubocurarine, succinylcholine and decamethonium do not block the effect of acetylcholine but potentiate this. This remarkable response may be due to inhibition of choline esterase. No distinct structural or functional differences were observed between somatic and visceral muscles, but the rectum showed evidence of the presence of unspecific amine receptors. The pharmacological responses resemble in the main those known from various simply organized invertebrate phyla. The priapulids, as suggested by Lang in 1953, may te survivors of a very ancient animal group.     

Carotenoids of Prymnesiophyceae (Haptophyceae)

A quantitative study, including mass spectrometric identification, of the carotenoids isolated from some selected prymnesiophytes harvested in exponential growth phase has been carried out. Isochrysis galbana, Hymenomonas carterae, Prymnesium parvum, Pavlova (Monochrysis) lutheri and a Pavlova sp. all produce β,β-carotene, diatoxanthin, diadinoxanthin and fucoxanthin (major carotenoid) in various proportions, in addition to several minor carotenoids were found characteristic of each alga. 19'-Hexanoyloxyfucoxanthin, previously shown to be the major carotenoid in the prymnesiophyte Emeliana (Coccolithus) huxleyi, was not encountered in the Prymnesiophyceae studied here, and we conclude that this carotenoid should be critically looked for in other members of the Gephyrocapsaceae to which E. huxleyi belongs. We further conclude that the carotenoid complement of the Chrysophyceae (in the narrow sense) should be compared with that of the Prymnesiophyceae.