Christian Aimar

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The activity of prolactin (PRL) cells was investigated in goldfish gradually adapted to diluted (30%) artificial seawater (ASW) or directly immersed in 23% ASW and in similar saline solutions free of calcium. When Ca2+ is omitted, PRL cells appear slightly more active than those in saline solutions with calcium, nuclear areas having intermediate values(More)
Pleurodeles waltl (amphibian, Urodele) is an appropriate biological model for space experiments on a vertebrate. One reason for interest in this animal concerns the study of the effects of absence of gravity on embryonic development. First, after mating (on Earth) the females retain live, functional sperm in their cloacum for up to 5 months, allowing normal(More)
In vertebrates, only few experiments have been performed in microgravity to study the embryonic development from fertilization. To date, these concern only amphibian and fish. We report here a study on the embryonic development of Pleurodeles waltl (urodele amphibian) eggs oviposited in microgravity. The experiment was performed twice on board the Mir space(More)
Effects of microgravity (microG) on fertilization were studied in the urodele amphibian Pleurodeles waltl on board the MIR space station. Genetic and cytomorphologic analyses ruled out parthenogenesis or gynogenesis and proved that fertilization did occur in microG. Actual fertilization was demonstrated by the analysis of the distribution of peptidase-1(More)
Injection of 5-hydroxytryptophan (5-HTP), a precursor of serotonin, induces dispersion of melanin in the amphibians, Pleurodeles waltlii (Urodela) and Xenopus laevis (Anura), in the goldfish, Carassius auratus, and in the carp, Cyprinus carpio. It is accompanied by a dispersion of erythrophore pigments. In the pituitaries of Pleurodeles and goldfish, a(More)
The cytological responses of the pituitary gland during adaptation to deionized water (DW) were investigated in the goldfish and the eel. In both teleost species, a stimulation of the prolactin (PRL) cells could not be detected, although the levels of blood electrolytes (Na+, Ca2+, Cl-) are reduced in the eel. PRL cells appear less active in DW-adapted(More)
A mutation which affects the eggs was detected in a Pleurodeles waltl laboratory strain. About 4 to 5 hours after fertilization, i.e. before the first cleavage, mutant eggs exhibited one or more depigmented patches (DP) on the animal hemisphere. Later on, some eggs failed to cleave, or cleaved abnormally. However, if gastrulation was successful, further(More)
In the goldfish, one cell type of the pars intermedia, slightly PAS positive, is highly stimulated in deionized water (E Dés). This response is not influenced by the pH of the water (E Dés pH 5.3, E Dés buffered with imidazole pH 6.7) for 20 days. Stimulation is prevented when the E Dés is supplemented with CaCl2 (2mM), but it is not affected by the(More)