Histologische, histochemische en experimentele gegevens in verband met de fysiologie van de nevenkieuw der Salmonidae
Derynck, R. (1974). Histologische, histochemische en experimentele gegevens in verband met de fysiologie van de nevenkieuw der Salmonidae. MSc Thesis. Katholieke Universiteit Leuven. Faculteit Wetenschappen: Leuven. 141 pp.
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Document type: Dissertation
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| Keywords |
Salmonidae Jarocki or Schinz, 1822 [WoRMS]
Marine/Coastal |
| Abstract |
In the first chapter of the literature study we described the pseudobranchial morphology of the Teleosts. The pseudobranch that is derived from the spiracular gill of the Elasmobranchs has a filamentary structure and is characterized by the typical "pseudobranchial cells" of which the acidophil granules are situated near the lamellar capillaries. Many arguments point out that the pseudobranchial cells offer from the acidophil cells in the gill, i.e. the chloride cells (VAN DIJCK, 1966 and 1967, HARB and COPELAND, 1969, BONNET, BASTIDE and LAURENT, 1973). Several hypotheses have been worked out as to the physiology of the pseudobranch. COPELAND (1947) proposed an osmoregulatory role. LAURENT et al. on the other hand accept a baro- and chemoreceptor function. Experimental results indicate a possible endocrine function, connected with the eye (PFLUGFELDER, 1952, PARRY and HOLLIDAY, 1960). Serotonin or a related substance can be important here (QUAY, SMART and HAFEEZ, 1969, LANGE, 1973). A histological description of the pseudobranch of Hucho hucho and Salmo salar is given in our personal study. We also compared the pseudobranchial volumes of Salmo trutta from water of pH 6.9 and 8.0 and it is shown that the pseudobranchial development doesn’t depend on the salt concentrations and the pH of the water. This result, like the experimental data of PARRY and HOLLIDAY (1960) contradict the Osmoregulatory function proposed by COPELAND (1947). From the results of the fluorescence microscopic study according to the method of FALCK and OWMAN (1965) and a bioassay on the heart of Anodonta cygnea, we concluded to the presence of serotonin (5-hydroxytryptamine) in the acidophil granules of the pseudobranchial cells of Salmo trutta. But few defined hypotheses about the physiological role of this substance can be postulated. Serotonin might influence the pigmentation via the eye, for it is a direct precursor of melatonin. Besides 5-hydroxytryptamine (VELSH, 1964) and acetylserotonin methyltransferase (QUAY, SMART and HAFEEZ, 1969) have been found in the retina. The released melatonin causes a contraction of the melanophores and so is an antagonist of the hypophyseal MSH (melanophore stimulating hormone). |
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