title: [The secretory activity of the large-cell hypothalamic nuclei in the humpback salmon Oncorhynchus gorbuscha Walbaum (Salmonidae) during the transition from sea to river and the reverse].
abstract: Nuclei of the hypothalamus of Oncorhynchus gorbuscha Walbaum (Salmonidae) were studied morphologically after passing from the sea to the river at the period of spawning migration and then after the artificial carrying of the fish adapted to fresh water back to the sea. It was found that in peptidergic nuclei of the thalamus during first hours in fresh water there occurs activation of both the synthesis and evacuation of neurosecretion. In the preoptic nucleus the synthesis is activated in perikaryons of all the cells simultaneously, the cells being involved in elimination of the secretion in turn. In the lateral nucleus the secretion elimination takes place simultaneously in all the cells while signs of increased synthesis made their appearance later. By the end of the first day in fresh water both the synthesis and secretion in both nuclei are decreased. After the artificial carrying of gorbuscha back to the sea the preoptic nucleus is first activated and then, 1 day later, there appear signs of decreased activity. Soon after that they die. The lateral nucleus is not active after the artificial carrying of gorbuscha to the sea. Comparison of the results obtained with literature data shows that the preoptic nucleus of salmon reacts specifically to different extreme conditions and not by the type of universal stress-reaction as most vertebrates.
authors.forename: V V
authors.initials: VV
authors.lastname: Sheĭko
authors.forename: A A
authors.initials: AA
authors.lastname: Maksimovich
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D005260:Female; D005618:Fresh Water; D007026:Hypothalamic Area, Lateral / Q000378:metabolism*; D008297:Male; D009490:Neurosecretory Systems / Q000502:physiology*; D009997:Osmotic Pressure; D011301:Preoptic Area / Q000378:metabolism*; D012474:Salmon / Q000502:physiology*; D012623:Seawater; D013312:Stress, Physiological / Q000503:physiopathology / Q000662:veterinary; D013997:Time Factors
vernacular_title: Sekretornaia aktivnost' krupnokletochnykh iader gipotalamusa gorbushi Oncorhynchus gorbuscha Walbaum (Salmonidae) pri perekhode ee iz moria v reku i obratnom perenose.