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The effects of acid and acid/aluminum exposure on circulating plasma cortisol levels and other blood parameters in the rainbow trout, Salmo gairdneri (1988)

Goss, G. G. ; Wood, C. M.

Oxford, UK : Blackwell Publishing Ltd

Journal of fish biology 32 (1988), S. 0

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ISSN: 1095-8649

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: Softwater (Ca2+=50, Na+= 50(μequiv. l−1) acclimated rainbow trout were fitted with chronic arterial catheters to allow for repetitive blood sampling. After 48 h recovery they were then exposed to either control (pH 6.5, Al = 0μg l−1), acid (pH 4.8, Al = 0μg l−1) or acid plus aluminum (pH 4.8, A1 = 112 μg l−1) conditions for 72 h. Parameters measured included blood glucose, lactate, haemoglobin, haematocrit and plasma Na+, Cl−, protein and cortisol.Exposure to pH 4′8 alone caused no mortality, a moderate ionoregulatory disturbance and a transient elevation in plasma cortisol. All other parameters were not significantly different from controls. Addition of aluminum to this exposure caused 100% mortality with a mean survival time of only 27.0 h. There was a marked decrease in plasma ions, hyperglycemia, lactate accumulation, haemoconcentration, red cell swelling, and a sharp rise in plasma cortisol becoming greatly increased as the fish neared death. The mechanism of toxicity of acute acid/aluminum exposure, the role for cortisol under such conditions, and the validity of cortisol and glucose as indicators of stress in fish are discussed.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1095-8649.1988.tb05335.x

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Gill morphology during hypercapnia in brown bullhead (Ictalurus nebulosus): role of chloride cells and pavement cells in acid-base regulation (1994)

Goss, G. G. ; Laurent, P. ; Perry, S. F.

Oxford, UK : Blackwell Publishing Ltd

Journal of fish biology 45 (1994), S. 0

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ISSN: 1095-8649

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: The role of gill chloride cells (CCs) and pavement cells (PVCs) in acid-base regulation was evaluated in brown bullhead catfish (Ictalurus nebulosus) subjected to acute hypercapnia (water Pco2=15 torr). Chronic (10 day) cortisol treatment was used as a tool to cause CC proliferation to permit a comparison of the regulatory capacities in groups of fish with widely different gill CC populations. Cortisol (4mg kg−1 day−1) caused a pronounced increase (170%) in the surface area of CCs exposed to the water based on scanning and transmission electron microscope analysis. The density of PVC apical membrane microvilli was significantly increased (20%) by cortisol treatment. Exposure of either group of fish to hypercapnia caused similar changes in gill epithelial morphology including: (i) a marked reduction in the surface area of exposed CCs (52 and 78% reduction in the control and cortisol-treated fish, respectively); and (ii) pronounced increases in PVC apical membrane microvilli density (21 and 27% in the control and cortisol-treated fish, respectively).The rates of Cl− uptake (Jincl−) and Na+ uptake (JinNa+) were elevated (150 and 262%, respectively) in the cortisol-treated fish. Regardless of treatment, Jincl− was markedly reduced to approximately the same levels after 6 h of hypercapnia, JinNa+ was stimulated in the control group and reduced in the cortisol-treated group and thus, after 6 h of hypercapnia, JinNa+ was equal in each group. The similar morphological responses in fish possessing different initial populations suggests that the predominant mechanism of acid-base regulation during hypercapnia, reduction of C1−/HCO3− exchange, is accomplished by removal of the CC-associated C1-/HCO3− exchange sites from the water. The increase in PVC microvilli density during hypercapnia suggests a role for the PVC in acid-base regulation.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1095-8649.1994.tb00938.x

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Interrelationships between gill chloride cell morphology and calcium uptake in freshwater teleosts (1992)

Perry, S. F. ; Goss, G. G. ; Fenwick, J. C.

Springer

Fish physiology and biochemistry 10 (1992), S. 327-337

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ISSN: 1573-5168

Keywords: Oncorhynchus mykiss ; Ictalurus nebulosus ; Anguilla rostrata ; gill ; chloride cell ; cortisol ; calcium uptake ; morphology

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract The involvement of the freshwater fish gill chloride cells (CCs) in trans-branchial calcium uptake (JinCa2+) was investigated. This was accomplished by assessing the interspecific relationships between the apical surface area of CCs exposed to the external environment and JinCa2+. Three species of freshwater teleosts, the rainbow trout (Oncorhynchus mykiss), the American eel (Anguilla rostrata) and the brown bullhead catfish (Ictalurus nebulosus), were used. Chronic (ten-day) treatment with cortisol in each species was used as a tool to evoke variations in both JinCa2+ and gill CC morphology in order to assess intraspecific relationships between CC surface area and JinCa2+. The results of quantitative morphometry, based on analysis of scanning electron micrographs, demonstrated that catfish possessed the lowest fractional area of exposed CC (CCFA) on the gill filament epithelium (12,744 ± 2248 μm2/mm2) and was followed, in increasing order, by American eel (21,355 ± 981 μm2/mm2) and rainbow trout (149,928 ± 26,545 μm2/mm2). With the exception of catfish, chronic treatment with cortisol caused significant increases in CCFA owing to proliferation of CCs and/or enlargement of individual CCs (eel only). The rates of JinCa2+ closely reflected the CC fractional area in each species. The results of correlation analysis revealed significant correlations between CC fractional area and JinCa2+ in trout and eel. Owing to the absence of an effect of cortisol treatment, there was no significant correlation in catfish because of insufficient variation in CC fractional area in this species. CC fractional area was significantly correlated with JinCa2+ among the three species examined. These results suggest that CC is involved in calcium uptake in freshwater teleosts and that both intra- and interspecific differences in the rates of calcium uptake can be accounted for by variability in the surface area of exposed CCs on the gill epithelia.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00004482

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The effects of experimentally altered gill chloride cell surface area on acid-base regulation in rainbow trout during metabolic alkalosis (1994)

Perry, S. F. ; Goss, G. G.

Springer

Journal of comparative physiology 164 (1994), S. 327-336

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ISSN: 1432-136X

Keywords: Gill chloride cell ; Cl-/HCO3 - exchange ; Cortisol ; Acid-base regulation ; Trout, Oncorhynchus mykiss

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine

Notes: Abstract To evaluate the role of the gill chloride cells in regulating metabolic alkalosis in rainbow trout (Oncorhynchus mykiss), the surface area of branchial chloride cells was altered experimentally using combined cortisol/ovine growth hormone injections. Long-term (10-day) treatment of fish with cortisol/ovine growth hormone caused an increase in the two-dimensional chloride cell fractional surface area when compared to uninjected fish (from 8.4 to 29.7%). This was the combined result of an increase in the size of individual cells (from 34.6 to 59.2 μm2) and increased numbers of cells (from 2368 to 5006 cells · mm-2). Metabolic alkalosis was induced by intra-arterial infusion of 140 mmol · l-1 NaHCO3; control fish were infused with 140 mmol · l-1 NaCl. Blood pH and plasma [HCO3 -] increased in both the untreated and the cortisol/ovine growth hormone-treated fish. However, the increases in pH (from 8.05 to 8.53) and [HCO3 -] (from 5.9 to 22.2 mmol · l-1) in the untreated fish were significantly greater than in the cortisol/ovine growth hormone-treated fish (pH increased from 7.78 to 8.11; [HCO3 -] increased from 5.5 to 13.9 mmol · l-1). In all fish, NaHCO3 infusion elicited an increase in the rate of branchial basic equivalent excretion (acidic equivalent uptake) which, in turn, was caused by decreases and increases in branchial Na+ uptake and Cl- uptake, respectively. In the untreated fish, there was a pronounced increase (75%) in chloride cell surface area during NaHCO3 infusion. The attenuation of the metabolic alkalosis during HCO3 - infusion in the cortical/ovine growth hormone-treated fish was caused, at least in part, by an enhancement of branchial basic equivalent excretion. In these fish that already displayed a proliferation of chloride cells, there was no further increase in chloride cell surface area. The changes in Na+ influx and Cl- influx were quantitatively similar during NaHCO3 infusion in both groups. This suggests that the greater rate of base excretion in the cortisol/ovine growth hormone-treated fish was caused by a greater percentage of Cl- uptake being coupled to HCO3 - excretion and less to Cl- excretion (Cl- exchange diffusion).

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00346451

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