scholarly journals Effects of temperature on acid–base regulation, gill ventilation and air breathing in the clown knifefish, Chitala ornata

2020 ◽  
Vol 223 (4) ◽  
pp. jeb216481 ◽  
Author(s):  
Le Thi Hong Gam ◽  
Do Thi Thanh Huong ◽  
Dang Diem Tuong ◽  
Nguyen Thanh Phuong ◽  
Frank Bo Jensen ◽  
...  
Keyword(s):  
Acid Base ◽  
Air Breathing ◽  
Gill Ventilation ◽  
Effects Of Temperature

The Effects of Branchial Denervation and Pseudobranch Ablation on Cardioventilatory Control in an Air-Breathing Fish

1991 ◽  
Vol 161 (1) ◽  
pp. 347-365 ◽  
Author(s):  
DAVID J. McKENZIE ◽  
MARK L. BURLESON ◽  
DAVID J. RANDALL
Keyword(s):  
Cardiovascular Responses ◽  
Sodium Cyanide ◽  
Air Breathing ◽  
Ventilatory Responses ◽  
Reflex Bradycardia ◽  
Afferent Information ◽  
Gill Ventilation ◽  
Air Ventilation ◽  
Amia Calva

Present address and address for reprint requests: Istituto di Scienze Farmacologiche, via Balzaretti 9, Università di Milano, Milano 20133, Italy. The role of sensory afferent information from the gills of Amia calva in cardiovascular and ventilatory control was investigated by bilateral branchial denervation and pseudobranch ablation. Aquatic hypoxia or 1 mg of sodium cyanide (NaCN) in the water flowing over the gills stimulated bradycardia, and gill and air ventilation in sham-operated fish. Sodium cyanide, noradrenaline (NA) and adrenaline (A) infusion into the dorsal aorta increased gill ventilation, and NA and A infusion also stimulated tachycardia and an increase in blood pressure. Following denervation and pseudobranch ablation, O2 consumption (V·OO2), airbreathing frequency (fAB) and arterial O2 tension (PaOO2) declined, and circulating NA levels increased, as compared with sham-operated fish. Cardiovascular and air-breathing responses to hypoxia were abolished and gill ventilatory responses attenuated. All ventilatory and cardiovascular responses to NaCN were abolished and gill ventilatory responses to NA and A were attenuated in animals following denervation and pseudobranch ablation. These results demonstrate that O2-sensitive chemoreceptors in the gills and pseudobranch control reflex bradycardia and air-breathing responses in Amia, but that gill ventilatory responses to hypoxia, NA and A are partially mediated by extrabranchial mechanisms. Plasma NA levels increased during hypoxia in shamoperated and denervated animals, indicating that circulating NA may have mediated gill ventilatory responses in denervated animals.

Equilibrium Studies of Alkyltin(IV) Complexes with D-Glucosamine

1997 ◽  
Vol 62 (7) ◽  
pp. 1023-1028 ◽  
Author(s):  
Mohamed M. Shoukry ◽  
Samir M. El-Medani
Keyword(s):  
Complex Formation ◽  
Stability Constants ◽  
Acid Base ◽  
Complex Formation Equilibria ◽  
Equilibrium Studies ◽  
Formation Equilibria ◽  
Effects Of Temperature ◽  
The Stability

The acid-base and complex-formation equilibria involving glucosamine and its complexes with alkyltin(IV) chlorides have been studied by potentiometric technique. The results prove to a formation of 1 : 1 complex with trialkyltin(IV) and both 1 : 1 and 1 : 2 complexes with dialkyltin(IV) species. The stability constants in water were determined, the effects of temperature (from 15 to 35 °C) and ethanol (up to 88 vol.%) was studied and the speciation of the complexes was resolved.

scholarly journals Acid–base regulation in the air-breathing swamp eel (Monopterus albus) at different temperatures

2018 ◽  
Vol 221 (10) ◽  
pp. jeb172551 ◽  
Author(s):  
Phan Vinh Thinh ◽  
Nguyen Thanh Phuong ◽  
Colin J. Brauner ◽  
Do Thi Thanh Huong ◽  
Andrew T. Wood ◽  
...  
Keyword(s):  
Acid Base ◽  
Air Breathing ◽  
Monopterus Albus ◽  
Different Temperatures ◽  
Swamp Eel

scholarly journals High capacity for extracellular acid-base regulation in the air-breathing fish Pangasianodon hypophthalmus

2015 ◽  
Vol 218 (9) ◽  
pp. 1290-1294 ◽  
Author(s):  
C. Damsgaard ◽  
L. T. H. Gam ◽  
D. D. Tuong ◽  
P. V. Thinh ◽  
D. T. Huong Thanh ◽  
...  
Keyword(s):  
High Capacity ◽  
Acid Base ◽  
Air Breathing ◽  
Pangasianodon Hypophthalmus

scholarly journals Control of gill ventilation and air-breathing in the bowfin amia calva

1999 ◽  
Vol 202 (1) ◽  
pp. 87-94
Author(s):  
M.S. Hedrick ◽  
D.R. Jones
Keyword(s):  
Bladder Volume ◽  
Control Fish ◽  
Type I ◽  
Type Ii ◽  
Afferent Pathways ◽  
Air Breathing ◽  
Gas Bladder ◽  
Stretch Receptors ◽  
Gill Ventilation ◽  
Amia Calva

The purpose of this study was to investigate the roles of branchial and gas bladder reflex pathways in the control of gill ventilation and air-breathing in the bowfin Amia calva. We have previously determined that bowfin use two distinct air-breathing mechanisms to ventilate the gas bladder: type I air breaths are characterized by exhalation followed by inhalation, are stimulated by aquatic or aerial hypoxia and appear to regulate O2 gas exchange; type II air breaths are characterized by inhalation alone and possibly regulate gas bladder volume and buoyancy. In the present study, we test the hypotheses (1) that gill ventilation and type I air breaths are controlled by O2-sensitive chemoreceptors located in the branchial region, and (2) that type II air breaths are controlled by gas bladder mechanosensitive stretch receptors. Hypothesis 1 was tested by examining the effects of partial or complete branchial denervation of cranial nerves IX and X to the gill arches on gill ventilation frequency (fg) and the proportion of type I air breaths during normoxia and hypoxia; hypothesis II was tested by gas bladder inflation and deflation. Following complete bilateral branchial denervation, fg did not differ from that of sham-operated control fish; in addition, fg was not significantly affected by aquatic hypoxia in sham-operated or denervated fish. In sham-operated fish, aquatic hypoxia significantly increased overall air-breathing frequency (fab) and the percentage of type I breaths. In fish with complete IX-X branchial denervation, fab was also significantly increased during aquatic hypoxia, but there were equal percentages of type I and type II air breaths. Branchial denervation did not affect the frequency of type I air breaths during aquatic hypoxia. Gas bladder deflation via an indwelling catheter resulted in type II breaths almost exclusively; furthermore, fab was significantly correlated with the volume removed from the gas bladder, suggesting a volume-regulating function for type II air breaths. These results indicate that chronic (3–4 weeks) branchial denervation does not significantly affect fg or type I air-breathing responses to aquatic hypoxia. Because type I air-breathing responses to aquatic hypoxia persist after IX-X cranial nerve denervation, O2-sensitive chemoreceptors that regulate air-breathing may be carried in other afferent pathways, such as the pseudobranch. Gas bladder deflation reflexly stimulates type II breaths, suggesting that gas bladder volume-sensitive stretch receptors control this particular air-breathing mechanism. It is likely that type II air breaths function to regulate buoyancy when gas bladder volume declines during the inter-breath interval.

Effects of temperature and acid-base state on hippocampal population spikes in hamsters

1990 ◽  
Vol 258 (5) ◽  
pp. R1140-R1146 ◽  
Author(s):  
P. Eckerman ◽  
K. Scharruhn ◽  
J. M. Horowitz
Keyword(s):  
Hippocampal Slices ◽  
Pyramidal Cells ◽  
Effect Of Temperature ◽  
Acid Base ◽  
Bathing Medium ◽  
Maximal Stimulation ◽  
Synchronous Firing ◽  
Acid Base Status ◽  
Effects Of Temperature ◽  
Induced Changes

Previous studies have shown that changes in temperature, within the range encountered by hamsters entering hibernation, alter the evoked response of hippocampal pyramidal cells to stimulation of an afferent pathway. The present study was designed to determine whether these alterations are due to changes in the acid-base status of the neural tissue brought about by changes in temperature. Extracellular-evoked responses were recorded from hamster hippocampal slices after Schaffer collateral stimulation. The pH was changed by varying the concentration of CO2 aerating the bathing medium. Buffers contained either 26 or 40 mM bicarbonate ion. The width of the population spike (the synchronous firing of pyramidal cells) was measured as pH was varied between 7.5 and 7.1, with slice temperature set at either 25 or 20 degrees C. There was a significant increase in spike width as temperature was lowered to 20 degrees C, but no significant change in spike width or amplitude as pH or bicarbonate was varied. The effect of temperature (20 degrees C for half-maximal stimulation, and from 20 to 25 degrees C for just maximal stimulation) on spike width and amplitude thus does not appear to be due to pH- or bicarbonate-induced changes.

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