scholarly journals Selected body temperature of nine species of Mexican horned lizards (Phrynosoma)

2015 ◽  
Vol 86 (1) ◽  
pp. 275-278 ◽  
Author(s):  
Rafael A. Lara-Reséndiz ◽  
Diego M. Arenas-Moreno ◽  
Elizabeth Beltrán-Sánchez ◽  
Weendii Gramajo ◽  
Javier Verdugo-Molina ◽  
...  
Keyword(s):  
Body Temperature ◽  
Horned Lizards ◽  
Selected Body Temperature

Head-Body Temperature Differences in Horned Lizards

1964 ◽  
Vol 37 (3) ◽  
pp. 273-279 ◽  
Author(s):  
James Edward Heath
Keyword(s):  
Body Temperature ◽  
Horned Lizards

Selected body temperature and thermal tolerance of tadpoles of two frog species (Fejervarya limnocharis and Microhyla ornata) acclimated under different thermal conditions

2012 ◽  
Vol 32 (2) ◽  
pp. 465-471
Author(s):  
张克勤 ZHANG Keqin ◽  
邓秋香 DENG Qiuxiang ◽  
Justin Liu Justin Liu ◽  
蒋诗梦 JIANG Shimeng ◽  
张左娇 ZHANG Zuojiao ◽  
...  
Keyword(s):  
Body Temperature ◽  
Thermal Tolerance ◽  
Thermal Conditions ◽  
Frog Species ◽  
Selected Body Temperature ◽  
Fejervarya Limnocharis

Role of central chemoreceptors in behavioral thermoregulation of the toad, Bufo marinus

1994 ◽  
Vol 266 (5) ◽  
pp. R1483-R1487 ◽  
Author(s):  
L. G. Branco ◽  
S. C. Wood
Keyword(s):  
Body Temperature ◽  
Oxygen Saturation ◽  
Fourth Ventricle ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
Behavioral Thermoregulation ◽  
Peripheral Stimulus ◽  
Central Chemoreceptors ◽  
Selected Body Temperature

We tested the hypothesis that hypercapnia will induce behavioral hypothermia in toads and that central chemoreceptors are involved in this response. Animals were tested in an enclosed temperature gradient supplied with different gas mixtures. Fractional inspired CO2 (FICO2) between 0 and 0.05 had no significant effect on selected body temperature, but FICO2 between 0.06 and 0.10 reduced the selected body temperature from U approximately 28 to 18 degrees C. To determine if the hypercapnia-induced hypothermia is mediated by acidification of central chemoreceptors, the pH of the fourth ventricle was kept constant by perfusion with mock cerebrospinal fluid of pH 7.7 or 7.1 (normal and acidic values, respectively). Ventricular perfusion at pH 7.7 under normocapnic conditions had no effect on body temperature. Hypercapnia (FICO2 0.08) failed to induce hypothermia when the fourth ventricle was kept at pH 7.7 and when hyperoxia was present. Acidic ventricular perfusion under normocapnic conditions decreased selected body temperature from 27 to 25 degrees C, a significant drop but much less than that due to hypercapnia producing the same brain pH, suggesting an important role of peripheral chemoreceptors. The physiological significance of behavioral hypothermia and nature of the peripheral stimulus were evaluated by measuring the effect of hypercapnia on arterial oxygen saturation, PO2, and pH at 15 and 25 degrees C. Arterial oxygen saturation was higher at the lower temperature. Increasing FICO2 decreased oxygen saturation at 25 degrees C but not at 15 degrees C. Arterial PO2 increased with increasing inspired CO2. This increase was greater at 15 degrees C than at 25 degrees C. Arterial pH decreased at both temperatures.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Interaction between temperature and hypoxia in the alligator

1993 ◽  
Vol 265 (6) ◽  
pp. R1339-R1343 ◽  
Author(s):  
L. G. Branco ◽  
H. O. Portner ◽  
S. C. Wood
Keyword(s):  
Body Temperature ◽  
Blood Gases ◽  
The Body ◽  
Plasma Lactate ◽  
Acid Base ◽  
Terrestrial Vertebrates ◽  
Beneficial Response ◽  
Acid Base Status ◽  
Induced Changes ◽  
Selected Body Temperature

Hypoxia elicits behavioral hypothermia in alligators. Under normoxic conditions, the selected body temperature is 27.8 +/- 1.2 degrees C. However, when inspired O2 is lowered to 4%, selected body temperature decreases to 15.4 +/- 1.0 degrees C. The threshold for the behavioral hypothermia is between 4 and 5% inspired O2, the lowest threshold measured so far in terrestrial vertebrates. This study assessed the physiological significance of the behavioral hypothermia. The body temperature was clamped at 15, 25, and 35 degrees C for measurements of ventilation, blood gases, metabolic rate, plasma lactate, and acid-base status. Hypoxia-induced changes in ventilation, acid-base status, oxygen consumption, and lactate were proportional to body temperature, being pronounced at 35 degrees C, less at 25 degrees C, and absent at 15 degrees C. The correlation between selected body temperature under severe hypoxia and the measured parameters show that behavioral hypothermia is a beneficial response to hypoxia in alligators.

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