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• 1. [Article] Behavioral Temperature Regulation in the Turtle Pseudemys Scripta Elegans

  A group of red-eared turtles (Pseudemys scripta elegans) was acclimated to 18-20˚C and artificial photo-period for 21 days. The animals were then individually placed in a thermal gradient and their selected ...

  Citation × Citation Citation Abstract Copy Title: Behavioral Temperature Regulation in the Turtle Pseudemys Scripta Elegans Author: Johnston, Michael H. Year: 1977 A group of red-eared turtles (Pseudemys scripta elegans) was acclimated to 18-20˚C and artificial photo-period for 21 days. The animals were then individually placed in a thermal gradient and their selected temperatures were continuously recorded for 24 hours. A second group of turtles was acclimatized to 7.5-11.0˚C and natural photoperiods for 28 days, and subsequently tested in the same manner as the first group. Lastly, the turtles in the first group, after being acclimated to 3.0˚C and the previous artificial photoperiod for 14 days, were retested in the gradient. Title: Behavioral Temperature Regulation in the Turtle Pseudemys Scripta Elegans Author: Johnston, Michael H. Year: 1977 A group of red-eared turtles (Pseudemys scripta elegans) was acclimated to 18-20˚C and artificial photo-period for 21 days. The animals were then individually placed in a thermal gradient and their selected temperatures were continuously recorded for 24 hours. A second group of turtles was acclimatized to 7.5-11.0˚C and natural photoperiods for 28 days, and subsequently tested in the same manner as the first group. Lastly, the turtles in the first group, after being acclimated to 3.0˚C and the previous artificial photoperiod for 14 days, were retested in the gradient. Close

• 2. [Article] Thermoregulation in Mice under the Influence of Ethanol

  Thermoregulation after acute ethanol, during chronic exposure and during withdrawal from ethanol dependency was studied using genetically heterogeneous (HS) mice, and lines of mice selected in replicate ...

  Citation × Citation Citation Abstract Copy Title: Thermoregulation in Mice under the Influence of Ethanol Author: O'Connor, Candace Sharon Year: 1993 Thermoregulation after acute ethanol, during chronic exposure and during withdrawal from ethanol dependency was studied using genetically heterogeneous (HS) mice, and lines of mice selected in replicate for smaller (HOT1, HOT2) or greater (COLD1, COLD2) decline in rectal temperature (Tre ) after intraperitoneal ethanol. First, HS mice were injected with 20% ethanol in 0.9% NaCI, or NaCI alone during sessions of behavioral thermoregulation in individual temperature gradients (9-38°C). Internal temperature (Tj ) was monitored with implanted telemetry devices. An imaging system recorded selected temperature (Tsel ) within the gradient every 5 sec. Acute 2.25 and 2.60 g ethanol/kg produced significantly lower Tj than NaCI. 2.60 g/kg also produced significantly lower Tsel than 2.25 g/kg or NaCI. 2.75 g/kg and above incapacitated mice. Comparison of responses using a thermoregulatory index indicated 2.25 or 2.60 g/kg decreased the regulated temperature. Similar methodology was followed using the selected lines and 10% ethanol (2.0, 2.25, 2.65 g/kg to COLD mice; 2.65, 2.85 g/kg to HOT mice; 3.0 g/kg to HOT2 mice) or NaCI. All responded similarly to NaCl, with transient rise in Tj After an effective ethanol dose mice manifested a regulated decrease in Tj by lowering Tsel concomitant with falling Tj . In both replicate pairs COLD mice were more sensitive than HOT, indicating that a true difference in the CNS regulator of body temperature was selected for in these animals. Photoperiod effect was characterized by quantifying thermoregulatory behavior of COLD2 mice after acute 2.60 g 7.5% ethanol/kg or NaCl, at 0400 , 0800 , 1200, 1600 , 2000 and 2400 hours , using above methodology. Baseline T₁ was significantly lower during hours of light, than during darkness. Photoperiod had little effect on thermoregulatory response to ethanol, possibly because of arousal associated with experiments. Thermoregulatory tolerance to ethanol was investigated using HS mice implanted with telemetry devices and monitored in the gradient on days 1, 2, 4, 7 and 11 of 11 consecutive days of 10% ethanol (2.75 g/kg) or NaCl injections. Dispositional, rapid and chronic tolerance developed, indicating that functional tolerance is a regulated phenomenon in mice. In a separate experiment HS mice were implanted with telemetry devices and injected with ethanol for 11 consecutive days at constant temperature; dispositional but not functional tolerance developed. To characterize thermoregulation during withdrawal, HS mice were made dependent upon ethanol using a vapor chamber; T; Tsel and activity were monitored in the gradient until 26 hours post withdrawal. Withdrawing mice showed unaltered regulated temperature, but lower Tsel than controls. This suggested increased metabolic heat production. Thermoregulation during withdrawal was similarly studied using the selected mouse lines. COLD mice responded like HS mice. Withdrawing HOT1 mice were more active than controls; withdrawing HOT2 mice showed lowest Tsel of any genotype but maintained Ti above controls. These results suggest a more severe withdrawal reaction in HOT, than in COLD mice. To investigate a possible mechanism underlying ethanol hypothermia, responses of HOT and COLD mice to intracerebroventricular serotonin were characterized. Dose-dependent decreases in Tre were measured in mice equipped with indwelling brain cannulae and held at constant temperature after injection of 0.3, 0.8, 2.0, 5.0 or 11.0 μg serotonin into the lateral brain ventricle. COLD mice were significantly more sensitive than HOT mice. Subsequently HOT1 and COLD1 mice were equipped with brain cannulae and implanted telemetry devices; thermoregulatory behavior after 11.0 μg serotonin was monitored. Both genotypes lowered Tj significantly more in the gradient than did similar mice at constant ambient temperature, indicating that decline in Tj after serotonin was a regulated phenomenon. The serotonergic system was altered during selection for differential Tre response to ethanol, indicating a role for serotonin in mediating ethanol hypothermia. Title: Thermoregulation in Mice under the Influence of Ethanol Author: O'Connor, Candace Sharon Year: 1993 Thermoregulation after acute ethanol, during chronic exposure and during withdrawal from ethanol dependency was studied using genetically heterogeneous (HS) mice, and lines of mice selected in replicate for smaller (HOT1, HOT2) or greater (COLD1, COLD2) decline in rectal temperature (Tre ) after intraperitoneal ethanol. First, HS mice were injected with 20% ethanol in 0.9% NaCI, or NaCI alone during sessions of behavioral thermoregulation in individual temperature gradients (9-38°C). Internal temperature (Tj ) was monitored with implanted telemetry devices. An imaging system recorded selected temperature (Tsel ) within the gradient every 5 sec. Acute 2.25 and 2.60 g ethanol/kg produced significantly lower Tj than NaCI. 2.60 g/kg also produced significantly lower Tsel than 2.25 g/kg or NaCI. 2.75 g/kg and above incapacitated mice. Comparison of responses using a thermoregulatory index indicated 2.25 or 2.60 g/kg decreased the regulated temperature. Similar methodology was followed using the selected lines and 10% ethanol (2.0, 2.25, 2.65 g/kg to COLD mice; 2.65, 2.85 g/kg to HOT mice; 3.0 g/kg to HOT2 mice) or NaCI. All responded similarly to NaCl, with transient rise in Tj After an effective ethanol dose mice manifested a regulated decrease in Tj by lowering Tsel concomitant with falling Tj . In both replicate pairs COLD mice were more sensitive than HOT, indicating that a true difference in the CNS regulator of body temperature was selected for in these animals. Photoperiod effect was characterized by quantifying thermoregulatory behavior of COLD2 mice after acute 2.60 g 7.5% ethanol/kg or NaCl, at 0400 , 0800 , 1200, 1600 , 2000 and 2400 hours , using above methodology. Baseline T₁ was significantly lower during hours of light, than during darkness. Photoperiod had little effect on thermoregulatory response to ethanol, possibly because of arousal associated with experiments. Thermoregulatory tolerance to ethanol was investigated using HS mice implanted with telemetry devices and monitored in the gradient on days 1, 2, 4, 7 and 11 of 11 consecutive days of 10% ethanol (2.75 g/kg) or NaCl injections. Dispositional, rapid and chronic tolerance developed, indicating that functional tolerance is a regulated phenomenon in mice. In a separate experiment HS mice were implanted with telemetry devices and injected with ethanol for 11 consecutive days at constant temperature; dispositional but not functional tolerance developed. To characterize thermoregulation during withdrawal, HS mice were made dependent upon ethanol using a vapor chamber; T; Tsel and activity were monitored in the gradient until 26 hours post withdrawal. Withdrawing mice showed unaltered regulated temperature, but lower Tsel than controls. This suggested increased metabolic heat production. Thermoregulation during withdrawal was similarly studied using the selected mouse lines. COLD mice responded like HS mice. Withdrawing HOT1 mice were more active than controls; withdrawing HOT2 mice showed lowest Tsel of any genotype but maintained Ti above controls. These results suggest a more severe withdrawal reaction in HOT, than in COLD mice. To investigate a possible mechanism underlying ethanol hypothermia, responses of HOT and COLD mice to intracerebroventricular serotonin were characterized. Dose-dependent decreases in Tre were measured in mice equipped with indwelling brain cannulae and held at constant temperature after injection of 0.3, 0.8, 2.0, 5.0 or 11.0 μg serotonin into the lateral brain ventricle. COLD mice were significantly more sensitive than HOT mice. Subsequently HOT1 and COLD1 mice were equipped with brain cannulae and implanted telemetry devices; thermoregulatory behavior after 11.0 μg serotonin was monitored. Both genotypes lowered Tj significantly more in the gradient than did similar mice at constant ambient temperature, indicating that decline in Tj after serotonin was a regulated phenomenon. The serotonergic system was altered during selection for differential Tre response to ethanol, indicating a role for serotonin in mediating ethanol hypothermia. Close

• 3. [Article] The metabolic cost of behavioral thermoregulation of body temperature in the northern alligator lizard Gerrhonotus coeruleus, and how it affects the classical concept of eurythermality

  The effect of total metabolic cost expenditures on the precision of behavioral thermoregulation was investigated for the purportedly eurythermic Northern Alligator lizard (Gerrhonotus coeruleus). An operant ...

  Citation × Citation Citation Abstract Copy Title: The metabolic cost of behavioral thermoregulation of body temperature in the northern alligator lizard Gerrhonotus coeruleus, and how it affects the classical concept of eurythermality Author: Campbell, James Dudley Year: 1981 The effect of total metabolic cost expenditures on the precision of behavioral thermoregulation was investigated for the purportedly eurythermic Northern Alligator lizard (Gerrhonotus coeruleus). An operant apparatus was designed to test metabolic output at different heat reinforcement magnitudes. The mean TB reflected in each trial was positively correlated to the length of reinforcement. The shuttle rate during each trial was inversely correlated to the length of reinforcement. The standard deviation and total metabolic costs did not vary significantly between trials undertaken at the same ambient temperature. Eurythermality in G. coeruleus is caused by fluctuations in preferred body temperature and not by fluctuations around this temperature. The metabolic cost of behavioral thermoregulation did not change with corresponding changes in reinforcement magnitude. This indicates that eurythermality is the recorded effect of lizards behaviorally regulating to different TB in a stenothermic manner, rather than of random TB fluctuations in a wide range of normal activity (the classical view of eurythermality). Title: The metabolic cost of behavioral thermoregulation of body temperature in the northern alligator lizard Gerrhonotus coeruleus, and how it affects the classical concept of eurythermality Author: Campbell, James Dudley Year: 1981 The effect of total metabolic cost expenditures on the precision of behavioral thermoregulation was investigated for the purportedly eurythermic Northern Alligator lizard (Gerrhonotus coeruleus). An operant apparatus was designed to test metabolic output at different heat reinforcement magnitudes. The mean TB reflected in each trial was positively correlated to the length of reinforcement. The shuttle rate during each trial was inversely correlated to the length of reinforcement. The standard deviation and total metabolic costs did not vary significantly between trials undertaken at the same ambient temperature. Eurythermality in G. coeruleus is caused by fluctuations in preferred body temperature and not by fluctuations around this temperature. The metabolic cost of behavioral thermoregulation did not change with corresponding changes in reinforcement magnitude. This indicates that eurythermality is the recorded effect of lizards behaviorally regulating to different TB in a stenothermic manner, rather than of random TB fluctuations in a wide range of normal activity (the classical view of eurythermality). Close

• 4. [Article] Effect of ethanol on thermoregulation in the goldfish, Carassius auratus

  In an attempt to elucidate the mechanism by which ethanol affects vertebrate thermoregulation, the effect of ethanol on temperature selection was studied in the goldfish, Carassius auratus. Ethanol was ...

  Citation × Citation Citation Abstract Copy Title: Effect of ethanol on thermoregulation in the goldfish, Carassius auratus Author: O'Connor, Candace Sharon Year: 1986 In an attempt to elucidate the mechanism by which ethanol affects vertebrate thermoregulation, the effect of ethanol on temperature selection was studied in the goldfish, Carassius auratus. Ethanol was administered to 10 to 15 g fish by mixing it in the water of a temperature gradient. The dose response curve was very steep between 0.5% (v/v) ethanol (no response) and 0.7% (significant lowering of selected temperature in treated fish). Fish were exposed to concentrations of ethanol as high as 1.7%, at which concentration most experimental fish lost their ability to swim upright in the water. At concentrations higher than 0.7%, the magnitude of the effect did not increase with increasing concentration of ethanol; treated animals continued to select temperatures about 2 C below temperatures selected by controls. Experiments alternating exposure to 1.0% ethanol and water showed that the rate of onset and disappearance of the ethanol effect was rapid (within 10 min). Other experiments exposing fish to 1.0% ethanol for up to 3 hr showed that the effect remained stable for this period of time. The thermoregulatory responses of fish are behavioral, and therefore relatively easy to observe and quantify. Ethanol produces a prompt, stable and reproducible depression of selected temperature in the goldfish. Because the temperature at which fish regulate is controlled by a central nervous system set point and not altered by effects on peripheral effector systems, it appears that ethanol may cause hypothermia in goldfish by directly acting to lower the set point. Title: Effect of ethanol on thermoregulation in the goldfish, Carassius auratus Author: O'Connor, Candace Sharon Year: 1986 In an attempt to elucidate the mechanism by which ethanol affects vertebrate thermoregulation, the effect of ethanol on temperature selection was studied in the goldfish, Carassius auratus. Ethanol was administered to 10 to 15 g fish by mixing it in the water of a temperature gradient. The dose response curve was very steep between 0.5% (v/v) ethanol (no response) and 0.7% (significant lowering of selected temperature in treated fish). Fish were exposed to concentrations of ethanol as high as 1.7%, at which concentration most experimental fish lost their ability to swim upright in the water. At concentrations higher than 0.7%, the magnitude of the effect did not increase with increasing concentration of ethanol; treated animals continued to select temperatures about 2 C below temperatures selected by controls. Experiments alternating exposure to 1.0% ethanol and water showed that the rate of onset and disappearance of the ethanol effect was rapid (within 10 min). Other experiments exposing fish to 1.0% ethanol for up to 3 hr showed that the effect remained stable for this period of time. The thermoregulatory responses of fish are behavioral, and therefore relatively easy to observe and quantify. Ethanol produces a prompt, stable and reproducible depression of selected temperature in the goldfish. Because the temperature at which fish regulate is controlled by a central nervous system set point and not altered by effects on peripheral effector systems, it appears that ethanol may cause hypothermia in goldfish by directly acting to lower the set point. Close