Melatonin and thermoregulation in ectothermic vertebrates: a review

2003 ◽  
Vol 81 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Deborah I Lutterschmidt ◽  
William I Lutterschmidt ◽  
Victor H Hutchison
Keyword(s):  
Body Temperature ◽  
Pineal Gland ◽  
Behavioral Thermoregulation ◽  
Review Of The Literature ◽  
Thermoregulatory Behavior ◽  
Pineal Complex ◽  
Set Point ◽  
Environmental Stimuli ◽  
Interspecific Differences

Precise behavioral thermoregulation is well documented in many ectothermic vertebrates. However, many complexities involving the influence of the pineal gland and melatonin (MEL) on thermoregulatory behavior, and thus body temperature (Tb), remain unresolved. Although MEL is commonly considered to decrease Tb in both endotherms and ectotherms, several ectothermic species do not modulate Tb in response to MEL. Furthermore, it is not yet clear how MEL integrates thermoregulatory behavior with environmental stimuli or how it modulates Tb. Some inferences about MEL action in endotherms are not applicable to ectotherms. Changes in ectothermic Tb are mediated primarily through behavioral modulation (not physiological modulation as in endotherms). Thus, the most likely mechanism underlying MEL's actions on ectothermic Tb is adjustment of the temperature set point in the hypothalamus. We provide a review of the literature addressing the effects of MEL on thermoregulatory behavior in ectothermic vertebrates. We also discuss mechanisms underlying MEL's influence on physiological and behavioral processes in ectotherms and hypotheses regarding interspecific differences in pineal complex and MEL function.

Indomethacin impairs LPS-induced behavioral fever in toads

2002 ◽  
Vol 93 (2) ◽  
pp. 512-516 ◽  
Author(s):  
K. C. Bicego ◽  
A. A. Steiner ◽  
J. Antunes-Rodrigues ◽  
L. G. S. Branco
Keyword(s):  
Body Temperature ◽  
Thermal Gradient ◽  
Behavioral Thermoregulation ◽  
Cyclooxygenase Inhibitor ◽  
Set Point ◽  
Behavioral Fever ◽  
Preferred Body Temperature ◽  
Baseline Values ◽  
Toad Bufo

We tested the hypothesis that PGs mediate lipopolysaccharide (LPS)-induced behavioral fever in the toad Bufo paracnemis. Measurements of preferred body temperature (Tb) were performed with a thermal gradient. Toads were injected intraperitoneally with the cyclooxygenase inhibitor indomethacin (5 mg/kg), which inhibits PG biosynthesis, or its vehicle (Tris) followed 30 min later by LPS (0.2 and 2 mg/kg) into the lymph sac. LPS at the dose of 0.2 mg/kg caused a significant increase in Tb from 7 to 10 h after injection, and then Tb returned toward baseline values. LPS at the dose of 2 mg/kg produced a different pattern of response, with a longer latency to the onset of fever (10th h) and a longer duration (until the end of the experiment at the 15th h). Tris significantly attenuated the fever induced by LPS at 0.2 mg/kg, but not at 2 mg/kg. Moreover, indomethacin completely blocked the fever evoked by LPS (2 mg/kg). These results indicate that the behavioral fever induced by LPS in toads requires the activation of the COX pathway, suggesting that the involvement of PG in fever has an ancient phylogenetic history and that endogenous PGs raise the thermoregulatory set point to produce fever, because behavioral thermoregulation seems to be related to changes in the thermoregulatory set point.

24-hour control of body temperature in rats. I. Integration of behavioral and autonomic effectors

1994 ◽  
Vol 267 (1) ◽  
pp. R71-R77 ◽  
Author(s):  
C. J. Gordon
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Behavioral Thermoregulation ◽  
Gradient System ◽  
Dark Phase ◽  
Light Phase ◽  
Set Point ◽  
Selection Of ◽  
Dark Transition

Some studies suggest that the nocturnal elevation in core temperature (Tc) of the rat is mediated by an elevation in the set point. The role of set point can be assessed if behavioral effectors are measured simultaneously with other thermoregulatory effectors and Tc over a 24-h period. Selected ambient temperature (STa) and motor activity (MA) were measured in rats housed in a temperature gradient system with a 12:12-h photoperiod (lights on 0600 h). Tc and heart rate (HR) were monitored by telemetry. During the light phase, STa, Tc, HR, and MA were relatively stable with values 29.0 degrees C, 37.1 degrees C, 310 beats/min, and 1-2 m/h, respectively. During the light-to-dark transition there were abrupt elevations in Tc, HR, and MA but no change in STa. STa decreased during the dark phase and reached a nadir of 23 degrees C at 0500 h. All variables recovered to basal levels within 3-4 h after the onset of the light phase. Overall, autonomic effectors control the elevation in Tc during the onset of the dark phase while behavioral effectors have little if any role. Behavioral thermoregulation is important in two ways: 1) the selection of cooler Ta values at night to prevent an excess elevation in Tc and 2) a preference for cooler Ta values before the light phase to facilitate the recovery of Tc.

Comparative effects of hypoxia on behavioral thermoregulation in rats, hamsters, and mice

1991 ◽  
Vol 260 (1) ◽  
pp. R120-R125 ◽  
Author(s):  
C. J. Gordon ◽  
L. Fogelson
Keyword(s):  
Statistical Analysis ◽  
Body Temperature ◽  
Temperature Gradient ◽  
Sample Size ◽  
Oxygen Content ◽  
Rodent Species ◽  
Behavioral Thermoregulation ◽  
Body Temperatures ◽  
Set Point ◽  
Deep Body

Recent studies using reptiles and other ectothermic species have shown that hypoxia lowers the set point for the control of body temperature. This is characterized by a preference for cooler ambient (Ta) and deep body temperatures (Tb) when placed in a temperature gradient. To elucidate the presence of this effect in mammals, the selected Ta and Tb of three rodent species (mouse, hamster, and rat) were measured while subjected to graded hypoxia in a temperature gradient. Individual animals were placed in the gradient for 30 min. Oxygen content of air entering the gradient was then reduced to a constant level for a period of 60 min by dilution with nitrogen. Tb was significantly reduced in all species at %O2 levels of 5.5-10%. Selected Ta was significantly reduced in the mouse at %O2 levels of 5.5 and 7.3%. Selected Ta of the hamster and rat were reduced slightly at %O2 levels of 5.8 and 7.4%, respectively; however, the effect was not statistically significant. To clarify the effects of hypoxia in these two species, the sample size of rat and hamster was increased to strengthen statistical analysis, and the animals were exposed for 60 min to %O2 levels of 7.4 and 6.7%, respectively. Both species exhibited a significant reduction in selected Ta during hypoxia concomitant with hypothermia. These data support the hypothesis that hypoxia lowers the set point for the control of body temperature in rodents.

scholarly journals The Impact of Central and Peripheral Cyclooxygenase Enzyme Inhibition on Exercise-Induced Elevations in Core Body Temperature

2017 ◽  
Vol 12 (5) ◽  
pp. 662-667 ◽  
Author(s):  
Matthijs T.W. Veltmeijer ◽  
Dineke Veeneman ◽  
Coen C.C.W. Bongers ◽  
Mihai G. Netea ◽  
Jos W. van der Meer ◽  
...  
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Skin Temperature ◽  
Core Body Temperature ◽  
Exercise Tests ◽  
Hypothalamic Temperature ◽  
Set Point ◽  
Exercise Induced ◽  
Core Body ◽  
The Impact

Purpose:Exercise increases core body temperature (TC) due to metabolic heat production. However, the exercise-induced release of inflammatory cytokines including interleukin-6 (IL-6) may also contribute to the rise in TC by increasing the hypothalamic temperature set point. This study investigated whether the exercise-induced increase in TC is partly caused by an altered hypothalamic temperature set point.Methods:Fifteen healthy, active men age 36 ± 14 y were recruited. Subjects performed submaximal treadmill exercise in 3 randomized test conditions: (1) 400 mg ibuprofen and 1000 mg acetaminophen (IBU/APAP), (2) 1000 mg acetaminophen (APAP), and (3) a control condition (CTRL). Acetaminophen and ibuprofen were used to block the effect of IL-6 at a central and peripheral level, respectively. TC, skin temperature, and heart rate were measured continuously during the submaximal exercise tests.Results:Baseline values of TC, skin temperature, and heart rate did not differ across conditions. Serum IL-6 concentrations increased in all 3 conditions. A significantly lower peak TC was observed in IBU/APAP (38.8°C ± 0.4°C) vs CTRL (39.2°C ± 0.5°C, P = .02) but not in APAP (38.9°C ± 0.4°C) vs CTRL. Similarly, a lower ΔTC was observed in IBU/APAP (1.7°C ± 0.3°C) vs CTRL (2.0°C ± 0.5°C, P < .02) but not in APAP (1.7°C ± 0.5°C) vs CTRL. No differences were observed in skin temperature and heart-rate responses across conditions.Conclusions:The combined administration of acetaminophen and ibuprofen resulted in an attenuated increase in TC during exercise compared with a CTRL. This observation suggests that a prostaglandin-E2-induced elevated hypothalamic temperature set point may contribute to the exercise-induced rise in TC.

scholarly journals Atypical pleomorphic neoplasms of the pineal gland: Case report and review of the literature

2015 ◽  
Vol 6 (1) ◽  
pp. 129
Author(s):  
M Praver ◽  
R D′Amico ◽  
C Arraez ◽  
BE Zacharia ◽  
H Varma ◽  
...  
Keyword(s):  
Case Report ◽  
Pineal Gland ◽  
Review Of The Literature

scholarly journals Short-term changes in air humidity and water availability weakly constrain thermoregulation in a dry-skinned ectotherm

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247514
Author(s):  
Jean-François Le Galliard ◽  
David Rozen-Rechels ◽  
Anjélica Lecomte ◽  
Clémence Demay ◽  
Andréaz Dupoué ◽  
...  
Keyword(s):  
Body Temperature ◽  
Water Availability ◽  
Behavioral Thermoregulation ◽  
Thermal Preference ◽  
Air Humidity ◽  
Short Term ◽  
Free Standing ◽  
Standing Water ◽  
Zootoca Vivipara ◽  
Thermal Preferences

Thermoregulation is critical for ectotherms as it allows them to maintain their body temperature close to an optimum for ecological performance. Thermoregulation includes a range of behaviors that aim at regulating body temperature within a range centered around the thermal preference. Thermal preference is typically measured in a thermal gradient in fully-hydrated and post-absorptive animals. Short-term effects of the hydric environment on thermal preferences in such set-ups have been rarely quantified in dry-skinned ectotherms, despite accumulating evidence that dehydration might trade-off with behavioral thermoregulation. Using experiments performed under controlled conditions in climatic chambers, we demonstrate that thermal preferences of a ground-dwelling, actively foraging lizard (Zootoca vivipara) are weakly decreased by a daily restriction in free-standing water availability (less than 0.5°C contrast). The influence of air humidity during the day on thermal preferences depends on time of the day and sex of the lizard, and is generally weaker than those of of free-standing water (less than 1°C contrast). This shows that short-term dehydration can influence, albeit weakly, thermal preferences under some circumstances in this species. Environmental humidity conditions are important methodological factors to consider in the analysis of thermal preferences.

Pineal Apoplexy: A Case Series and Review of the Literature

2021 ◽  
Author(s):  
Martin Majovsky ◽  
David Netuka ◽  
Radim Lipina ◽  
Jan Mraček ◽  
Vladimír Beneš
Keyword(s):  
Surgical Treatment ◽  
Pineal Gland ◽  
Clinical Significance ◽  
Obstructive Hydrocephalus ◽  
Case Series ◽  
Surgical Removal ◽  
Pineal Tumor ◽  
Review Of The Literature ◽  
Melatonin Secretion ◽  
Pubmed Database

Abstract Background Pineal apoplexy is a rare condition, with unknown incidence and clinical significance. To elucidate this clinical condition, we analyzed our own case series and performed a review of the literature. Methods We enrolled all patients with a hemorrhagic pineal apoplexy who were referred to our department between January 2000 and January 2020. Hemorrhagic pineal apoplexy was defined as the presence of fluid–fluid levels inside the pineal cyst (PC) on an axial or sagittal magnetic resonance scan. In one patient, after PC apoplexy, we performed a circadian melatonin sampling from peripheral blood to determine the function of the pineal gland. The PubMed database was searched for publications using the terms “pineal” and “apoplexy.” Results Eight patients were enrolled, of which three patients underwent surgical treatment and five patients were managed conservatively. One patient was tested for circadian melatonin secretion. Results confirmed melatonin secretion with preserved physiologic circadian rhythm.Our search of the literature led us to 31 studies that comprised 30 patients with apoplectic PC, 9 with apoplectic pineal tumor, and 1 with bleeding into the normal pineal gland. Most patients presented with headache, nausea, and vomiting, less frequently with acute hydrocephalus and gaze palsy. Twenty patients with a PC underwent resection or aspiration. Two patients underwent shunt placement as the only procedure and five received both shunt and surgical removal. Six patients with a PC were observed without surgical treatment. All the nine patients with a pineal tumor were operated on. In indicated cases, four patients received radiation therapy and one received chemotherapy. Conclusion Clinical significance of hemorrhagic pineal apoplexy ranges from an asymptomatic course to rapid deterioration and death. In patients with mild symptoms, observation is indicated, whereas surgical treatment is reserved for severe cases presenting with obstructive hydrocephalus and includes cerebrospinal fluid diversion, resection of apoplectic pineal lesions, or both.

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