Influence of Time of Day on Body Temperature, Heart Rate, Arterial Pressure, and Other Biological Variables in Horses during Incremental Exercise

Physiological responses to anesthetic doses of four chemically dissimilar agents, namely, Althesin, urethane, chloralose-urethane, and pentobarbital sodium were compared in rats. The tail-flick test revealed Althesin had greater antinociceptive potency than urethane, chloralose-urethane, and pentobarbital, but its duration of action was shorter than that of chloralose-urethane. Althesin produced minimal or no suppression of core body temperature and mean arterial pressure, and only moderate reduction of mean pulse pressure. The heart rate and respiratory rate of Althesin-treated rats were slower than those of chloralose-urethane and urethane-treated counterparts, respectively, but were not significantly decreased from normal controls. It is concluded that Althesin is a suitable anesthetic for short-term surgery and for studies of body temperature, heart rate, and mean arterial pressure. Because release of gonadotropin-releasing hormone into hypophysial portal blood can be observed under Althesin but is suppressed or blocked by chloralose-urethane, urethane, and pentobarbital, Althesin is the anesthetic of choice in studies concerned with the neural control of ovulatory hormone release.

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The effects of age, sex, body temperature, heart rate, and time of day on the perception of time in life

Time & Society ◽

10.1177/0961463x13479187 ◽

2013 ◽

Vol 23 (2) ◽

pp. 195-211 ◽

Cited By ~ 4

Author(s):

PA Hancock ◽

GM Hancock

Keyword(s):

Heart Rate ◽

Body Temperature ◽

Time Of Day ◽

Perception Of Time

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Hypothyroid-induced changes in autonomic control have a central serotonergic component

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1997.272.2.h894 ◽

1997 ◽

Vol 272 (2) ◽

pp. H894-H903 ◽

Cited By ~ 1

Author(s):

W. N. Henley ◽

F. Vladic

Keyword(s):

Heart Rate ◽

Mean Arterial Pressure ◽

Body Temperature ◽

Arterial Pressure ◽

Pulse Pressure ◽

Pressor Response ◽

Autonomic Control ◽

Serotonergic Activity ◽

Induced Changes ◽

Elevated Heart Rate

Three experiments were conducted in unanesthetized rats made hypothyroid (Hypo) or maintained as euthyroid controls (Eu) to examine general cardiovascular responsiveness [experiment I (Exp I)]; responsiveness to a serotonin (5-HT2) agonist, dl-2,5-dimethoxy-4-iodoamphetamine [DOI intracerebroventricularly; experiment II (Exp II)]; or responsiveness to a 5-HT(1A) agonist dl-8-hydroxydipropyl-aminotetralin hydrobromide [8-OH-DPAT intracerebroventricularly; experiment III (Exp III)]. In Exp I, intravenous infusions of phenylephrine and nitroprusside provided little evidence that findings in Exp II and III were caused by generalized impairment in cardiovascular responsiveness in Hypo. In Exp II and III, Eu and Hypo were given either intra-arterial atropine or vehicle. Atropine significantly elevated heart rate (Exp II and III) and mean arterial pressure (Exp II) in Eu only. When compared with Eu, Hypo had a reduced pressor response (5.2 vs. 20.1%), an attenuated pulse pressure response (19.3 vs. 35.4%), and a more robust bradycardia (-17.7 vs. -7.0%) in response to DOI. These differences were atropine sensitive. In Exp III, Hypo had larger decrements in mean arterial pressure (-9.0 vs. -5.1%), heart rate ( -13.9 vs. - 7.7%), and body temperature (-4.5 vs. -2.7%) in response to 8-OH-DPAT in comparison to Eu. Parasympathetic involvement in the differential responses to 8-OH-DPAT was less clear than with DOI. Deranged autonomic control in hypothyroidism may be caused, in part, by changes in central serotonergic activity.

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Monitoring heart rate and body temperature in red foxes (Vulpes vulpes)

Canadian Journal of Zoology ◽

10.1139/z89-346 ◽

1989 ◽

Vol 67 (10) ◽

pp. 2455-2458 ◽

Cited By ~ 12

Author(s):

Terry J. Kreeger ◽

Daniel Monson ◽

Valerian B. Kuechle ◽

Ulysses S. Seal ◽

John R. Tester

Keyword(s):

Heart Rate ◽

Body Temperature ◽

Radio Signal ◽

Time Of Day ◽

Video Tape ◽

Red Foxes ◽

Sinus Arrhythmia ◽

Level Of Activity ◽

Significant Difference ◽

And Behavior

Twenty-four captive-raised red foxes were surgically implanted with radios that transmitted both heart rate and body temperature. Successive fox pairs were placed in a 4.1-ha observation pen for 2 weeks and behavior was video recorded. The radio signal was recorded on the audio portion of the video tape for computer decoding. Heart rate and body temperature were measured for six behavior categories: sleeping, awake, hunting, feeding, running, and being chased. The heart rate for each of these categories was significantly different from any other (P = 0.0001). All body temperature categories were different from each other except for running and being chased (P = 0.0001). Both heart rate and body temperature increased with level of activity. The only significant difference in heart rate and body temperature between sexes was for the sleeping heart rate category, where females had higher values than males (P = 0.04). There was also a significant time of day effect showing that body temperature while awake was highest at night (P = 0.0005). Sleeping foxes displayed a pronounced sinus arrhythmia which disappeared when they became active.

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Time-of-day-dependent effects of bright light exposure on human psychophysiology: comparison of daytime and nighttime exposure

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00121.2005 ◽

2006 ◽

Vol 290 (5) ◽

pp. R1413-R1420 ◽

Cited By ~ 136

Author(s):

Melanie Rüger ◽

Marijke C. M. Gordijn ◽

Domien G. M. Beersma ◽

Bonnie de Vries ◽

Serge Daan

Keyword(s):

Heart Rate ◽

Body Temperature ◽

Light Exposure ◽

Core Body Temperature ◽

Bright Light ◽

Time Of Day ◽

Wide Field ◽

Young Males ◽

Core Body ◽

Bright Light Exposure

Bright light can influence human psychophysiology instantaneously by inducing endocrine (suppression of melatonin, increasing cortisol levels), other physiological changes (enhancement of core body temperature), and psychological changes (reduction of sleepiness, increase of alertness). Its broad range of action is reflected in the wide field of applications, ranging from optimizing a work environment to treating depressed patients. For optimally applying bright light and understanding its mechanism, it is crucial to know whether its effects depend on the time of day. In this paper, we report the effects of bright light given at two different times of day on psychological and physiological parameters. Twenty-four subjects participated in two experiments ( n = 12 each). All subjects were nonsmoking, healthy young males (18–30 yr). In both experiments, subjects were exposed to either bright light (5,000 lux) or dim light <10 lux (control condition) either between 12:00 P.M. and 4:00 P.M. ( experiment A) or between midnight and 4:00 A.M. ( experiment B). Hourly measurements included salivary cortisol concentrations, electrocardiogram, sleepiness (Karolinska Sleepiness Scale), fatigue, and energy ratings (Visual Analog Scale). Core body temperature was measured continuously throughout the experiments. Bright light had a time-dependent effect on heart rate and core body temperature; i.e., bright light exposure at night, but not in daytime, increased heart rate and enhanced core body temperature. It had no significant effect at all on cortisol. The effect of bright light on the psychological variables was time independent, since nighttime and daytime bright light reduced sleepiness and fatigue significantly and similarly.

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