Single injections of triazolam, a short-acting benzodiazepine, lengthen the period of the circadian activity rhythm in golden hamsters

Joy, Janet E.; Losee-Olson, Susan; Turek, Fred W.

doi:10.1007/bf01954855

Cited by 33 publications

(10 citation statements)

References 18 publications

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“…Long-term alterations in free-running period following acute stimulation have been reported previously for photic (Pittendrigh and Daan, 1976), pharmacological (Joy et al, 1989;Edgar et al, 1993;Meyer et al, 1993), and arousal-related stimuli (Mrosovsky, 1993). In the present study, we noted a tendency for phase delays to be associated with period lengthening and for phase advances to be associated with period shortening, for both clonidine and saline treatments.…”

Section: Discussionsupporting

confidence: 55%

“…A similar relationship between phase shift and period change has been noted previously in studies of photic phase shifting (Pittendrigh and Daan, 1976), but the results for non-photic phase shifting are inconsistent. For example, both triazolam and induced activity are associated with period lengthening (Joy et al, 1989;Mrosovsky, 1993), while serotonergic agonists are associated with period shortening . These effects are not systematically related to phase shift magnitude or direction, but were related to circadian time, showing "period-response" curves quite different from the corresponding PRCs.…”

Section: Discussionmentioning

confidence: 98%

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Circadian phase shifting induced by clonidine injections in Syrian hamsters

Rosenwasser

Vogt

Pellowski

1995

Biological Rhythm Research

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The mammalian circadian pacemaker can be phase shifted by photic, pharmacological, and behaviorally-derived stimuli. The phase-response curves (PRCs) characterizing these diverse stimuli may comprise two distinct families; a photic PRC typified by the response to brief light pulses, and a nonphotic PRC, typified by the response to dark pulses and to behavioral activation. The present study examined the phase shifting effects of acute systemic treatment with the alpha2-adrenoceptor agonist, clonidine, in Syrian hamsters. Clonidine injections (0.25 mg/kg, ip) delivered during subjective night mimicked the phase shifting effects of light pulses in animals housed in both constant darkness (DD) and constant red light (RR), but similar effects were not seen in saline-treated controls. Both clonidine and saline injections resulted in phase advances during subjective day, but only in RRhoused animals. Clonidine-induced phase shifting was dose-dependent, but rather high doses were required to induce phase shifts. Pretreatment with the selective noradrenergic neurotoxin, DSP-4, blocked clonidine-induced phase shifting. These results suggest that clonidine acts at presynaptic alpha2-adrenergic autoreceptors to disinhibit spontaneous and/or evoked activity in the photic entrainment pathway.

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Section: Discussionsupporting

confidence: 55%

Section: Discussionmentioning

confidence: 98%

Circadian phase shifting induced by clonidine injections in Syrian hamsters

Rosenwasser

Vogt

Pellowski

1995

Biological Rhythm Research

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“…Locomotor activity has previously been shown to influence the circadian period in nocturnal rodent species (Edgar et al, 1991a;Joy et al, 1989;Mrosovsky, 1993;Weisgerber et al, 1997;Yamada et al, 1988). The extent to which period changes reflect daily nonphotic phase shifts or direct effects on the period of the endogenous circadian pacemaker is not always clear.…”

Section: Discussionmentioning

confidence: 98%

Scheduled Voluntary Wheel Running Activity Modulates Free-Running Circadian Body Temperature Rhythms in Octodon degus

Kas

Edgar

2001

J Biol Rhythms

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Entrainment of the circadian pacemaker to nonphotic stimuli, such as scheduled wheel-running activity, is well characterized in nocturnal rodents, but little is known about activity-dependent entrainment in diurnal or crepuscular species. In the present study, effects of scheduled voluntary wheel-running activity on circadian timekeeping were investigated in Octodon degus, a hystricomorph rodent that exhibits robust crepuscular patterns of wakefulness. When housed in constant darkness, O. degus exhibited circadian rhythms in wheel-running activity and body temperature (Tb) with an average period length (tau) of 23.39 +/- 0.11 h. When wheel running was restricted to a fixed 2-h schedule every 24 h, tau increased on average 0.39 +/- 0.09 h but did not result in steady-state entrainment. Instead, relative coordination between the fixed running schedule and circadian timing was observed. Tau was greatest when scheduled wheel running occurred at CT 20.5 (0.4 h greater than DD baseline tau). Scheduled running activity also influenced Tb waveform symmetry, reflecting concomitant changes in the circadian activity-rest ratio (alpha:rho). Aftereffects of the scheduled wheel-running paradigm were also observed. In 2 animals, tau lengthened from 23.20 and 23.80 h to 24.14 and 24.15 h, respectively, and remained relatively stable for approximately 1 month during the wheel schedule. Although behavioral activity appears to be a weak zeitgeber in this species, these data suggest that nonphotic stimuli can phase delay the circadian pacemaker in O. degus at similar times of the day as in nocturnal hamsters and mice, and in humans.

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“…Animal studies have shown that increased levels of physical activity are associated with changes in the period (Aschoff et al, 1973;Edgar et al, 1991;Gnaedinger and Rosenberg, 1992;Honma et al, 1991;Joy et al, 1989;Mrosovsky, 1993), phase (Janik and Mrosovsky, 1993;Joy et al,1989;Mrosovsky, 1991;Mrosovsky and Biello, 1994;Turek et al, 1995;Van Reeth et al, 1992), and entrainment (Mrosovsky and Salmon, 1987;Reebs and Mrosovsky, 1989;Turek et al, 1995;Van Reeth et al, 1993) of circadian rhythms. In humans, a large number of studies suggests that increased physical fitness improves both daytime performance and nighttime sleep, but its effect on circadian rhythms has received very little attention (Van Someren et al, 1994).…”

Section: Introductionmentioning

confidence: 97%

Long-Term Fitness Training Improves the Circadian Rest-Activity Rhythm in Healthy Elderly Males

et al. 1997

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In old age, the circadian timing system loses optimal functioning. This process is even accelerated in Alzheimer's disease. Because pharmacological treatment of day-night rhythm disturbances usually is not very effective and may have considerable side effects, nonpharmacological treatments deserve attention. Bright light therapy has been shown to be effective. It is known from animal studies that increased activity, or an associated process, also strongly affects the circadian timing system, and the present study addresses the question of whether an increased level of physical activity may improve circadian rhythms in elderly. In the study, 10 healthy elderly males were admitted to a fitness training program for 3 months. The circadian rest-activity rhythm was assessed by means of actigraphy before and after the training period and again 1 year after discontinuation. As a control for possible seasonal effects, repeated actigraphic recordings were performed during the same times of the year as were the pre and post measurements in a control group of 8 healthy elderly males. Fitness training induced a significant reduction in the fragmentation of the rest-activity rhythm. Moreover, the fragmentation of the rhythm was negatively correlated with the level of fitness achieved after the training. No seasonal effect was found. Previous findings in human and animal studies are reviewed, and several possible mechanisms involved in the effect of fitness training on circadian rhythms are discussed. The results suggest that fitness training may be helpful in elderly people suffering from sleep problems related to circadian rhythm disturbances.

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Single injections of triazolam, a short-acting benzodiazepine, lengthen the period of the circadian activity rhythm in golden hamsters

Cited by 33 publications

References 18 publications

Circadian phase shifting induced by clonidine injections in Syrian hamsters

Circadian phase shifting induced by clonidine injections in Syrian hamsters

Scheduled Voluntary Wheel Running Activity Modulates Free-Running Circadian Body Temperature Rhythms in Octodon degus

Long-Term Fitness Training Improves the Circadian Rest-Activity Rhythm in Healthy Elderly Males

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