Effects of T cycles of light/darkness and periodic forced activity on methamphetamine-induced rhythms in intact and SCN-lesioned rats: Explanation by an hourglass-clock model

Ruis, J.F.; Buys, J; Cambras, Trinitat; Rietveld, W.J.

doi:10.1016/0031-9384(90)90020-5

Cited by 22 publications

(18 citation statements)

References 23 publications

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“…Similar rhythms can also be induced in SCNX rats when MAP is administered via osmotic pumps instead of drinking water (Honma, Honma et al 1987). In SCNX rats, chronic MAP also induces circadian rhythms of body temperature, drinking, feeding, total activity and corticosterone (Morimasa, Wirz-Justice et al 1987;Rietveld, Korving et al 1987;Honma, Honma et al 1988;Ruis, Buys et al 1990;Hiroshige, Honma et al 1991). These rhythms seem to preserve their normal phase relationships with the locomotor activity rhythm during the MAP treatment.…”

Section: Effects Of Map On Circadian Behavior (And Other) Rhythmsmentioning

confidence: 88%

“…In fact, it is still debated whether MASCO is a bona fide circadian oscillator rather than a simple hourglass mechanism (Ruis, Buys et al 1990). The experiments presented in this thesis aim to fill some of these gaps in our understanding of this fascinating major oscillator.…”

Section: Circadian System In Mammalsmentioning

confidence: 99%

“…Chronic MAP produces rhythmicity in arrhythmic Clock m1Jt mutant mice in constant darkness (DD) (Masubuchi, Honma et al 2001). Chronic MAP also induces circadian rhythms of body temperature, drinking, feeding, total activity and corticosterone (Morimasa, Wirz-Justice et al 1987;Rietveld, Korving et al 1987;Honma, Honma et al 1988;Ruis, Buys et al 1990;Hiroshige, Honma et al 1991). These data demonstrate that the MASCO is anatomically distinct from the SCN.…”

Section: Introductionmentioning

confidence: 99%

“…These data demonstrate that the MASCO is anatomically distinct from the SCN. It has been proposed that an hourglass mechanism rather than a circadian oscillator may explain MAP-induced rhythmic activity (Ruis, Buys et al 1990). …”

Section: Introductionmentioning

confidence: 99%

“…Alternatively, it is possible to explain these results (with the important exception of rhythmicity produced in SCNX animals treated with MAP in osmotic pumps) by an hourglass mechanism that is driven by rhythmic drinking (Ruis, Buys et al 1990). Because MAP is known to cause hyperactivity and increase the duration of wakefulness (alpha), this spontaneous increase in alpha, followed by increased rebound sleep may seem like a lengthened rhythm.…”

Section: Effects Of Map On Circadian Behavior (And Other) Rhythmsmentioning

confidence: 99%

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Effects of Methamphetamine on Circadian Rhythms of Mice

Tataroglu

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The circadian system allows an organism to anticipate rhythmic changes in the external conditions and thereby increases its fitness. In rodents, the circadian clock resides in a pair of nuclei called the suprachiasmatic nuclei (SCN) which regulates rhythms of locomotor behavior, body temperature and some other physiological variables. However, this hierarchical organization of the circadian system is challenged by the discovery of two SCN-independent major oscillators; a feeding-entrainable oscillator (FEO) and a methamphetamine-sensitive circadian oscillator (MASCO). The presence of SCN, FEO and MASCO suggests a central multi-oscillatory organization of the circadian system in rodents, similar to the organization found in non-mammal vertebrates. At present, we know very little about how this complex multi-oscillator system is integrated.Although there is substantial information available about the SCN, the molecular components, localization and natural role of MASCO in the body are unknown. In fact, it is still debated whether MASCO is a bona fide circadian oscillator rather than a simple hourglass mechanism. This is largely due to the lack of a robust circadian model to study the effects of methamphetamine (MAP) on circadian rhythms. This thesis aims to fill some of these gaps in our understanding of this fascinating major oscillator 3 Using mice, we successfully replicated the published effects of chronic MAP on the circadian rhythms of rats. In fact, the differences such as more robust and clear activity rhythms, more pronounced MAP-induced second components of the rhythm and obvious sex and strain differences make the mice a better model.The results also indicated that MASCO interacts with the SCN in a manner that is strain, sex and dose dependent. Our experiments testing the hourglass explanation showed that the effects of MAP can not be explained by such a mechanism. This suggests that MASCO has circadian properties and is indeed a bona fide circadian clock. We also tried to elucidate the similarities between the molecular components of SCN and MASCO using several circadian mutant mice that were available to us. Although, the results of these experiments are not adequate to propose a list of known circadian genes that are involved in MASCO function, they provide the background for future studies that will determine the differences between the molecular components of SCN and MASCO.Utilization of the mouse strains presented in this thesis will provide an easy to obtain standard model where MASCO can be studied using latest developments in genetics and molecular biology. Identification of the natural role of MASCO in the body and its interactions with other oscillators in the body is of both scientific and clinical significance and will greatly improve our understanding of the circadian system in mammals.4 Acknowledgements I would like to thank Dr.Menaker for his continuous support and outstanding mentoring. I owe whatever I accomplished during my time at UVA to him and could never repay my debt. I a...

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Section: Effects Of Map On Circadian Behavior (And Other) Rhythmsmentioning

confidence: 88%

Section: Circadian System In Mammalsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Effects Of Map On Circadian Behavior (And Other) Rhythmsmentioning

confidence: 99%

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Effects of Methamphetamine on Circadian Rhythms of Mice

Tataroglu

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Effects of circadian disruption on methamphetamine consumption in methamphetamine-exposed rats

et al. 2014

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Rationale A substantial number of clinical studies indicate associations between sleep abnormalities and drug abuse; however, the role played by the circadian system in the development of addiction is largely unknown. Objective The aim of this study was to examine the effects of experimentally induced chronic jet lag on methamphetamine consumption in a rat model of methamphetamine drinking. Methods Male Sprague-Dawley rats (n=32) were housed in running wheel cages in a 12:12 light:dark cycle. One group of rats (n=16) was given two weeks of forced methamphetamine consumption (0.01% in drinking water; meth pre-exposed) while a second group (n=16, not pre-exposed) received water only. This was followed by a two week abstinence period during which half of the animals from each group were exposed to 4 consecutive 6-hr advancing phase shifts of the light:dark cycle, while the other half remained on the original light:dark cycle. Methamphetamine consumption was assessed in all rats following the deprivation period using a two-bottle choice paradigm. Results Methamphetamine consumption was initially lower in methamphetamine pre-exposed vs. not pre-exposed rats. However, during the second week following abstinence, consumption was significantly higher in phase shifted rats of the methamphetamine pre-exposed group compared to all other groups. Conclusions These data reveal an effect of circadian rhythm disturbance on methamphetamine consumption, and suggest that dysregulation of the circadian system be considered in the etiology of relapse and addiction.

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Phase-dependent phase shift of methamphetamine-induced circadian rhythm by haloperidol in SCN-lesioned rats

Honma

1995

Brain Research

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Effects of T cycles of light/darkness and periodic forced activity on methamphetamine-induced rhythms in intact and SCN-lesioned rats: Explanation by an hourglass-clock model

Cited by 22 publications

References 23 publications

Effects of Methamphetamine on Circadian Rhythms of Mice

Effects of Methamphetamine on Circadian Rhythms of Mice

Effects of circadian disruption on methamphetamine consumption in methamphetamine-exposed rats

Phase-dependent phase shift of methamphetamine-induced circadian rhythm by haloperidol in SCN-lesioned rats

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