Temporal Variation in the Interaction Between Calcium Channel Blockers and Morphine-Induced Analgesia

Circadian variations in the interaction between calcium channel blockers and morphine-induced analgesia were determined by the mouse hot-plate test. Calcium channel blockers diltiazem, verapamil, or nicardipine alone did not display any significant analgesic effect, but all of them potentiated morphine-induced analgesia when injected 30 min prior to morphine at most of the injection times. In terms of percent absolute potentiation, they produced more potentiation during the light period than darkness. Their potentiating effects decreased abruptly during darkness, and around the midtime of the dark period no significant potentiation of morphine-induced analgesia was observed. It is concluded that these fluctuations in the magnitude of interaction between calcium channel blockers and morphine must be taken into consideration particularly in studies dealing with the role of calcium in analgesia.     

昼夜节律的改变对视网膜感光视蛋白melanopsin表达的影响

目的 研究昼夜节律的改变对视网膜感光视蛋白melanopsin表达的影响.方法 出生14 d (P14)C57BL/6J小鼠随机分为实验组和正常对照组,实验组每天给予24 h持续光照,对照组模拟正常昼夜节律每天给予12 h光照、12 h黑暗环境,运用免疫荧光染色结合RT-PCR技术,分别检测实验组和对照组小鼠在光照1周后和8周后视网膜感光视蛋白melanopsin的表达情况.结果 免疫荧光染色结果显示感光视蛋白melanopsin主要位于视网膜神经节细胞层,少部分位于内核层.小鼠光照1周后melanopsin阳性细胞的表达数目实验组少于对照组;RT-PCR结果示小鼠光照1周和8周时melanopsin的mRNA含量实验组均少于各自的对照组,两者具有统计学意义(P＜0.01).结论 持续光照可以减少视网膜感光视蛋白melanopsin的表达,提示melanopsin阳性神经节细胞为光敏感性细胞,其表达可能对维持正常的昼夜节律有重要作用.     

Mitotic activity and cell degeneration in the mouse thymus over a period of 24 hrs

Summary The mitotic and pyknotic indices were calculated over a period of 24 hrs in four different zones of the mouse thymus (Balb/C). Counts were based on 1 micron sections of Epon-embedded tissue. This technique gives a more accurate mitotic index than has been calculated in the past because mitotic figures in the prophase stage are more easily recognizable. Mitotic as well as pyknotic index showed a distinct diurnal rhythm in the subcapsular zone, the rhythm being less distinct towards the medulla, where no significant diurnal fluctuations were demonstrated. It was shown that the index variations could be correlated to significant variations in the mitotic time.     

Circadian variation of nitric oxide synthase activity in mouse tissue

Endogenous nitric oxide (NO) is an important mediator in the processes that control biological clocks and circadian rhythms. The present study was designed to elucidate if NO synthase (NOS) activity in the brain, kidney, testis, aorta, and lungs and plasma NO_x levels in mice are controlled by an endogenous circadian pacemaker. Male BALB/c mice were exposed to two different lighting regimens of either light-dark 14:10 (LD) or continuous lighting (LL). At nine different equidistant time points (commencing at 09:00h) blood samples and tissues were taken from mice. The plasma and tissue homogenates were used to measure the levels of NO₂+ NO₃^- (NO_x) and total protein. The NO_x concentrations were determined by a commercial nitric oxide synthase assay kit, and protein content was assessed in each homogenate tissue sample by the Lowry method. Nitric oxide synthase activity was calculated as pmol/mg protein/h. The resulting patterns were analyzed by the single cosinor method for pre-adjusted periods and by curve-fitting programs to elucidate compound rhythmicity. The NOS activity in kidneys of mice exposed to LD exhibited a circadian rhythm, but no rhythmicity was detected in mice exposed to LL. Aortic NOS activity displayed 24h rhythmicity only in LL. Brain, testis, and lung NOS activity and plasma NO_x levels displayed 24h rhythms both in LD and LL. Acrophase values of NOS activity in brain, kidney, testis, and lungs were at midnight corresponding to their behavioral activities. Compound rhythms were also detected in many of the examined patterns. The findings suggest that NOS activity in mouse brain, aorta, lung, and testis are regulated by an endogenous clock, while in kidney the rhythm in NOS activity is synchronized by the exogenous signals.     

Effects of Depressed Affect on Diurnal and Ultradian Variations in Mood in a Healthy Sample

The study investigated diurnal and ultradian variations in cheerful and depressed mood in a healthy sample, and examined whether these variations were related to severity of depressed affect. Thirty employed volunteers used a pocket computer to complete self-rating scales of depression and cheerfulness every 2 h for 14 days except during sleep periods. They also completed the Beck Depression Inventory (BDI) and the General Health Questionnaire (GHQ). Analysis of variance of depressed mood showed a significant interaction between time of day and BDI/GHQ, in which only the mood of the high BDI/GHQ groups got worse during the day. The low BDI group showed a diurnal variation in cheerful mood in which mood was at its best in the early evening. Cosinor and “binfit” analysis of raw and residual time-series showed that more than half of the participants had significant fitting ultradian rhythms in mood in the range 3-9 h. However, only the number of significant fits for residual cheerful mood was substantially above the level of chance. The amplitudes of the ultradian rhythms in raw depressed mood were greater in participants scoring higher on the BDI/GHQ scales, but this seemed to reflect an increase in serial dependency between depressed mood states. The results are discussed in relation to circadian rhythms in mood and depression.     

Different patterns of circadian oscillation in the suprachiasmatic nucleus of hamster,mouse, and rat

Although spontaneous neural firing in the mammalian suprachiasmatic nucleus is accepted to peak once during mid-subjective day, dual activity peaks have been reported in horizontal brain slices taken from hamsters. These two peaks were interpreted as new evidence for the theory of dual circadian oscillators and raised the expectation that such activity would be found in other circadian model systems. We examined hamster, mouse, and rat slices in both coronal and horizontal planes and found a second peak of activity only in hamster horizontal preparations. This raises interesting questions about the relative circadian physiology of these important experimental animals.Abbreviations CT circadian time - SCN suprachiasmatic nucleus P.W. Burgoon and P.T. Lindberg contributed equally to this work.     

Gene-Dependent Effect of Lithium on Circadian Rhythms in Mice (Mus Musculus)

Lithium has been shown to lengthen free-running circadian periods in a variety of species. Here we show that lithium carbonate differentially lengthens the free-running period of a circadian wheel running rhythm in BALB/CByJ and C57BL/10Sn inbred mouse strains. This result supports previous evidence that lithium lengthens mammalian circadian rhythms, and also demonstrates that gene differences can mediate individual differences in response to lithium treatment.     

Ecological Aspects of Circadian Rhythms in Six Species of Omni-Seasonal Beetles (Coleoptera, Tenebrionidae) Inhabiting Kara Kum Desert (Turkmenistan)

Circadian rhythms of activity were compared in ground-dwelling Tenebrionid beetles from the Kara Kum sand desert: Trigonoscelis gigas Reitter, Trigonoscelis sublaevicollis Reitter, Pisterotarsa gigantea Fish.-W., Sternodes caspicus Pall, Blaps faustii Seidlitz, and Ocnera imbricata Fish.-W. For the observations, artificial pens (enclosures) 60 × 60 cm and 80 cm deep were arranged in field conditions and filled with various kinds of sand to simulate natural habitats as closely as possible. The activity of individually marked beetles was assessed visually and recorded every 30 min. The beetle species studied had different types of behavior, from strictly crepuscular to strictly nocturnal. Closely related species sharing one habitat differed in activity pattern — they occupied different time niches; hence their circadian rhythms contribute to reproductive isolation. In contrast, non-closely related species could have similar circadian patterns as a result of convergent evolution. In experiments with T. gigas, we failed to stimulate individual variability among beetles in circadian pattern by applying additional light and heat at night. Therefore, the circadian rhythms in field conditions were found to be remarkably stable, which can be explained by our model of the beetle circadian system consisting of two strongly coupled oscillators. However, in laboratory conditions, we previously observed a wide range of individual variability in free-running circadian rhythms. The strong coupling between two putative endogenous circadian oscillators is a crucial tool for beetles to survive in a harsh arid environment. Such organization of the circadian system ensures synchronous activity of beetles despite individual differences, thus preserving the variability of circadian clock properties in a population, which increases chances for survival of a population in a changing environment.     

Effects of dark-light step transitions on circadian locomotor activity rhythms of the hagfish,Eptatretus burgeri

Captive hagfish,Eptatretus burgeri, were subjected to step transitions from continuous dark (DD) to continuous light (LL) and their locomotor activity patterns recorded. Free-running activity rhythms occurred in both the DD and LL regimes. The timing of the transition influenced the circadian period (τ), the relationship between the period response (δτ, or τ{inLL}–τ{inDD}, change in the circadian period) and the former being represented by a cosine curve δτ became most positive and most negative when hagfish underwent a DD-LL transition shortly before the beginning of the duration of activity (α) and shortly after the end of such, respectively. The phase response (δ-phase, change in the relative timing of the activity phase) was characterized by a delay in the activity phase after the DD-LL transition, although its magnitude bore no relation to the timing of the transition.     

Epigenetic Maternal Effects on Endogenous Rhythms in Precocial Birds

Development involves interactions between genetic and environmental influences. Vertebrate mothers are generally the first individuals to encounter and interact with young animals. Thus, their role is primordial during ontogeny. The present study evaluated non‐genomic effects of mothers on the development of rhythms of precocial Japanese quail (Coturnix c. japonica). First, we investigated the influence of mothering on the ontogeny of endogenous rhythms of young. We compared circadian and ultradian rhythms of feeding activity of quail reared with or without adoptive mothers. More brooded than non‐brooded quail presented a circadian and/or an ultradian rhythm. Thus, the presence of the mother during the normal brooding period favors, in the long term, expression of rhythms in the young. Second, we investigated the influence of rhythmic phenotype of the mother on the development of endogenous rhythms of young by comparing quail brooded by circadian‐rhythmic adoptive mothers (R) to quail brooded by circadian‐arrhythmic adoptive mothers (A). More R‐brooded than A‐brooded quail expressed circadian rhythmicity, and circadian rhythm clarities were greater in R‐brooded than A‐brooded quail. Ultradian rhythmicity did not differ between R‐ and A‐brooded quail, nor between R and A adoptive mothers. Thus, the rhythmic phenotypes of quail mothers influence the rhythmic phenotypes of their young. Our results demonstrate that mothers of precocial birds influence epigenetically the ontogeny of endogenous rhythms of the young they raise.     

The Circadian Clock Machinery During Early Development of Senegalese sole (Solea senegalensis): Effects of Constant Light and Dark Conditions

Circadian rhythms are established very early during vertebrate development. In fish, environmental cues can influence the initiation and synchronization of different rhythmic processes. Previous studies in zebrafish and rainbow trout have shown that circadian oscillation of clock genes represents one of the earliest detectable rhythms in the developing embryo, suggesting their significance in regulating the coordination of developmental processes. In this study, we analyzed the daily expression of the core clock components Per1, Per2, Per3, and Clock during the first several days of Senegalese sole development (0–4 d post fertilization or dpf) under different lighting regimes, with the aim of addressing when the molecular clock first emerges in this species and how it is affected by different photoperiods. Rhythmic expression of the above genes was detected from 0 to 1 dpf, being markedly affected in the next few days by both constant light (LL) and dark (DD) conditions. A gradual entrainment of the clock machinery was observed only under light-dark (LD) cycles, and robust rhythms with increased amplitudes were established by 4 dpf for all clock genes currently studied. Our results show the existence of an embryonic molecular clock from the 1st d of development in Senegalese sole and emphasize the significance of cycling LD conditions when raising embryos and early larvae. (Author correspondence: munoz.cueto@uca.es; carlos.pendon@uca.es)     

Effects of optic lobe ablation on circadian activity in the mosquito, Culex pipiens pallens

ABSTRACT. Surgical manipulation was used to show that in the mosquito, Culex pipiens pallens , the circadian pacemaker is probably not located in the optic lobes. Mosquitoes deprived of the greater part of their optic lobes still maintained a circadian activity rhythm: in DD with τ= c . 20–23 h, in LL with τ= c . 14–15 h. The operated mosquitoes showed diphasic activity which entrained to LD 16:8 h (at 200 lux), implying the existence of an extraocular photoreceptive pathway.     

The Circadian Energy Scale (CIRENS): Two Simple Questions for a Reliable Chronotype Measurement Based on Energy

This study presents the Circadian Energy Scale (CIRENS), a very short and simple chronotype measurement tool based on energy. The CIRENS consists of two introspective questions about the usual energy level (very low, low, moderate, high, or very high, scored 1 to 5) in the morning and in the evening. The difference between energy level scores (?4 to 4) felt by respondents in the evening and morning defines the chronotype score and classification. A concurrent validity analysis of the CIRENS with the widely used Horne and Östberg Morningness-Eveningness Questionnaire (MEQ) was conducted using a sample of 225 college students, and with MSFsc, a sleep-based chronotype assessment tool based on the Munich Chronotype Questionnaire (MCTQ), using a sample of 34,530 subjects (18–83 yrs, 27% males). This large sample was collected in a Web survey for behavioral correlates of the CIRENS with variables previously associated with chronotype differences. The correlation of the CIRENS chronotype score was r?=??.70 with the MEQ and r?=?.32 with the MSFsc. CIRENS chronotype scores declined with age and were not affected by sex. Both CIRENS and MSFsc chronotype scores were related to differences in tobacco, caffeine, and cola soft-drink consumption (all higher in evening types). The CIRENS provides a simple chronotype index and a measure of absolute energy throughout the day and seems to be a reliable chronotype assessment tool that may be useful both clinically and for large-scale studies. (Author correspondence: diogorlara@gmail.com)     

Diurnal rhythm of emergence from pupae in parasitic wasp Trichogramma evanescens Westw. (Insecta: Hymenoptera)

Abstract

Pupal eclosion of Trichogramma evanescens Westw. was studied in different conditions of light‐darkness and temperature fluctuations. The results revealed that under natural light cycles Trichogramma exhibits a distinct rhythm of emergence from pupae. Maximum emergence takes place in the morning. This rhythm persists in constant dim red light and temperature, so it is endogenous in nature. The rhythm can be entrained by artificial 24‐h temperature cycles or by day‐night cycles of light with a very low intensity of illumination (<0.01 lux). Nevertheless a single pulse of bright light or of high temperature is not able to reset the rhythm. The emergence rhythm was also absent if the culture was grown in constant darkness and temperature.     

Temporal Variation in Drug Interaction Between Lithium and Morphine‐Induced Analgesia

The administration‐time‐dependent aspects of the drug interaction between lithium and morphine‐induced analgesia were studied using the mouse hot‐plate test at six different times of day, each scheduled at 4 h intervals. Lithium treatment alone, in doses of 1 to 10 mmol/kg administered intraperitoneally (i.p.) did not significantly alter test latencies compared to the corresponding clock‐time in saline‐injected controls. Basal pain sensitivity and morphine‐induced antinociceptive activity displayed significant circadian rhythms as assessed by the hot‐plate response latencies, with higher values occurring during the nocturnal activity than during the daytime rest span. Acute administration of lithium, in a dose of 3 mmol/kg, 30 min prior to morphine dosing did not influence morphine‐induced analgesia compared to all the clock‐time test‐matched morphine groups, except the 9 HALO (Hours After Lights On) one. There was a prominent potentiation of the morphine‐induced antinociception at this biological time during combined drug treatment. The latter finding demonstrates that administration‐time‐dependent differences in drug‐drug interactions need to be considered in both experimental designs and clinical settings.     

新克痛宁术后镇痛效果观察

目的了解眼镜蛇毒制剂新克痛宁对术后镇痛效果。方法对７２例胫腓骨折病人,在连续硬膜外阻滞麻醉下行切开复位内固定术,术后随机分为４组（每组１８例）向硬膜外腔注药：Ａ组新克痛宁０．２５ＩＵ／ｋｇ;Ｂ组新克痛宁０．１２５ＩＵ／ｋｇ加０．５％利多卡因液１０ｍｌ;Ｃ组吗啡２ｍｇ;Ｄ组吗啡１ｍｇ加０．５％利多卡因液１０ｍｌ。结果镇痛持续时间Ａ、Ｂ组明显延长,Ａ与Ｂ组分别为（４１２±２８）ｍｉｎ,与Ｃ、Ｄ组比较差异显著（Ｐ＜０．０５）。注药后３０～１２０ｍｉｎ,患肢足背皮肤温度,Ａ、Ｂ组亦高于Ｃ、Ｄ组（Ｐ＜０．０５）,且无不良反应。结论新克痛宁术后镇痛效果比吗啡好。     

Entrainment to light of circadian activity rhythms in tench (Tinca tinca)

The present article analyzes locomotor activity rhythms in Tinca tinca. To that end, three different experiments were conducted on 24 animals (20 g body weight) kept in pairs in 60-liter aquaria fitted with infrared sensors connected to a computer to continuously record fish movements. The first experiment was designed to study the endogenous circadian clock under free-running conditions [ultradian 40:40 min LD pulses and constant dark (DD)] and after shifting the LD cycle. Our results demonstrate that tench has a strictly nocturnal activity pattern, an endogenous rhythm being evident in 45.8% of the fish analyzed. The second experiment was conducted to test the influence of different photoperiods (LD 6:18, 12:12, 18:6, and 22:2) on locomotor activity, the results showing that even under an extremely long photoperiod, tench activity is restricted to dark hours. The third experiment examined the effect of light intensity on locomotor activity rhythms. When fish were exposed to decreasing light intensities (from 300:0 lux to 30:0, 3:0, and 0.3:0 lux) while maintaining a constant photoperiod (LD 12:12), the highest percentage of locomotor activity was in all cases associated with the hours of complete darkness (0 lux). In short, our results clearly show that (a) tench is a species with a strictly nocturnal behavior, and (b) daily activity rhythms gradually entrain after shifting the LD cycle and persist under free-running conditions, pointing to their circadian nature. However, light strongly influences activity rhythms, since (c) the length of the active phase is directly controlled by the photophase, and (d) strictly nocturnal behavior persists even under very dim light conditions (0.3 lux). The above findings deepen our knowledge of tench behavior, which may help to optimize the aquacultural management of this species, for example, by adjusting feeding strategies to their nocturnal behavior.     

Cisplatin Effects on Rhythmic Functions of Mice: Strain and Tissue Dependence

The competence to preserve the optimal timing relationships between rhythmic variables enables adaptation of mammals to alternate environmental conditions. The capability to re-entrain depends on genetic factors and the nature of imposed time cues. In the present study, the authors examined in rodent models, following a cancer chronochemotherapy, cisplatin (CP), the rhythm patterns of locomotor activity and of a few biochemical variables (alkaline phosphatase and creatinine phosphokinase in kidney tissue and plasma, kidney urea nitrogen, and white blood cell count). Males of two inbred mice strains, BALB/c and c57Bl/6J, received 10 consecutive daily intraperitoneal (i.p.) injections of either saline or CP at zeitgeber time 22 (ZT22). CP administration altered the rhythms of each examined function in both strains. The type and extent of the changes varied among variables, tissues/plasma, and mouse strain. Yet, the effect of CP was not detected on all parameters, but only in ～60% of them. In addition, in the majority of the studied parameters, BALB/c and c57Bl/6J mice differed in their response to CP. The temporal parameters of period and peak time were more affected by CP than were the level ones of mesor (time series mean) and amplitude of variation. This observation may indicate the involvement of independent pathways of action upon each of the rhythm parameter sets. As a result, the rhythm phenotype of each function was modified and novel timing relationships were shaped. The results show that the circadian systems of BALB/c and c57Bl/6J mice failed to re-entrain after cessation of CP injections (tested on the first day following the 10 d course of CP administration), pointing to a direct effect of the medication on the tissues. The findings imply that optimal chemotherapeutic protocols should be tailored individually, according to the current temporal order rather than administered at a fixed predetermined circadian time. Further studies are necessary to determine which variables and rhythmic parameters could be useful to determine the optimal timing of chronochemotherapy. (Author correspondence: lpeleg@sheba.health.gov.il)     

The morphology of the horseshoe crab (Limulus polyphemus) visual system

Summary Efferent fibers to the compound eye of the horseshoe crab, Limulus polyphemus, not only innervate the various pigment cells, but also invade the eccentric cell dendrite and the retinula cells. This finding provides a structural basis for the coupling of circadian rhythm between the efferents and the receptor cells.This short communication is Publication No. 1130 of the Oregon Regional Primate Research Center. The research was supported by Grants RR-00163 and EY-00392 from the National Institutes of Health     

Effects of meal timing on tumor progression in mice

Meal timing can reset circadian clocks in peripheral tissues. We investigated the effects of such non-photic entrainment on tumor growth rate. Two experiments involved a total of 61 male B6D2F(1) mice synchronized with an alternation of 12 h of light (L) and 12 h of darkness (D) (LD12:12). Mice were randomly allocated to have access to food ad libitum, or restricted to 4 or 6 h during L or D. Rest-activity and body temperature, two circadian outputs, were monitored with an intra-peritoneal sensor. Glasgow osteosarcoma was inoculated into both flanks of each mouse ten days after meal timing onset. Before tumor inoculation, meal timing during D amplified the 24-h rhythms in rest-activity and body temperature with minimal phase alteration as compared to ad libitum feeding. Conversely, meal timing during L induced dominant 12-h or 8-h rhythmic components in activity, nearly doubled the 24-h amplitude of body temperature and shifted its acrophase (time of maximum) from approximately mid-D to approximately mid-L. Thirteen days after tumor inoculation, mean tumor weight (+/- SEM, mg) was 1503 +/- 150 in ad libitum mice, 1077 +/- 157 in mice fed during D and 577 +/- 139 in mice fed during L (ANOVA, p < 0.0001). Overall survival was prolonged in the mice fed during L (median, 17.5 days, d) as compared with those fed during D (14.5 d) or ad libitum (14 d) (Log Rank, p = 0.0035). The internal desynchronization produced by meal timing during L slowed down tumor progression, an effect possibly resulting from improved host-mediated tumor control and/or altered tumor circadian clocks.