The circadian system plays an immense role in controlling physiological processes in our body.The suprachiasmatic nucleus (SCN) supervises this system,regulating and harmonising the circadian rhythms in our body.Most ...The circadian system plays an immense role in controlling physiological processes in our body.The suprachiasmatic nucleus (SCN) supervises this system,regulating and harmonising the circadian rhythms in our body.Most neurons present in the SCN are GABAergic neurons.Although GABA is considered the main inhibitory neurotransmitter of the CNS,recent studies have shown that excitatory responses were recorded in this area.These responses are enabled by an increase in intracellular chloride ions[Cl;];levels.The chloride (Cl;) levels in GABAergic neurons are controlled by two solute carrier 12 (SLC12)cation-chloride-cotransporters (CCCs):Na^(+)/K^(+)/Cl^(-)co-transporter (NKCC1) and K^(+)/Cl^(-)cotransporter (KCC2),that respectively cause an influx and efflux of Cl^(-).Recent works have found altered expression and/or activity of either of these co-transporters in SCN neurons and have been associated with circadian rhythms.In this review,we summarize and discuss the role of CCCs in circadian rhythms,and highlight these recent advances which attest to CCC’s growing potential as strong research and therapeutic targets.展开更多
Many organisms have evolved an approximately 24-hour circadian rhythm that allows them to achieve internal physiological homeostasis with external environment.Suprachiasmatic nucleus（SCN） is the central pacemaker of...Many organisms have evolved an approximately 24-hour circadian rhythm that allows them to achieve internal physiological homeostasis with external environment.Suprachiasmatic nucleus（SCN） is the central pacemaker of circadian rhythm,and its activity is entrained to the external light-dark cycle.The SCN controls circadian rhythm through regulating the synthesis of melatonin by pineal gland via a multisynaptic pathway.Light,especially shortwavelength blue light,is the most potent environmental time cue in circadian photoentrainment.Recently,the discovery of a novel type of retinal photoreceptors,intrinsically photosensitive retinal ganglion cells,sheds light on the mechanism of circadian photoentrainment and raises concerns about the effect of ocular diseases on circadian system.With age,light transmittance is significantly decreased due to the aging of crystalline lens,thus possibly resulting in progressive loss of circadian photoreception.In the current review,we summarize the circadian physiology,highlight the important role of light in circadian rhythm regulation,discuss about the correlation between age-related cataract and sleep disorders,and compare the effect of blue light-filtering intraocular lenses（lOLs） and ultraviolet only filtering lOLs on circadian rhythm.展开更多
Objective: The objective is to observe the treatment effect of electro-acupuncture (EA) on core circadian clock gene Per2 and Bmal1 expression in hypothalamus of sleep-deprivation (SD) rats. Methods: Thirty-two Wistar...Objective: The objective is to observe the treatment effect of electro-acupuncture (EA) on core circadian clock gene Per2 and Bmal1 expression in hypothalamus of sleep-deprivation (SD) rats. Methods: Thirty-two Wistar male rats were randomly divided into 4 groups. Mice in the blank control group did not receive any treatment;the remaining groups were applied with para-chlorophenylalanine (PCPA) 300 mg/kg intraperitoneal injection for 2 days. Diazepam group received intraperitoneal injection of Diazepam (0.9 mg/kg, i.p.) one time a day for 5 days, while M group was treated with saline (0.9 mg/kg, i.p.) at the same time. Rats in EA group were given EA treatment, 20 minutes, once a day for 5 days, and rats in remaining groups were put into fixation-machine for the same time everyday, lasting for 5 days. Rats were sacrificed after anesthesia at the 8th day. Real-time PCR was adopted to detect the expression in clock gene Per2 and Bmal1 of each group. Results: Compared with blank control group, the expression of Per2 was significant decreased in PCPA model group (P 0.05). Conclusion: EA can significant up-regulate the expression of Per2 in SD rats, and down-regulate gene Bmal1 expression, and benefiting the weight of rats. Thus, EA is a potentially promising intervention to treat sleep-deprivation.展开更多
The central circadian clock in the brain controls the time-of-the-day variations in acute meal responses,with a low glycemic response but a high satiety/thermo-genic response to meals consumed at waking compared to ot...The central circadian clock in the brain controls the time-of-the-day variations in acute meal responses,with a low glycemic response but a high satiety/thermo-genic response to meals consumed at waking compared to other time points.Consistently,studies show that consuming a significant proportion of calories,particularly carbohydrates,in breakfast is beneficial for the chronic management of obesity and its associated metabolic syndrome,compared to consuming identical meals at dinner.Conversely,breakfast skipping or/and late dinner can have unfavorable metabolic outcomes.It remains controversial how meal frequency affects metabolic health.In contrast,irregular meals,especially irregular breakfasts,show consistent adverse metabolic consequences.Time-restricted feeding(TRF),with all calories consumed within less than 12-h per day,can improve metabolism and extend lifespan.A major component of TRF in humans is caloric restriction,which contributes significantly to the beneficial effects of TRF in humans.By comparison,TRF effects in rodents can be independent of caloric restriction and show day/night phase specificity.TRF could alleviate metabolic abnormalities due to circadian disruption,but its effects appear independent of the circadian clock in rodents.Understanding neuroendocrine mechanisms underlying clock-mediated metabolic regulation will shed light on the metabolic effects of temporal meal patterns.展开更多
A new mammalian photoreceptor was recently discovered to reside in the ganglion cell layer of the inner retina.These intrinsically photosensitive retinal ganglion cells(ipRGCs) express a photopigment,melanopsin,that c...A new mammalian photoreceptor was recently discovered to reside in the ganglion cell layer of the inner retina.These intrinsically photosensitive retinal ganglion cells(ipRGCs) express a photopigment,melanopsin,that confers upon them the ability to respond to light in the absence of all rod and cone photoreceptor input.Although relatively few in number,ipRGCs extend their dendrites across large expanses of the retina making them ideally suited to function as irradiance detectors to assess changes in ambient light levels.Phototransduction in ipRGCs appears to be mediated by transient receptor potential channels more closely resembling the phototransduction cascade of invertebrate rather than vertebrate photoreceptors.ipRGCs convey irradiance information centrally via the optic nerve to influence several functions.ipRGCs are the primary retinal input to the hypothalamic suprachiasmatic nucleus(SCN),a circadian oscillator and biological clock,and this input entrains the SCN to the day/night cycle.ipRGCs contribute irradiance signals that regulate pupil size and they also provide signals that interface with the autonomic nervous system to regulate rhythmic gene activity in major organs of the body.ipRGCs also provide excitatory drive to dopaminergic amacrine cells in the retina,providing a novel basis for the restructuring of retinal circuits by light.Here we review the ground-breaking discoveries,current progress and directions for future investigation.展开更多
基金supported by a Commonwealth Ph D Scholarship(S.S.J.)NSFC grants to Y.W.(31771188,31471027)+1 种基金the University of Exeter Medical School start-up fund(J.Z.)NIH Grants R01 NS109358(J.Z.)。
文摘The circadian system plays an immense role in controlling physiological processes in our body.The suprachiasmatic nucleus (SCN) supervises this system,regulating and harmonising the circadian rhythms in our body.Most neurons present in the SCN are GABAergic neurons.Although GABA is considered the main inhibitory neurotransmitter of the CNS,recent studies have shown that excitatory responses were recorded in this area.These responses are enabled by an increase in intracellular chloride ions[Cl;];levels.The chloride (Cl;) levels in GABAergic neurons are controlled by two solute carrier 12 (SLC12)cation-chloride-cotransporters (CCCs):Na^(+)/K^(+)/Cl^(-)co-transporter (NKCC1) and K^(+)/Cl^(-)cotransporter (KCC2),that respectively cause an influx and efflux of Cl^(-).Recent works have found altered expression and/or activity of either of these co-transporters in SCN neurons and have been associated with circadian rhythms.In this review,we summarize and discuss the role of CCCs in circadian rhythms,and highlight these recent advances which attest to CCC’s growing potential as strong research and therapeutic targets.
文摘Many organisms have evolved an approximately 24-hour circadian rhythm that allows them to achieve internal physiological homeostasis with external environment.Suprachiasmatic nucleus（SCN） is the central pacemaker of circadian rhythm,and its activity is entrained to the external light-dark cycle.The SCN controls circadian rhythm through regulating the synthesis of melatonin by pineal gland via a multisynaptic pathway.Light,especially shortwavelength blue light,is the most potent environmental time cue in circadian photoentrainment.Recently,the discovery of a novel type of retinal photoreceptors,intrinsically photosensitive retinal ganglion cells,sheds light on the mechanism of circadian photoentrainment and raises concerns about the effect of ocular diseases on circadian system.With age,light transmittance is significantly decreased due to the aging of crystalline lens,thus possibly resulting in progressive loss of circadian photoreception.In the current review,we summarize the circadian physiology,highlight the important role of light in circadian rhythm regulation,discuss about the correlation between age-related cataract and sleep disorders,and compare the effect of blue light-filtering intraocular lenses（lOLs） and ultraviolet only filtering lOLs on circadian rhythm.
文摘Objective: The objective is to observe the treatment effect of electro-acupuncture (EA) on core circadian clock gene Per2 and Bmal1 expression in hypothalamus of sleep-deprivation (SD) rats. Methods: Thirty-two Wistar male rats were randomly divided into 4 groups. Mice in the blank control group did not receive any treatment;the remaining groups were applied with para-chlorophenylalanine (PCPA) 300 mg/kg intraperitoneal injection for 2 days. Diazepam group received intraperitoneal injection of Diazepam (0.9 mg/kg, i.p.) one time a day for 5 days, while M group was treated with saline (0.9 mg/kg, i.p.) at the same time. Rats in EA group were given EA treatment, 20 minutes, once a day for 5 days, and rats in remaining groups were put into fixation-machine for the same time everyday, lasting for 5 days. Rats were sacrificed after anesthesia at the 8th day. Real-time PCR was adopted to detect the expression in clock gene Per2 and Bmal1 of each group. Results: Compared with blank control group, the expression of Per2 was significant decreased in PCPA model group (P 0.05). Conclusion: EA can significant up-regulate the expression of Per2 in SD rats, and down-regulate gene Bmal1 expression, and benefiting the weight of rats. Thus, EA is a potentially promising intervention to treat sleep-deprivation.
基金supported by NIH(DK111436,HL153320,AG069966,and ES027544)the John S.Dunn Foundation,the Mrs.Clifford Elder White Graham Endowed Research Fund,theDan L Duncan Comprehensive Cancer Center(P30CA125123)+2 种基金the Texas Medical Center Digestive Diseases Center(P30DK056338)the SPORE program in lymphoma at Baylor College of Medicine(P50 CA126752)the Gulf Coast Center for Precision Environmental Health(P30ES030285).
文摘The central circadian clock in the brain controls the time-of-the-day variations in acute meal responses,with a low glycemic response but a high satiety/thermo-genic response to meals consumed at waking compared to other time points.Consistently,studies show that consuming a significant proportion of calories,particularly carbohydrates,in breakfast is beneficial for the chronic management of obesity and its associated metabolic syndrome,compared to consuming identical meals at dinner.Conversely,breakfast skipping or/and late dinner can have unfavorable metabolic outcomes.It remains controversial how meal frequency affects metabolic health.In contrast,irregular meals,especially irregular breakfasts,show consistent adverse metabolic consequences.Time-restricted feeding(TRF),with all calories consumed within less than 12-h per day,can improve metabolism and extend lifespan.A major component of TRF in humans is caloric restriction,which contributes significantly to the beneficial effects of TRF in humans.By comparison,TRF effects in rodents can be independent of caloric restriction and show day/night phase specificity.TRF could alleviate metabolic abnormalities due to circadian disruption,but its effects appear independent of the circadian clock in rodents.Understanding neuroendocrine mechanisms underlying clock-mediated metabolic regulation will shed light on the metabolic effects of temporal meal patterns.
基金supported by grants from the National Institutes of Health, the National Institute of Neurological Disorders and Stroke R01 NS035615the National Eye Institute R01 EY017809
文摘A new mammalian photoreceptor was recently discovered to reside in the ganglion cell layer of the inner retina.These intrinsically photosensitive retinal ganglion cells(ipRGCs) express a photopigment,melanopsin,that confers upon them the ability to respond to light in the absence of all rod and cone photoreceptor input.Although relatively few in number,ipRGCs extend their dendrites across large expanses of the retina making them ideally suited to function as irradiance detectors to assess changes in ambient light levels.Phototransduction in ipRGCs appears to be mediated by transient receptor potential channels more closely resembling the phototransduction cascade of invertebrate rather than vertebrate photoreceptors.ipRGCs convey irradiance information centrally via the optic nerve to influence several functions.ipRGCs are the primary retinal input to the hypothalamic suprachiasmatic nucleus(SCN),a circadian oscillator and biological clock,and this input entrains the SCN to the day/night cycle.ipRGCs contribute irradiance signals that regulate pupil size and they also provide signals that interface with the autonomic nervous system to regulate rhythmic gene activity in major organs of the body.ipRGCs also provide excitatory drive to dopaminergic amacrine cells in the retina,providing a novel basis for the restructuring of retinal circuits by light.Here we review the ground-breaking discoveries,current progress and directions for future investigation.
