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van Dorp R, Rolleri E, Deboer T. Sleep and the sleep electroencephalogram in C57BL/6 and C3H/HeN mice. J Sleep Res 2024; 33:e14062. [PMID: 37803888 DOI: 10.1111/jsr.14062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 09/08/2023] [Accepted: 09/20/2023] [Indexed: 10/08/2023]
Abstract
Different mouse strains used in biomedical research show different phenotypes associated with their genotypes. Two mouse strains commonly used in biomedical sleep research are C57Bl/6 and C3H/He, the strains differ in numerous aspects, including their ability to secrete melatonin as well as the expression of several sleep-related genes. However, sleep regulation has only limitedly been compared between C3H/HeN and C57Bl/6 mice. We therefore compared sleep-wake behaviour and EEG-measured spectral brain activity for C57bl/6 and C3H/HeN mice during a 12:12 h light: dark baseline and during and after a 6 h sleep deprivation. The C3H mice spent more time in NREM sleep around the light-dark transition and more time in REM sleep during the dark phase compared with C57bl/6 mice. The C3H mice also showed more EEG activity in the 4.5-7.5 Hz range during all stages and a stronger 24 h modulation of EEG power density in almost all EEG frequencies during NREM sleep. After the sleep deprivation, C3H mice showed a stronger recovery response, which was expressed in both a larger increase in EEG slow wave activity (SWA) and more time spent in NREM sleep. We show large differences regarding sleep architecture and EEG activity between C3H and C57bl/6 mice. These differences include the amount of waking during the late dark phase, the 24 h amplitude in EEG power density, and the amount of REM sleep during the dark phase. We conclude that differences between mouse strains should be considered when selecting a model strain to improve the generalisability of studies investigating biomedical parameters related to sleep and circadian rhythms.
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Affiliation(s)
- Rick van Dorp
- Laboratory for Neurophysiology, Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Elisa Rolleri
- Laboratory for Neurophysiology, Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Tom Deboer
- Laboratory for Neurophysiology, Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
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2
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Wang X, Dong YT, Hu XM, Zhang JZ, Shi NR, Zuo YQ, Wang X. The circadian regulation of extracellular ATP. Purinergic Signal 2023; 19:283-295. [PMID: 35939197 PMCID: PMC9984637 DOI: 10.1007/s11302-022-09881-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 06/24/2022] [Indexed: 11/25/2022] Open
Abstract
Extracellular ATP is a potent signaling molecule released from various cells throughout the body and is intimately involved in the pathophysiological functions of the nervous system and immune system by activating P2 purinergic receptors. Recent increasingly studies showed that extracellular ATP exhibits circadian oscillation with an approximately 24-h periodicity, which participates in regulatory pathways of central oscillator suprachiasmatic nucleus and peripheral oscillator bladder, respectively. Oscillators modulate the protein expression of ATP release channels and ectonucleotidase activity through clock genes; indeed, real-time alterations of ATP release and degradation determine outcomes of temporal character on extracellular ATP rhythm. The regulatory pathways on extracellular ATP rhythm are different in central and peripheral systems. In this review, we summarize the circadian rhythm of extracellular ATP and discuss several circadian regulatory pathways in different organs via ATP release and degradation, to provide a new understanding for purinergic signaling in the regulatory mechanism of circadian rhythm and a potential target to research the circadian regulation of extracellular ATP in other circadian oscillators.
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Affiliation(s)
- Xin Wang
- School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, 37 Shi-er Qiao Road, Chengdu, 610075 China
| | - Yu-Ting Dong
- School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, 37 Shi-er Qiao Road, Chengdu, 610075 China
| | - Xiu-Ming Hu
- School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, 37 Shi-er Qiao Road, Chengdu, 610075 China
| | - Ji-Zhou Zhang
- School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, 37 Shi-er Qiao Road, Chengdu, 610075 China
| | - Nan-Rui Shi
- School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, 37 Shi-er Qiao Road, Chengdu, 610075 China
| | - Yan-Qin Zuo
- School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, 37 Shi-er Qiao Road, Chengdu, 610075 China
| | - Xu Wang
- School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, 37 Shi-er Qiao Road, Chengdu, 610075 China
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3
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Pfeffer M, von Gall C, Wicht H, Korf HW. The Role of the Melatoninergic System in Circadian and Seasonal Rhythms—Insights From Different Mouse Strains. Front Physiol 2022; 13:883637. [PMID: 35492605 PMCID: PMC9039042 DOI: 10.3389/fphys.2022.883637] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 03/22/2022] [Indexed: 01/01/2023] Open
Abstract
The melatoninergic system comprises the neurohormone melatonin and its molecular targets. The major source of melatonin is the pineal organ where melatonin is rhythmically produced during darkness. In mammals, melatonin biosynthesis is controlled by the central circadian rhythm generator in the suprachiasmatic nucleus (SCN) and photoreceptors in the retina. Melatonin elicits its function principally through two specific receptors called MT1 and MT2. MT1 is highly expressed in the SCN and the hypophysial pars tuberalis (PT), an important interface for control of seasonal functions. The expression of the MT2 is more widespread. The role of the melatoninergic system in the control of seasonal functions, such as reproduction, has been known for more than 4 decades, but investigations on its impact on the circadian system under normal (entrained) conditions started 2 decades later by comparing mouse strains with a fully functional melatoninergic system with mouse strains which either produce insufficient amounts of melatonin or lack the melatonin receptors MT1 and MT2. These studies revealed that an intact melatoninergic system is not required for the generation or maintenance of rhythmic behavior under physiological entrained conditions. As shown by jet lag experiments, the melatoninergic system facilitated faster re-entrainment of locomotor activity accompanied by a more rapid adaptation of the molecular clock work in the SCN. This action depended on MT2. Further studies indicated that the endogenous melatoninergic system stabilizes the locomotor activity under entrained conditions. Notably, these effects of the endogenous melatoninergic system are subtle, suggesting that other signals such as corticosterone or temperature contribute to the synchronization of locomotor activity. Outdoor experiments lasting for a whole year indicate a seasonal plasticity of the chronotype which depends on the melatoninergic system. The comparison between mice with an intact or a compromised melatoninergic system also points toward an impact of this system on sleep, memory and metabolism.
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Affiliation(s)
- Martina Pfeffer
- Institute of Anatomy II, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
- *Correspondence: Martina Pfeffer,
| | - Charlotte von Gall
- Institute of Anatomy II, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Helmut Wicht
- Dr. Senckenbergische Anatomie II, Fachbereich Medizin der Goethe-Universität, Frankfurt am Main, Germany
| | - Horst-Werner Korf
- Institute of Anatomy I, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
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4
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Gleizes M, Fonta C, Nowak LG. Inhibitors of ectonucleotidases have paradoxical effects on synaptic transmission in the mouse cortex. J Neurochem 2021; 160:305-324. [PMID: 34905223 DOI: 10.1111/jnc.15558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 12/08/2021] [Accepted: 12/09/2021] [Indexed: 11/30/2022]
Abstract
Extracellular adenosine plays prominent roles in the brain in both physiological and pathological conditions. Adenosine can be generated following the degradation of extracellular nucleotides by various types of ectonucleotidases. Several ectonucleotidases are present in the brain parenchyma: ecto-nucleotide triphosphate diphosphohydrolases 1 and 3 (NTPDase 1 and 3), ecto-nucleotide pyrophosphatase/phosphodiesterase 1 (NPP 1), ecto-5'-nucleotidase (eN), and tissue non-specific alkaline phosphatase (TNAP, whose function in the brain has received little attention). Here we examined, in a living brain preparation, the role of these ectonucleotidases in generating extracellular adenosine. We recorded local field potentials evoked by electrical stimulation of the lateral olfactory tract in the mouse piriform cortex in vitro. Variations in adenosine level were evaluated by measuring changes in presynaptic inhibition generated by adenosine A1 receptors (A1Rs) activation. A1R-mediated presynaptic inhibition was present endogenously and was enhanced by bath-applied AMP and ATP. We hypothesized that inhibiting ectonucleotidases would reduce extracellular adenosine concentration, which would result in a weakening of presynaptic inhibition. However, inhibiting TNAP had no effect in controlling endogenous adenosine action and no effect on presynaptic inhibition induced by bath-applied AMP. Furthermore, contrary to our expectation, inhibiting TNAP reinforced, rather than reduced, presynaptic inhibition induced by bath-applied ATP. Similarly, inhibition of NTPDase 1 and 3, NPP1 and eN induced stronger, rather than weaker, presynaptic inhibition, both in endogenous condition and with bath-applied ATP and AMP. Consequently, attempts to suppress the functions of extracellular adenosine by blocking its extracellular synthesis in living brain tissue could have functional impacts opposite to those anticipated.
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Affiliation(s)
- Marie Gleizes
- CerCo, Université Toulouse 3, CNRS, CHU Purpan, Pavillon Baudot, BP 25202, 31052, Toulouse Cedex
| | - Caroline Fonta
- CerCo, Université Toulouse 3, CNRS, CHU Purpan, Pavillon Baudot, BP 25202, 31052, Toulouse Cedex
| | - Lionel G Nowak
- CerCo, Université Toulouse 3, CNRS, CHU Purpan, Pavillon Baudot, BP 25202, 31052, Toulouse Cedex
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Imamura S, Tabuchi M, Oizumi H, Ueki T, Omiya Y, Ikarashi Y, Mizoguchi K. Yokukansankachimpihange, a traditional Japanese (Kampo) medicine, enhances the adaptation to circadian rhythm disruption by increasing endogenous melatonin levels. J Pharmacol Sci 2020; 144:129-138. [PMID: 32921394 DOI: 10.1016/j.jphs.2020.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 07/17/2020] [Accepted: 08/06/2020] [Indexed: 10/23/2022] Open
Abstract
The traditional Japanese (Kampo) medicines yokukansan (YKS) and yokukansankachimpihange (YKSCH) have similar formulas and the same indications. In animals or cultured cells, the neuropharmacological actions of YKS are sometimes more beneficial than those of YKSCH. Since both drugs are used to treat sleep disorders in Japan, we examined the ameliorative effects of YKS and YKSCH on circadian rhythm disturbance and compared their efficacy using a mouse model of circadian rhythm disruption. Ramelteon was used as the positive control. Ramelteon treatment significantly reversed decreased running wheel activity during the advanced dark phase, indicating facilitation of circadian adaptation. YKS treatment also reversed the activity in the early period of drug treatment; however, it was not statistically significant. YKSCH treatment significantly reversed the decreased activity during the advanced dark phase. Plasma melatonin (MT) levels were significantly increased in the YKSCH but not in the YKS group. The ameliorative effect of YKSCH on rhythm disruption was significantly inhibited by coadministration of the MT2 receptor antagonist. Therefore, the therapeutic effect of YKSCH on circadian rhythm disruption would be attributable, to elevated endogenous MT levels. Taken together, YKS and YKSCH have different pharmacological properties and may be more precisely prescribed depending on patients' psychological symptoms.
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Affiliation(s)
- Sachiko Imamura
- Tsumura Kampo Research Laboratories, Tsumura & Co., 3586 Yoshiwara, Ami-machi, Inashiki-gun, Ibaraki 300-1192, Japan.
| | - Masahiro Tabuchi
- Tsumura Kampo Research Laboratories, Tsumura & Co., 3586 Yoshiwara, Ami-machi, Inashiki-gun, Ibaraki 300-1192, Japan
| | - Hiroaki Oizumi
- Tsumura Kampo Research Laboratories, Tsumura & Co., 3586 Yoshiwara, Ami-machi, Inashiki-gun, Ibaraki 300-1192, Japan
| | - Toshiyuki Ueki
- Tsumura Kampo Research Laboratories, Tsumura & Co., 3586 Yoshiwara, Ami-machi, Inashiki-gun, Ibaraki 300-1192, Japan
| | - Yuji Omiya
- Tsumura Kampo Research Laboratories, Tsumura & Co., 3586 Yoshiwara, Ami-machi, Inashiki-gun, Ibaraki 300-1192, Japan
| | - Yasushi Ikarashi
- Tsumura Kampo Research Laboratories, Tsumura & Co., 3586 Yoshiwara, Ami-machi, Inashiki-gun, Ibaraki 300-1192, Japan
| | - Kazushige Mizoguchi
- Tsumura Kampo Research Laboratories, Tsumura & Co., 3586 Yoshiwara, Ami-machi, Inashiki-gun, Ibaraki 300-1192, Japan
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The Role of Purinergic Receptors in the Circadian System. Int J Mol Sci 2020; 21:ijms21103423. [PMID: 32408622 PMCID: PMC7279285 DOI: 10.3390/ijms21103423] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/30/2020] [Accepted: 05/06/2020] [Indexed: 12/24/2022] Open
Abstract
The circadian system is an internal time-keeping system that synchronizes the behavior and physiology of an organism to the 24 h solar day. The master circadian clock, the suprachiasmatic nucleus (SCN), resides in the hypothalamus. It receives information about the environmental light/dark conditions through the eyes and orchestrates peripheral oscillators. Purinergic signaling is mediated by extracellular purines and pyrimidines that bind to purinergic receptors and regulate multiple body functions. In this review, we highlight the interaction between the circadian system and purinergic signaling to provide a better understanding of rhythmic body functions under physiological and pathological conditions.
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Metzger J, Wicht H, Korf HW, Pfeffer M. Seasonal Variations of Locomotor Activity Rhythms in Melatonin-Proficient and -Deficient Mice under Seminatural Outdoor Conditions. J Biol Rhythms 2019; 35:58-71. [PMID: 31625428 DOI: 10.1177/0748730419881922] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Locomotor activity patterns of laboratory mice are widely used to analyze circadian mechanisms, but most investigations have been performed under standardized laboratory conditions. Outdoors, animals are exposed to daily changes in photoperiod and other abiotic cues that might influence their circadian system. To investigate how the locomotor activity patterns under outdoor conditions compare to controlled laboratory conditions, we placed 2 laboratory mouse strains (melatonin-deficient C57Bl and melatonin-proficient C3H) in the garden of the Dr. Senckenbergische Anatomie in Frankfurt am Main. The mice were kept singly in cages equipped with an infrared locomotion detector, a hiding box, nesting material, and with food and water ad libitum. The locomotor activity of each mouse was recorded for 1 year, together with data on ambient temperature, light, and humidity. Chronotype, chronotype stability, total daily activity, duration of the activity period, and daily diurnality indices were determined from the actograms. C3H mice showed clear seasonal differences in the chronotype, its stability, the total daily activity, and the duration of the activity period. These pronounced seasonal differences were not observed in the C57Bl. In both strains, the onset of the main activity period was mainly determined by the evening dusk, whereas the offset was influenced by the ambient temperature. The actograms did not reveal infra-, ultradian, or lunar rhythms or a weekday/weekend pattern. Under outdoor conditions, the 2 strains retained their nocturnal locomotor identity as observed in the laboratory. Our results indicate that the chronotype displays a seasonal plasticity that may depend on the melatoninergic system. Photoperiod and ambient temperature are the most potent abiotic entraining cues. The timing of the evening dusk mainly affects the onset of the activity period; the ambient temperature during this period influences the latter's duration. Humidity, overall light intensities, and human activities do not affect the locomotor behavior.
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Affiliation(s)
- Joshua Metzger
- Dr. Senckenbergische Anatomie II, Fachbereich Medizin, Goethe-Universität Frankfurt, Frankfurt am Main, Germany
| | - Helmut Wicht
- Dr. Senckenbergische Anatomie II, Fachbereich Medizin, Goethe-Universität Frankfurt, Frankfurt am Main, Germany
| | - Horst-Werner Korf
- Institut für Anatomie I, Fachbereich Medizin, Heinrich Heine Universität, Düsseldorf, Germany
| | - Martina Pfeffer
- Institut für Anatomie II, Fachbereich Medizin, Heinrich Heine Universität, Düsseldorf, Germany
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Pfeffer M, Korf HW, Wicht H. Synchronizing effects of melatonin on diurnal and circadian rhythms. Gen Comp Endocrinol 2018; 258:215-221. [PMID: 28533170 DOI: 10.1016/j.ygcen.2017.05.013] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 04/27/2017] [Accepted: 05/16/2017] [Indexed: 01/02/2023]
Abstract
In mammals, the rhythmic secretion of melatonin from the pineal gland is driven by the circadian clock in the suprachiasmatic nucleus (SCN) of the hypothalamus. The robust nightly peak of melatonin secretion is an output signal of the circadian clock and is supposed to deliver the circadian message to the whole of the organism. Since the circadian system regulates many behavioral and physiological processes, its disruption by external (shift-work, jet-lag) or internal desynchronization (blindness, aging) causes many different health problems. Externally applied melatonin is used in humans as a chronobiotic drug to treat desynchronization and circadian disorders, and the success of these treatments does, at first glance, underline the supposed pivotal role of melatonin in the synchronization of the circadian system. On the other hand, pinealectomy in experimental animals and humans does not abolish their rhythms of rest and activity. Furthermore, mice with deficient melatoninergic systems neither display overt defects in their rhythmic behavior nor do they show obvious signs of disease susceptibility, let alone premature mortality. During the last years, our laboratory has investigated several mouse stains with intact or compromised internal melatonin signaling systems in order to better understand the physiological role of the melatoninergic system. These and other investigations which will be reviewed in the present contribution confirm the synchronizing effect of endogenous melatonin and the melatoninergic system. However, these effects are subtle. Thus melatonin does not appear as the master of internal synchronization, but as one component in a cocktail of synchronizing agents.
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Affiliation(s)
- Martina Pfeffer
- Dr. Senckenbergische Anatomie II, Fachbereich Medizin, Goethe-Universität Frankfurt, Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany; Dr. Senckenbergisches Chronomedizinisches Institut, Goethe-Universität Frankfurt, Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany.
| | - Horst-Werner Korf
- Dr. Senckenbergische Anatomie II, Fachbereich Medizin, Goethe-Universität Frankfurt, Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany; Dr. Senckenbergisches Chronomedizinisches Institut, Goethe-Universität Frankfurt, Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany
| | - Helmut Wicht
- Dr. Senckenbergische Anatomie II, Fachbereich Medizin, Goethe-Universität Frankfurt, Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany
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9
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The P2Y 1 receptor-mediated leukocyte adhesion to endothelial cells is inhibited by melatonin. Purinergic Signal 2017; 13:331-338. [PMID: 28555330 DOI: 10.1007/s11302-017-9565-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 04/27/2017] [Indexed: 12/16/2022] Open
Abstract
Extracellular ATP (released by endothelial and immune cells) and its metabolite ADP are important pro-inflammatory mediators via the activation of purinergic P2 receptors (P2Y and P2X), which represent potential new targets for anti-inflammatory therapy. Endothelial P2Y1 receptor (P2Y1R) induces endothelial cell activation triggering leukocyte adhesion. A number of data have implicated melatonin as a modulator of immunity, inflammation, and endothelial cell function, but to date no studies have investigated whether melatonin modulates endothelial P2YR signaling. Here, we evaluated the putative effect of melatonin on P2Y1R-mediated leukocyte adhesion to endothelial cells and TNF-α production, using mesenteric endothelial cells and fresh peripheral blood mononuclear cells isolated from rats. Endothelial cells were treated with the P2Y1R agonist 2MeSATP, alone or in combination with melatonin, and then exposed to mononuclear cells. 2MeSATP increased leukocyte adhesion to endothelial cells and TNF-α production in vitro, and melatonin inhibited both effects without altering P2Y1R protein expression. In addition, assays with the Ca2+ chelator BAPTA-AM indicate that the effect of melatonin on 2MeSATP-stimulated leukocyte adhesion depends on intracellular Ca2+ modulation. P2Y1R is considered a potential target to control chronic inflammation. Therefore, our data unveiled a new endothelial cell modulator of purinergic P2Y1 receptor signaling.
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Homola M, Pfeffer M, Robson SC, Fischer C, Zimmermann H, Korf HW. Melatonin receptor deficiency decreases and temporally shifts ecto-5'-nucleotidase mRNA levels in mouse prosencephalon. Cell Tissue Res 2016; 365:147-56. [PMID: 26917036 DOI: 10.1007/s00441-016-2378-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 02/12/2016] [Indexed: 11/29/2022]
Abstract
Ecto-5'-nucleotidase (eN) is the major extracellular adenosine-producing ecto-enzyme in mouse brain. Via the production of adenosine, eN participates in many physiological and pathological processes, such as wakefulness, inflammation, nociception and neuroprotection. The mechanisms regulating the expression of eN are therefore of considerable neurobiological and clinical interest. Having previously described a modulatory effect of melatonin in the regulation of eN mRNA levels, we decided to analyze the melatonin receptor subtype involved in the regulation of eN mRNA levels by comparing eN mRNA patterns in melatonin-proficient transgenic mice lacking either the melatonin receptor subtype 1 (MT1 KO) or both melatonin receptor subtypes (MT1 and MT2; MT1/2 KO) with the corresponding melatonin-proficient wild-type (WT) controls. By means of radioactive in situ hybridization, eN mRNA levels were found to be diminished in both MT1 and MT1/2 KO mice compared with WT controls suggesting stimulatory impacts of melatonin receptors on eN mRNA levels. Whereas eN mRNA levels increased during the day and peaked at night in WT and MT1 KO mice, eN mRNA levels at night were reduced and the peak was shifted toward day-time in double MT1/2 KO mice. These data suggest that the MT2 receptor subtype may play a role in the temporal regulation of eN mRNA availability. Notably, day-time locomotor activity was significantly higher in MT1/2 KO compared with WT mice. Our results suggest melatoninergic signaling as an interface between the purinergic system and the circadian system.
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Affiliation(s)
- Moran Homola
- Institute of Anatomy II, Dr. Senckenbergisches Chronomedizinisches Institut (SCI), Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Martina Pfeffer
- Institute of Anatomy II, Dr. Senckenbergisches Chronomedizinisches Institut (SCI), Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Simon C Robson
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, 3 Blackfan Circle, Boston, MA 02215, USA
| | - Claudia Fischer
- Institute of Anatomy II, Dr. Senckenbergisches Chronomedizinisches Institut (SCI), Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Herbert Zimmermann
- Institute of Cell Biology and Neuroscience, Molecular and Cellular Neurobiology, Goethe University, Max-von-Laue-Strasse 13, 60438, Frankfurt am Main, Germany
| | - Horst-Werner Korf
- Institute of Anatomy II, Dr. Senckenbergisches Chronomedizinisches Institut (SCI), Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany.
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