The Experts below are selected from a list of 270114 Experts worldwide ranked by ideXlab platform
Antonio A. Nunez - One of the best experts on this subject based on the ideXlab platform.
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Plastic oscillators and fixed rhythms: changes in the phase of clock-gene rhythms in the PVN are not reflected in the phase of the melatonin rhythm of grass rats.
Neuroscience, 2015Co-Authors: Carmel A. Martin-fairey, Chidambaram Ramanathan, Adam Stowie, Erin J. Walaszczyk, Laura Smale, Antonio A. NunezAbstract:Abstract The same clock-genes, including Period (PER) 1 and 2, that show rhythmic expression in the suprachiasmatic nucleus (SCN) are also rhythmically expressed in other brain regions that serve as extra-SCN oscillators. Outside the hypothalamus, the phase of these extra-SCN oscillators appears to be reversed when diurnal and nocturnal mammals are compared. Based on mRNA data, PER1 Protein is expected to peak in the late night in the paraventricular nucleus of the hypothalamus (PVN) of nocturnal laboratory rats, but comparable data are not available for a diurnal species. Here we use the diurnal grass rat ( Arvicanthis niloticus ) to describe rhythms of PER1 and 2 Proteins in the PVN of animals that either show the species-typical day-active (DA) profile, or that adopt a night-active (NA) profile when given access to running wheels. For DA animals housed with or without wheels, significant rhythms of PER1 or PER2 Protein expression featured peaks in the late morning; NA animals showed patterns similar to those expected from nocturnal laboratory rats. Since the PVN is part of the circuit that controls pineal rhythms, we also measured circulating levels of melatonin during the day and night in DA animals with and without wheels and in NA wheel runners. All three groups showed elevated levels of melatonin at night, with higher levels during both the day and night being associated with the levels of activity displayed by each group. The differential phase of rhythms in the clock-gene Protein in the PVN of diurnal and nocturnal animals presents a possible mechanism for explaining species differences in the phase of autonomic rhythms controlled, in part, by the PVN. The present study suggests that the phase of the oscillator of the PVN does not determine that of the melatonin rhythm in diurnal and nocturnal species or in diurnal and nocturnal chronotypes within a species.
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Plastic oscillators and fixed rhythms: changes in the phase of clock-gene rhythms in the PVN are not reflected in the phase of the melatonin rhythm of grass rats.
Neuroscience, 2015Co-Authors: Carmel A. Martin-fairey, Chidambaram Ramanathan, Adam Stowie, Erin J. Walaszczyk, Laura Smale, Antonio A. NunezAbstract:Abstract The same clock-genes, including Period (PER) 1 and 2, that show rhythmic expression in the suprachiasmatic nucleus (SCN) are also rhythmically expressed in other brain regions that serve as extra-SCN oscillators. Outside the hypothalamus, the phase of these extra-SCN oscillators appears to be reversed when diurnal and nocturnal mammals are compared. Based on mRNA data, PER1 Protein is expected to peak in the late night in the paraventricular nucleus of the hypothalamus (PVN) of nocturnal laboratory rats, but comparable data are not available for a diurnal species. Here we use the diurnal grass rat ( Arvicanthis niloticus ) to describe rhythms of PER1 and 2 Proteins in the PVN of animals that either show the species-typical day-active (DA) profile, or that adopt a night-active (NA) profile when given access to running wheels. For DA animals housed with or without wheels, significant rhythms of PER1 or PER2 Protein expression featured peaks in the late morning; NA animals showed patterns similar to those expected from nocturnal laboratory rats. Since the PVN is part of the circuit that controls pineal rhythms, we also measured circulating levels of melatonin during the day and night in DA animals with and without wheels and in NA wheel runners. All three groups showed elevated levels of melatonin at night, with higher levels during both the day and night being associated with the levels of activity displayed by each group. The differential phase of rhythms in the clock-gene Protein in the PVN of diurnal and nocturnal animals presents a possible mechanism for explaining species differences in the phase of autonomic rhythms controlled, in part, by the PVN. The present study suggests that the phase of the oscillator of the PVN does not determine that of the melatonin rhythm in diurnal and nocturnal species or in diurnal and nocturnal chronotypes within a species.
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DAILY RHYTHMS IN PER1 WITHIN AND BEYOND THE SUPRACHIASMATIC NUCLEUS OF FEMALE GRASS RATS (ARVICANTHIS NILOTICUS)
Neuroscience, 2008Co-Authors: Chidambaram Ramanathan, Antonio A. Nunez, Laura SmaleAbstract:Although circadian rhythms of males and females are different in a variety of ways in many species, their mechanisms have been primarily studied in males. Furthermore, rhythms are dramatically different in diurnal and nocturnal animals but have been studied predominantly in nocturnal ones. In the present study, we examined rhythms in one element of the circadian oscillator, the PER1 Protein, in a variety of cell populations in brains of diurnal female grass rats. Every 4 h five adult female grass rats kept on a 12-h light/dark (LD) cycle were perfused and their brains were processed for immunohistochemical detection of PER1. Numbers of PER1-labeled cells were rhythmic not only within the suprachiasmatic nucleus (SCN), the locus of the primary circadian clock in mammals, but also in the peri-suprachiasmatic region, the oval nucleus of the bed nucleus of the stria terminalis, the central amygdala, and the nucleus accumbens. In addition, rhythms were detected within populations of neuroendocrine cells that contain tyrosine hydroxylase. The phase of the rhythm within the SCN was advanced compared with that seen previously in male grass rats. Rhythms beyond the SCN were varied and different from those seen in most nocturnal species, suggesting that signals originating in the SCN are modified by its direct and/or indirect targets in different ways in nocturnal and diurnal species.
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Rhythms in expression of PER1 Protein in the amygdala and bed nucleus of the stria terminalis of the diurnal grass rat (Arvicanthis niloticus).
Neuroscience letters, 2008Co-Authors: Chidambaram Ramanathan, Laura Smale, Antonio A. NunezAbstract:In the diurnal rodent Arvicanthis niloticus (grass rats) the pattern of expression of the clock genes and their Proteins in the suprachiasmatic nucleus (SCN) is very similar to that seen in nocturnal rodents. Rhythms in clock gene expression have been also documented in several forebrain regions outside the SCN in nocturnal Ratus norvegicus (lab rats). To investigate the neural basis for differences in the circadian systems of diurnal and nocturnal mammals, we examined PER1 expression in the oval nucleus of the bed nucleus of the stria terminalis (BNST-OV), and in the basolateral (BLA) and the central (CEA) amygdala of male grass rats kept in a 12:12 light/dark cycle. In the BNST-OV, peak levels of PER1 expression were seen early in the light phase of the cycle, 12 h out of phase with what has been reported for nocturnal lab rats. In the BLA the pattern of PER1 expression featured sustained high levels during the day and low levels at night. PER1 expression in the CEA was also at its highest early in the light phase, but the effect of sampling time was not statistically significant (p < 0.06). The results are consistent with the hypothesis that differences between nocturnal and diurnal species are due to differences in neural systems downstream from the SCN.
Mario Caba - One of the best experts on this subject based on the ideXlab platform.
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Circadian Rhythms and Clock Genes in Reproduction: Insights From Behavior and the Female Rabbit’s Brain
Frontiers in Endocrinology, 2018Co-Authors: Mario Caba, Gabriela González-mariscal, Enrique MezaAbstract:Clock gene oscillations are necessary for a successful pregnancy and parturition, but little is known about their function during lactation, a period demanding from the mother multiple physiological and behavioral adaptations to fulfill the requirements of the offspring. First we will focus on circadian rhythms and clock genes in reproductive tissues mainly in rodents. Disruption of circadian rhythms or proper rhythmic oscillations of clock genes provoke reproductive problems, as found in clock gene knockout mice. Then we will focus mainly on the rabbit doe as this mammal nurses the young just once a day with circadian periodicity. This daily event synchronizes behavior and the activity of specific brain regions critical for reproductive neuroendocrinology and maternal behavior, like the preoptic area. This region shows strong rhythms of the PER1 Protein (product of the PER1 clock gene) associated with circadian nursing. Additionally, neuroendocrine cells related to milk production and ejection are also synchronized to daily nursing. A threshold of suckling is necessary to entrain once a day nursing; this process is independent of milk output as even virgin does (behaving maternally following anosmia) can display circadian nursing behavior. A timing motivational mechanism may regulate such behavior as mesolimbic dopaminergic cells are entrained by daily nursing. Finally we will explore about the clinical importance of circadian rhythms. Indeed, women in chronic shift-work schedules show problems in their menstrual cycles and pregnancies and also have a high risk of preterm delivery, making this an important field of translational research.
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suckling induces a daily rhythm in the preoptic area and lateral septum but not in the bed nucleus of the stria terminalis in lactating rabbit does
European Journal of Neuroscience, 2015Co-Authors: Enrique Meza, Stefan M. Waliszewski, Juan Corral Aguirre, Mario CabaAbstract:Maternal behavior in the rabbit is restricted to a brief nursing period every day. Previously, we demonstrated that this event induces daily rhythms of Period1 (PER1) Protein, the product of the clock gene PER1, in oxytocinergic and dopaminergic populations in the hypothalamus of lactating rabbit does. This is significant for the periodic production and ejection of milk, but the activation of other areas of the brain has not been explored. Here, we hypothesised that daily suckling would induce a rhythm in the preoptic area, lateral septum, and bed nucleus of the stria terminalis, which are important areas for the expression of maternal behavior in mammals, including the rabbit. To this end, we analysed PER1 expression in those areas through a complete 24-h cycle at lactation day 7. Does were scheduled to nurse during either the day at 10:00 h [zeitgeber time (ZT)03] or the night at 02:00 h (ZT19). Non-pregnant, non-lactating females were used as controls. In contrast to control females, lactating does showed a clear, significant rhythm of PER1 that shifted in parallel with the timing of nursing in the preoptic area and lateral septum. We determined that the maximal expression of PER1 at 8 h after scheduled nursing decreased significantly at 24 and 48 h after the absence of suckling. This effect was more pronounced in the lateral septum than in the preoptic area. We conclude that daily suckling is a powerful stimulus inducing rhythmic activity in brain structures in the rabbit that appear to form part of a maternal entrainable circuit.
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The median preoptic nucleus exhibits circadian regulation and is involved in food anticipatory activity in rabbit pups.
Chronobiology international, 2014Co-Authors: María Luisa Moreno, Enrique Meza, Arturo Ortega, Mario CabaAbstract:Rabbit pups are a natural model to study food anticipatory activity (FAA). Recently, we reported that three areas in the forebrain - the organum vasculosum of lamina terminalis, median preoptic nucleus (MnPO) and medial preoptic area - exhibit activation during FAA. Here, we examined the PER1 Protein profile of these three forebrain regions in both nursed and fasted subjects. We found robust PER1 oscillations in the MnPO in nursed subjects, with high PER1 levels during FAA that persisted in fasted subjects. In conclusion, our data indicate that periodic nursing is a strong signal for PER1 oscillations in MnPO and future experiments are warranted to explore the specific role of this area in FAA.
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Synchronization of PER1 Protein in parabrachial nucleus in a natural model of food anticipatory activity.
The European journal of neuroscience, 2012Co-Authors: Claudia Juárez, Enrique Meza, Stefan M. Waliszewski, Elvira Morgado, Armando J. Martínez, Mario CabaAbstract:Rabbit pups represent a natural model of food anticipatory activity (FAA). FAA is the behavioral output of a putative food entrainable oscillator (FEO). It had been suggested that the FEO is comprised of a distributed system of clocks that work in concert in response to gastrointestinal input by food. Scheduled food intake synchronizes several nuclei in the brain, and the hypothalamus has received particular attention. On the contrary, brainstem nuclei, despite being among the brain structures to first receive food cues, have been scarcely studied. Here we analyzed by immunohistochemistry possible oscillation of FOS and PER1 Proteins through a complete 24 h cycle in the dorsal vagal complex (DVC) and parabrachial nucleus (PBN) of seven to eight day old rabbit pups scheduled to nurse during the night (02:00) or day (10:00) and also in fasted subjects to explore the possible persistence of oscillations. We found a clear induction of FOS that peaks 1.5 h after nursing in all nuclei studied. PER1 was only synchronized in the PBN, reaching highest values 12 h after nursing. Only PER1 oscillations persisted in fasted subjects. We conclude that the DVC nuclei are probably more related to the transmission of food cues to other brain regions but that the PBN participates in the integration of information essential for FAA. Our results support previous findings suggesting that the DVC nuclei, but not PBN, are not essential for FAA. We suggest that PBN is a key component of the proposed distributed system of clocks involved in FAA.
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Circadian nursing induces PER1 Protein in neuroendocrine tyrosine hydroxylase neurones in the rabbit doe.
Journal of neuroendocrinology, 2011Co-Authors: Enrique Meza, Stefan M. Waliszewski, Mario CabaAbstract:Rabbit does nurse their pups once a day with circadian periodicity and pups ingest up to 35% of their body weight in milk in < 5 min. In the doe, there is a massive release of prolactin. We hypothesised that periodic suckling synchronises dopaminergic populations that control prolactin secretion. We explored this by immunohistochemical colocalisation of PER1 Protein, the product of the clock gene PER1 on tyrosine hydroxylase (TH) cells in three dopaminergic populations: tuberoinfundibular dopaminergic (TIDA), periventricular hypophyseal dopaminergic (PHDA) and incertohypothalamic dopaminergic (IHDA) cells. PER1/TH colocalisation was explored every 4 h through a complete 24-h cycle at postpartum day 7 in does that nursed their pups either at 10.00 h (ZT03) or at 02.00 h (ZT19; ZTO = 07.00 h, time of lights on). Nonpregnant, nonlactating females were used as controls. In control females, there was a rhythm of PER1 that peaks at ZT15. By contrast, in nursed does, the PER1 peak shifted in parallel to scheduled nursing in TIDA and PHDA cells but not in IHDA cells, which are not related to the control of prolactin. Next, we determined that the absence of suckling for 48 h significantly decreases the number of PER1/TH colocalised cells in PHDA but not TIDA cells. Locomotor behaviour in control subjects was maximal at around the time of lights on but, in nursed females, shifted at around the time of scheduled nursing. Finally, in the suprachiasmatic nucleus, there is a maximal expression of PER1 at ZT11 in the three groups. However, this maximal expression was significantly lower in the nursed groups in relation to the control group and in the groups deprived of nursing for 48 h. We conclude that suckling synchronises dopaminergic cells related to the control of prolactin and appears to be a nonphotic stimulus for the suprachiasmatic nucleus.
Laura Smale - One of the best experts on this subject based on the ideXlab platform.
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Plastic oscillators and fixed rhythms: changes in the phase of clock-gene rhythms in the PVN are not reflected in the phase of the melatonin rhythm of grass rats.
Neuroscience, 2015Co-Authors: Carmel A. Martin-fairey, Chidambaram Ramanathan, Adam Stowie, Erin J. Walaszczyk, Laura Smale, Antonio A. NunezAbstract:Abstract The same clock-genes, including Period (PER) 1 and 2, that show rhythmic expression in the suprachiasmatic nucleus (SCN) are also rhythmically expressed in other brain regions that serve as extra-SCN oscillators. Outside the hypothalamus, the phase of these extra-SCN oscillators appears to be reversed when diurnal and nocturnal mammals are compared. Based on mRNA data, PER1 Protein is expected to peak in the late night in the paraventricular nucleus of the hypothalamus (PVN) of nocturnal laboratory rats, but comparable data are not available for a diurnal species. Here we use the diurnal grass rat ( Arvicanthis niloticus ) to describe rhythms of PER1 and 2 Proteins in the PVN of animals that either show the species-typical day-active (DA) profile, or that adopt a night-active (NA) profile when given access to running wheels. For DA animals housed with or without wheels, significant rhythms of PER1 or PER2 Protein expression featured peaks in the late morning; NA animals showed patterns similar to those expected from nocturnal laboratory rats. Since the PVN is part of the circuit that controls pineal rhythms, we also measured circulating levels of melatonin during the day and night in DA animals with and without wheels and in NA wheel runners. All three groups showed elevated levels of melatonin at night, with higher levels during both the day and night being associated with the levels of activity displayed by each group. The differential phase of rhythms in the clock-gene Protein in the PVN of diurnal and nocturnal animals presents a possible mechanism for explaining species differences in the phase of autonomic rhythms controlled, in part, by the PVN. The present study suggests that the phase of the oscillator of the PVN does not determine that of the melatonin rhythm in diurnal and nocturnal species or in diurnal and nocturnal chronotypes within a species.
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Plastic oscillators and fixed rhythms: changes in the phase of clock-gene rhythms in the PVN are not reflected in the phase of the melatonin rhythm of grass rats.
Neuroscience, 2015Co-Authors: Carmel A. Martin-fairey, Chidambaram Ramanathan, Adam Stowie, Erin J. Walaszczyk, Laura Smale, Antonio A. NunezAbstract:Abstract The same clock-genes, including Period (PER) 1 and 2, that show rhythmic expression in the suprachiasmatic nucleus (SCN) are also rhythmically expressed in other brain regions that serve as extra-SCN oscillators. Outside the hypothalamus, the phase of these extra-SCN oscillators appears to be reversed when diurnal and nocturnal mammals are compared. Based on mRNA data, PER1 Protein is expected to peak in the late night in the paraventricular nucleus of the hypothalamus (PVN) of nocturnal laboratory rats, but comparable data are not available for a diurnal species. Here we use the diurnal grass rat ( Arvicanthis niloticus ) to describe rhythms of PER1 and 2 Proteins in the PVN of animals that either show the species-typical day-active (DA) profile, or that adopt a night-active (NA) profile when given access to running wheels. For DA animals housed with or without wheels, significant rhythms of PER1 or PER2 Protein expression featured peaks in the late morning; NA animals showed patterns similar to those expected from nocturnal laboratory rats. Since the PVN is part of the circuit that controls pineal rhythms, we also measured circulating levels of melatonin during the day and night in DA animals with and without wheels and in NA wheel runners. All three groups showed elevated levels of melatonin at night, with higher levels during both the day and night being associated with the levels of activity displayed by each group. The differential phase of rhythms in the clock-gene Protein in the PVN of diurnal and nocturnal animals presents a possible mechanism for explaining species differences in the phase of autonomic rhythms controlled, in part, by the PVN. The present study suggests that the phase of the oscillator of the PVN does not determine that of the melatonin rhythm in diurnal and nocturnal species or in diurnal and nocturnal chronotypes within a species.
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DAILY RHYTHMS IN PER1 WITHIN AND BEYOND THE SUPRACHIASMATIC NUCLEUS OF FEMALE GRASS RATS (ARVICANTHIS NILOTICUS)
Neuroscience, 2008Co-Authors: Chidambaram Ramanathan, Antonio A. Nunez, Laura SmaleAbstract:Although circadian rhythms of males and females are different in a variety of ways in many species, their mechanisms have been primarily studied in males. Furthermore, rhythms are dramatically different in diurnal and nocturnal animals but have been studied predominantly in nocturnal ones. In the present study, we examined rhythms in one element of the circadian oscillator, the PER1 Protein, in a variety of cell populations in brains of diurnal female grass rats. Every 4 h five adult female grass rats kept on a 12-h light/dark (LD) cycle were perfused and their brains were processed for immunohistochemical detection of PER1. Numbers of PER1-labeled cells were rhythmic not only within the suprachiasmatic nucleus (SCN), the locus of the primary circadian clock in mammals, but also in the peri-suprachiasmatic region, the oval nucleus of the bed nucleus of the stria terminalis, the central amygdala, and the nucleus accumbens. In addition, rhythms were detected within populations of neuroendocrine cells that contain tyrosine hydroxylase. The phase of the rhythm within the SCN was advanced compared with that seen previously in male grass rats. Rhythms beyond the SCN were varied and different from those seen in most nocturnal species, suggesting that signals originating in the SCN are modified by its direct and/or indirect targets in different ways in nocturnal and diurnal species.
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Rhythms in expression of PER1 Protein in the amygdala and bed nucleus of the stria terminalis of the diurnal grass rat (Arvicanthis niloticus).
Neuroscience letters, 2008Co-Authors: Chidambaram Ramanathan, Laura Smale, Antonio A. NunezAbstract:In the diurnal rodent Arvicanthis niloticus (grass rats) the pattern of expression of the clock genes and their Proteins in the suprachiasmatic nucleus (SCN) is very similar to that seen in nocturnal rodents. Rhythms in clock gene expression have been also documented in several forebrain regions outside the SCN in nocturnal Ratus norvegicus (lab rats). To investigate the neural basis for differences in the circadian systems of diurnal and nocturnal mammals, we examined PER1 expression in the oval nucleus of the bed nucleus of the stria terminalis (BNST-OV), and in the basolateral (BLA) and the central (CEA) amygdala of male grass rats kept in a 12:12 light/dark cycle. In the BNST-OV, peak levels of PER1 expression were seen early in the light phase of the cycle, 12 h out of phase with what has been reported for nocturnal lab rats. In the BLA the pattern of PER1 expression featured sustained high levels during the day and low levels at night. PER1 expression in the CEA was also at its highest early in the light phase, but the effect of sampling time was not statistically significant (p < 0.06). The results are consistent with the hypothesis that differences between nocturnal and diurnal species are due to differences in neural systems downstream from the SCN.
Chidambaram Ramanathan - One of the best experts on this subject based on the ideXlab platform.
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Plastic oscillators and fixed rhythms: changes in the phase of clock-gene rhythms in the PVN are not reflected in the phase of the melatonin rhythm of grass rats.
Neuroscience, 2015Co-Authors: Carmel A. Martin-fairey, Chidambaram Ramanathan, Adam Stowie, Erin J. Walaszczyk, Laura Smale, Antonio A. NunezAbstract:Abstract The same clock-genes, including Period (PER) 1 and 2, that show rhythmic expression in the suprachiasmatic nucleus (SCN) are also rhythmically expressed in other brain regions that serve as extra-SCN oscillators. Outside the hypothalamus, the phase of these extra-SCN oscillators appears to be reversed when diurnal and nocturnal mammals are compared. Based on mRNA data, PER1 Protein is expected to peak in the late night in the paraventricular nucleus of the hypothalamus (PVN) of nocturnal laboratory rats, but comparable data are not available for a diurnal species. Here we use the diurnal grass rat ( Arvicanthis niloticus ) to describe rhythms of PER1 and 2 Proteins in the PVN of animals that either show the species-typical day-active (DA) profile, or that adopt a night-active (NA) profile when given access to running wheels. For DA animals housed with or without wheels, significant rhythms of PER1 or PER2 Protein expression featured peaks in the late morning; NA animals showed patterns similar to those expected from nocturnal laboratory rats. Since the PVN is part of the circuit that controls pineal rhythms, we also measured circulating levels of melatonin during the day and night in DA animals with and without wheels and in NA wheel runners. All three groups showed elevated levels of melatonin at night, with higher levels during both the day and night being associated with the levels of activity displayed by each group. The differential phase of rhythms in the clock-gene Protein in the PVN of diurnal and nocturnal animals presents a possible mechanism for explaining species differences in the phase of autonomic rhythms controlled, in part, by the PVN. The present study suggests that the phase of the oscillator of the PVN does not determine that of the melatonin rhythm in diurnal and nocturnal species or in diurnal and nocturnal chronotypes within a species.
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Plastic oscillators and fixed rhythms: changes in the phase of clock-gene rhythms in the PVN are not reflected in the phase of the melatonin rhythm of grass rats.
Neuroscience, 2015Co-Authors: Carmel A. Martin-fairey, Chidambaram Ramanathan, Adam Stowie, Erin J. Walaszczyk, Laura Smale, Antonio A. NunezAbstract:Abstract The same clock-genes, including Period (PER) 1 and 2, that show rhythmic expression in the suprachiasmatic nucleus (SCN) are also rhythmically expressed in other brain regions that serve as extra-SCN oscillators. Outside the hypothalamus, the phase of these extra-SCN oscillators appears to be reversed when diurnal and nocturnal mammals are compared. Based on mRNA data, PER1 Protein is expected to peak in the late night in the paraventricular nucleus of the hypothalamus (PVN) of nocturnal laboratory rats, but comparable data are not available for a diurnal species. Here we use the diurnal grass rat ( Arvicanthis niloticus ) to describe rhythms of PER1 and 2 Proteins in the PVN of animals that either show the species-typical day-active (DA) profile, or that adopt a night-active (NA) profile when given access to running wheels. For DA animals housed with or without wheels, significant rhythms of PER1 or PER2 Protein expression featured peaks in the late morning; NA animals showed patterns similar to those expected from nocturnal laboratory rats. Since the PVN is part of the circuit that controls pineal rhythms, we also measured circulating levels of melatonin during the day and night in DA animals with and without wheels and in NA wheel runners. All three groups showed elevated levels of melatonin at night, with higher levels during both the day and night being associated with the levels of activity displayed by each group. The differential phase of rhythms in the clock-gene Protein in the PVN of diurnal and nocturnal animals presents a possible mechanism for explaining species differences in the phase of autonomic rhythms controlled, in part, by the PVN. The present study suggests that the phase of the oscillator of the PVN does not determine that of the melatonin rhythm in diurnal and nocturnal species or in diurnal and nocturnal chronotypes within a species.
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DAILY RHYTHMS IN PER1 WITHIN AND BEYOND THE SUPRACHIASMATIC NUCLEUS OF FEMALE GRASS RATS (ARVICANTHIS NILOTICUS)
Neuroscience, 2008Co-Authors: Chidambaram Ramanathan, Antonio A. Nunez, Laura SmaleAbstract:Although circadian rhythms of males and females are different in a variety of ways in many species, their mechanisms have been primarily studied in males. Furthermore, rhythms are dramatically different in diurnal and nocturnal animals but have been studied predominantly in nocturnal ones. In the present study, we examined rhythms in one element of the circadian oscillator, the PER1 Protein, in a variety of cell populations in brains of diurnal female grass rats. Every 4 h five adult female grass rats kept on a 12-h light/dark (LD) cycle were perfused and their brains were processed for immunohistochemical detection of PER1. Numbers of PER1-labeled cells were rhythmic not only within the suprachiasmatic nucleus (SCN), the locus of the primary circadian clock in mammals, but also in the peri-suprachiasmatic region, the oval nucleus of the bed nucleus of the stria terminalis, the central amygdala, and the nucleus accumbens. In addition, rhythms were detected within populations of neuroendocrine cells that contain tyrosine hydroxylase. The phase of the rhythm within the SCN was advanced compared with that seen previously in male grass rats. Rhythms beyond the SCN were varied and different from those seen in most nocturnal species, suggesting that signals originating in the SCN are modified by its direct and/or indirect targets in different ways in nocturnal and diurnal species.
-
Rhythms in expression of PER1 Protein in the amygdala and bed nucleus of the stria terminalis of the diurnal grass rat (Arvicanthis niloticus).
Neuroscience letters, 2008Co-Authors: Chidambaram Ramanathan, Laura Smale, Antonio A. NunezAbstract:In the diurnal rodent Arvicanthis niloticus (grass rats) the pattern of expression of the clock genes and their Proteins in the suprachiasmatic nucleus (SCN) is very similar to that seen in nocturnal rodents. Rhythms in clock gene expression have been also documented in several forebrain regions outside the SCN in nocturnal Ratus norvegicus (lab rats). To investigate the neural basis for differences in the circadian systems of diurnal and nocturnal mammals, we examined PER1 expression in the oval nucleus of the bed nucleus of the stria terminalis (BNST-OV), and in the basolateral (BLA) and the central (CEA) amygdala of male grass rats kept in a 12:12 light/dark cycle. In the BNST-OV, peak levels of PER1 expression were seen early in the light phase of the cycle, 12 h out of phase with what has been reported for nocturnal lab rats. In the BLA the pattern of PER1 expression featured sustained high levels during the day and low levels at night. PER1 expression in the CEA was also at its highest early in the light phase, but the effect of sampling time was not statistically significant (p < 0.06). The results are consistent with the hypothesis that differences between nocturnal and diurnal species are due to differences in neural systems downstream from the SCN.
Enrique Meza - One of the best experts on this subject based on the ideXlab platform.
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Circadian Rhythms and Clock Genes in Reproduction: Insights From Behavior and the Female Rabbit’s Brain
Frontiers in Endocrinology, 2018Co-Authors: Mario Caba, Gabriela González-mariscal, Enrique MezaAbstract:Clock gene oscillations are necessary for a successful pregnancy and parturition, but little is known about their function during lactation, a period demanding from the mother multiple physiological and behavioral adaptations to fulfill the requirements of the offspring. First we will focus on circadian rhythms and clock genes in reproductive tissues mainly in rodents. Disruption of circadian rhythms or proper rhythmic oscillations of clock genes provoke reproductive problems, as found in clock gene knockout mice. Then we will focus mainly on the rabbit doe as this mammal nurses the young just once a day with circadian periodicity. This daily event synchronizes behavior and the activity of specific brain regions critical for reproductive neuroendocrinology and maternal behavior, like the preoptic area. This region shows strong rhythms of the PER1 Protein (product of the PER1 clock gene) associated with circadian nursing. Additionally, neuroendocrine cells related to milk production and ejection are also synchronized to daily nursing. A threshold of suckling is necessary to entrain once a day nursing; this process is independent of milk output as even virgin does (behaving maternally following anosmia) can display circadian nursing behavior. A timing motivational mechanism may regulate such behavior as mesolimbic dopaminergic cells are entrained by daily nursing. Finally we will explore about the clinical importance of circadian rhythms. Indeed, women in chronic shift-work schedules show problems in their menstrual cycles and pregnancies and also have a high risk of preterm delivery, making this an important field of translational research.
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suckling induces a daily rhythm in the preoptic area and lateral septum but not in the bed nucleus of the stria terminalis in lactating rabbit does
European Journal of Neuroscience, 2015Co-Authors: Enrique Meza, Stefan M. Waliszewski, Juan Corral Aguirre, Mario CabaAbstract:Maternal behavior in the rabbit is restricted to a brief nursing period every day. Previously, we demonstrated that this event induces daily rhythms of Period1 (PER1) Protein, the product of the clock gene PER1, in oxytocinergic and dopaminergic populations in the hypothalamus of lactating rabbit does. This is significant for the periodic production and ejection of milk, but the activation of other areas of the brain has not been explored. Here, we hypothesised that daily suckling would induce a rhythm in the preoptic area, lateral septum, and bed nucleus of the stria terminalis, which are important areas for the expression of maternal behavior in mammals, including the rabbit. To this end, we analysed PER1 expression in those areas through a complete 24-h cycle at lactation day 7. Does were scheduled to nurse during either the day at 10:00 h [zeitgeber time (ZT)03] or the night at 02:00 h (ZT19). Non-pregnant, non-lactating females were used as controls. In contrast to control females, lactating does showed a clear, significant rhythm of PER1 that shifted in parallel with the timing of nursing in the preoptic area and lateral septum. We determined that the maximal expression of PER1 at 8 h after scheduled nursing decreased significantly at 24 and 48 h after the absence of suckling. This effect was more pronounced in the lateral septum than in the preoptic area. We conclude that daily suckling is a powerful stimulus inducing rhythmic activity in brain structures in the rabbit that appear to form part of a maternal entrainable circuit.
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The median preoptic nucleus exhibits circadian regulation and is involved in food anticipatory activity in rabbit pups.
Chronobiology international, 2014Co-Authors: María Luisa Moreno, Enrique Meza, Arturo Ortega, Mario CabaAbstract:Rabbit pups are a natural model to study food anticipatory activity (FAA). Recently, we reported that three areas in the forebrain - the organum vasculosum of lamina terminalis, median preoptic nucleus (MnPO) and medial preoptic area - exhibit activation during FAA. Here, we examined the PER1 Protein profile of these three forebrain regions in both nursed and fasted subjects. We found robust PER1 oscillations in the MnPO in nursed subjects, with high PER1 levels during FAA that persisted in fasted subjects. In conclusion, our data indicate that periodic nursing is a strong signal for PER1 oscillations in MnPO and future experiments are warranted to explore the specific role of this area in FAA.
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Synchronization of PER1 Protein in parabrachial nucleus in a natural model of food anticipatory activity.
The European journal of neuroscience, 2012Co-Authors: Claudia Juárez, Enrique Meza, Stefan M. Waliszewski, Elvira Morgado, Armando J. Martínez, Mario CabaAbstract:Rabbit pups represent a natural model of food anticipatory activity (FAA). FAA is the behavioral output of a putative food entrainable oscillator (FEO). It had been suggested that the FEO is comprised of a distributed system of clocks that work in concert in response to gastrointestinal input by food. Scheduled food intake synchronizes several nuclei in the brain, and the hypothalamus has received particular attention. On the contrary, brainstem nuclei, despite being among the brain structures to first receive food cues, have been scarcely studied. Here we analyzed by immunohistochemistry possible oscillation of FOS and PER1 Proteins through a complete 24 h cycle in the dorsal vagal complex (DVC) and parabrachial nucleus (PBN) of seven to eight day old rabbit pups scheduled to nurse during the night (02:00) or day (10:00) and also in fasted subjects to explore the possible persistence of oscillations. We found a clear induction of FOS that peaks 1.5 h after nursing in all nuclei studied. PER1 was only synchronized in the PBN, reaching highest values 12 h after nursing. Only PER1 oscillations persisted in fasted subjects. We conclude that the DVC nuclei are probably more related to the transmission of food cues to other brain regions but that the PBN participates in the integration of information essential for FAA. Our results support previous findings suggesting that the DVC nuclei, but not PBN, are not essential for FAA. We suggest that PBN is a key component of the proposed distributed system of clocks involved in FAA.
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Circadian nursing induces PER1 Protein in neuroendocrine tyrosine hydroxylase neurones in the rabbit doe.
Journal of neuroendocrinology, 2011Co-Authors: Enrique Meza, Stefan M. Waliszewski, Mario CabaAbstract:Rabbit does nurse their pups once a day with circadian periodicity and pups ingest up to 35% of their body weight in milk in < 5 min. In the doe, there is a massive release of prolactin. We hypothesised that periodic suckling synchronises dopaminergic populations that control prolactin secretion. We explored this by immunohistochemical colocalisation of PER1 Protein, the product of the clock gene PER1 on tyrosine hydroxylase (TH) cells in three dopaminergic populations: tuberoinfundibular dopaminergic (TIDA), periventricular hypophyseal dopaminergic (PHDA) and incertohypothalamic dopaminergic (IHDA) cells. PER1/TH colocalisation was explored every 4 h through a complete 24-h cycle at postpartum day 7 in does that nursed their pups either at 10.00 h (ZT03) or at 02.00 h (ZT19; ZTO = 07.00 h, time of lights on). Nonpregnant, nonlactating females were used as controls. In control females, there was a rhythm of PER1 that peaks at ZT15. By contrast, in nursed does, the PER1 peak shifted in parallel to scheduled nursing in TIDA and PHDA cells but not in IHDA cells, which are not related to the control of prolactin. Next, we determined that the absence of suckling for 48 h significantly decreases the number of PER1/TH colocalised cells in PHDA but not TIDA cells. Locomotor behaviour in control subjects was maximal at around the time of lights on but, in nursed females, shifted at around the time of scheduled nursing. Finally, in the suprachiasmatic nucleus, there is a maximal expression of PER1 at ZT11 in the three groups. However, this maximal expression was significantly lower in the nursed groups in relation to the control group and in the groups deprived of nursing for 48 h. We conclude that suckling synchronises dopaminergic cells related to the control of prolactin and appears to be a nonphotic stimulus for the suprachiasmatic nucleus.