Pineal melatonin in hibernating and aroused golden hamsters (Mesocricetus auratus)

Spontaneous recurrence of a summer-like diel rhythm in the body temperature of the Syrian hamster after hibernation

“…Similarly, a phase reset of the clock gene expression rhythm may occur during rewarming from the hypothermic conditions during hibernation. Melatonin in the pineal gland is maintained at low levels during HIB-DT and increases rapidly upon rewarming from HIB-DT, independent of the light–dark phase during which rewarming occurs [ 59 ]. Therefore, repeated elevation of melatonin levels during the last arousal period may contribute to the PRT.…”

Spontaneous recurrence of a summer-like diel rhythm in the body temperature of the Syrian hamster after hibernation

“…Similarly, a phase reset of the clock gene expression rhythm may occur during rewarming from the hypothermic conditions during hibernation. Melatonin in the pineal gland is maintained at low levels during HIB-DT and increases rapidly upon rewarming from HIB-DT, independent of the light–dark phase during which rewarming occurs [ 59 ]. Therefore, repeated elevation of melatonin levels during the last arousal period may contribute to the PRT.…”

Molecular Basis of White Adipose Tissue Remodeling That Precedes and Coincides With Hibernation in the Syrian Hamster, a Food-Storing Hibernator

“…Alternatively, serotonin may activate mTORC1 and PPARs in peripheral tissues of Syrian hamster during hibernation (Talaei et al, 2011; Talaei, 2014), because serotonin is reported to be an endogenous ligand for PPAR-γ (Waku et al, 2010) and the activation of serotonin receptor promotes lipogenesis in WAT of mice (Oh et al, 2015). Moreover, previous studies suggest that melatonin transduces photoperiodic stimulation to a neuroendocrine signal and could therefore control sexual activity, body mass, and hibernation in Syrian hamsters (Bartness and Wade, 1984; Vanecek et al, 1984; Pitrosky et al, 2003), which might be an upstream machinery of iWAT remodeling during the pre-HIB.…”

Pineal melatonin concentrations during day and night in the adult hedgehog: Effect of a light pulse at night and superior cervical ganglionectomy

“…In addition, as noted by Fowler himself, the absence of day-night rhythm in those data was probably due to accidental exposure of the animals to light when they were bled. Finally, during the hibernating period the state of the animals (i.e., hypothermia or euthermia) was not clearly defined and this information is necessary since during hibernation (hypothermia) it has been shown (in other species) that the day-night melatonin rhythm is abolished [Vanecek et al, 1984[Vanecek et al, , 1985Florant et al, 1984;Darrow et al, 19861. In our results, obtained in euthermic hedgehogs, there is apparently no change in amplitude of the pineal melatonin content according to season, as has been observed in euthermic marmots [Florant and Tamarkin, 19841; for confirmation the number of animals would have to be larger than that available to us.…”

Spontaneous recurrence of a summer-like diel rhythm in the body temperature of the Syrian hamster after hibernation

“…Similarly, a phase reset of the clock gene expression rhythm may occur during rewarming from the hypothermic conditions during hibernation. Melatonin in the pineal gland is maintained at low levels during HIB-DT and increases rapidly upon rewarming from HIB-DT, independent of the light–dark phase during which rewarming occurs [ 59 ]. Therefore, repeated elevation of melatonin levels during the last arousal period may contribute to the PRT.…”

Molecular Basis of White Adipose Tissue Remodeling That Precedes and Coincides With Hibernation in the Syrian Hamster, a Food-Storing Hibernator

“…Alternatively, serotonin may activate mTORC1 and PPARs in peripheral tissues of Syrian hamster during hibernation (Talaei et al, 2011; Talaei, 2014), because serotonin is reported to be an endogenous ligand for PPAR-γ (Waku et al, 2010) and the activation of serotonin receptor promotes lipogenesis in WAT of mice (Oh et al, 2015). Moreover, previous studies suggest that melatonin transduces photoperiodic stimulation to a neuroendocrine signal and could therefore control sexual activity, body mass, and hibernation in Syrian hamsters (Bartness and Wade, 1984; Vanecek et al, 1984; Pitrosky et al, 2003), which might be an upstream machinery of iWAT remodeling during the pre-HIB.…”

Pineal melatonin concentrations during day and night in the adult hedgehog: Effect of a light pulse at night and superior cervical ganglionectomy

“…In addition, as noted by Fowler himself, the absence of day-night rhythm in those data was probably due to accidental exposure of the animals to light when they were bled. Finally, during the hibernating period the state of the animals (i.e., hypothermia or euthermia) was not clearly defined and this information is necessary since during hibernation (hypothermia) it has been shown (in other species) that the day-night melatonin rhythm is abolished [Vanecek et al, 1984[Vanecek et al, , 1985Florant et al, 1984;Darrow et al, 19861. In our results, obtained in euthermic hedgehogs, there is apparently no change in amplitude of the pineal melatonin content according to season, as has been observed in euthermic marmots [Florant and Tamarkin, 19841; for confirmation the number of animals would have to be larger than that available to us.…”

Spontaneous recurrence of a summer-like diel rhythm in the body temperature of the Syrian hamster after hibernation

“…Similarly, a phase reset of the clock gene expression rhythm may occur during rewarming from the hypothermic conditions during hibernation. Melatonin in the pineal gland is maintained at low levels during HIB-DT and increases rapidly upon rewarming from HIB-DT, independent of the light–dark phase during which rewarming occurs [ 59 ]. Therefore, repeated elevation of melatonin levels during the last arousal period may contribute to the PRT.…”

Molecular Basis of White Adipose Tissue Remodeling That Precedes and Coincides With Hibernation in the Syrian Hamster, a Food-Storing Hibernator

“…Alternatively, serotonin may activate mTORC1 and PPARs in peripheral tissues of Syrian hamster during hibernation (Talaei et al, 2011; Talaei, 2014), because serotonin is reported to be an endogenous ligand for PPAR-γ (Waku et al, 2010) and the activation of serotonin receptor promotes lipogenesis in WAT of mice (Oh et al, 2015). Moreover, previous studies suggest that melatonin transduces photoperiodic stimulation to a neuroendocrine signal and could therefore control sexual activity, body mass, and hibernation in Syrian hamsters (Bartness and Wade, 1984; Vanecek et al, 1984; Pitrosky et al, 2003), which might be an upstream machinery of iWAT remodeling during the pre-HIB.…”

Pineal melatonin concentrations during day and night in the adult hedgehog: Effect of a light pulse at night and superior cervical ganglionectomy

“…In addition, as noted by Fowler himself, the absence of day-night rhythm in those data was probably due to accidental exposure of the animals to light when they were bled. Finally, during the hibernating period the state of the animals (i.e., hypothermia or euthermia) was not clearly defined and this information is necessary since during hibernation (hypothermia) it has been shown (in other species) that the day-night melatonin rhythm is abolished [Vanecek et al, 1984[Vanecek et al, , 1985Florant et al, 1984;Darrow et al, 19861. In our results, obtained in euthermic hedgehogs, there is apparently no change in amplitude of the pineal melatonin content according to season, as has been observed in euthermic marmots [Florant and Tamarkin, 19841; for confirmation the number of animals would have to be larger than that available to us.…”