Increased photic sensitivity for phase resetting but not melatonin suppression in Siberian hamsters under short photoperiods
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منابع مشابه
Increased photic sensitivity for phase resetting but not melatonin suppression in Siberian hamsters under short photoperiods.
Light regulates a variety of behavioral and physiological processes, including activity rhythms and hormone secretory patterns. Seasonal changes in the proportion of light in a day (photoperiod) further modulate those functions. Recently, short (SP) versus long days (LP) were found to markedly increase light sensitivity for phase shifting in Syrian hamsters. To our knowledge, photoperiod effect...
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Body temperature (Tb) was recorded via a biotelemetry system from 28 adult male Siberian hamsters maintained in a light-dark (LD) cycle of 16 h light/day for several months. After Tb was recorded for 3 wk, the LD cycle was phase delayed by extending the light phase by 5 h for 1 day; animals remained on a 16:8 LD cycle for the remainder of the experiment. Hamsters were injected daily with melato...
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Short days induce winter-like adaptations in small mammals such as Siberian hamsters (Phodopus sungorus (Pallas, 1773)). Specifically, hamsters adjust food consumption, metabolic processes, and immune function to optimize energetic needs and promote winter survival. One potentially inexpensive behavioral adaptation to increase survival is avoidance of infection. We tested the hypothesis that ph...
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To date, photic entrainment of the mammalian circadian system has been studied by following phase shifts of overt rhythms in the periphery governed by a circadian pacemaker located in the suprachiasmatic nucleus (SCN). The present study follows for the first time photic resetting of intrinsic rhythmicity of the SCN itself. Rats maintained under either a shorter photoperiod, with 12 h of light a...
متن کاملAn intact dorsomedial hypothalamic nucleus, but not the subzona incerta or reuniens nucleus, is necessary for short-day melatonin signal-induced responses in Siberian hamsters.
Siberian hamsters provide a useful model to define mechanisms underlying obesity reversal as they naturally transition from their extreme seasonal obesity in long 'summer-like' days (LDs) to a leaner state in short 'winter-like' days (SDs). These day length changes are coded into durational melatonin (MEL) signals by the pineal gland resulting in stimulation of MEL receptors (MEL(1a)-Rs). MEL(1...
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ژورنال
عنوان ژورنال: Hormones and Behavior
سال: 2014
ISSN: 0018-506X
DOI: 10.1016/j.yhbeh.2014.01.002