Gonadal Regression Despite Light Pulses Coincident with Locomotor Activity in the Syrian Hamster1
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چکیده
منابع مشابه
Effects of bright light on age-related changes in the locomotor activity of Syrian hamsters.
Syrian hamsters display age-related changes in the expression of circadian rhythms and in responsiveness of the circadian system to photic and nonphotic stimuli. This study characterized the effects of age on the locomotor activity rhythm of middle-aged and old hamsters and evaluated the effects of strengthening the entraining light signal. Compared with young (4.5 mo) animals, middle-aged (11....
متن کاملSerotonergic mediation of constant light-potentiated nonphotic phase shifting of the circadian locomotor activity rhythm in Syrian hamsters.
Short-term (1-3 days) constant light exposure (brief LL) potentiates nonphotic phase shifting induced by sleep deprivation and serotonin (5-HT) agonist stimulation. The present assessments reveal that exposure to brief LL markedly alters the magnitude and shape of the 5-HT1A,7 receptor agonist, 8-(+)2-dipropyl-amino-8-hydroxyl-1,2,3,4-tetrahyronapthalene (8-OH-DPAT) phase-response curve, facili...
متن کاملTemperature dependence of gonadal regression in Syrian hamsters exposed to short day lengths.
We sought to determine whether ambient temperature (T(a)) affects gonadal function by altering the rate at which circadian rhythms entrain to short day lengths. Syrian hamsters were housed in cages where they received 14 h of light per day ("long days," 14L) at 22 degrees C. Hamsters were then transferred to cages to receive 10 h of light per day ("short days," 10L) and kept at 5, 22, or 28 deg...
متن کاملSerotonin increases the phase shift of the circadian locomotor activity rhythm in mice after dark pulses in constant light conditions.
Investigations on the effects of the 5-HT agonists and antagonists on the phase of the circadian locomotor activity rhythm of animals kept in constant light conditions (LL) are rare. Therefore the influence of R-(+)-OH-DPAT (5-HT1A receptors agonist) and metergoline (5-HT1/2/7 receptors antagonist) on the phase shift of the locomotor-activity rhythm alone and when combined with dark pulses in m...
متن کاملK-raj Mutation is an Early Event in Pancreatic Duct Carcinogenesis in the Syrian Golden Hamster1
K-ra.v oncogene mutation has been shown to be a frequent event in pancreatic ductal adenocarcinomas induced by the carcinogen V-nitroso-bis(2-oxopropyl)amine in the hamster. The present study exam ines the mutational status of the K-r«.v oncogene in lesions that precede the appearance of invasive ductal adenocarcinomas. Syrian golden ham sters (80-100 g) received 12 weekly doses of 15 mg/kg A'...
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ژورنال
عنوان ژورنال: Biology of Reproduction
سال: 1985
ISSN: 0006-3363,1529-7268
DOI: 10.1095/biolreprod33.1.93