Search results for "circadian rhythm"
showing 10 items of 324 documents
The role of arginine-vasopressin for pineal melatonin synthesis in the rat: involvement of vasopressinergic receptors.
1991
Abstract The endogenously synthesized nonapeptide arginine vasopressin (AVP) is thought to be involved in transduction of photic information to the pineal gland. The enhancement of circulating AVP leads to a suppression of the nocturnal melatonin surge the mechanisms of which are unknown so far. We therefore studied the effect of dDAVP, an AVP analog with antidiuretic but without vasopressor activity, on pineal melatonin synthesis in Sprague-Dawley and AVP-deficient Brattleboro rats. The nocturnal intra-arterial application of dDAVP mimicked the inhibitory effect of AVP on the activity of the rate-limiting enzyme for pineal melatonin synthesis, N-acetyltransferase (NAT), in both rat strains…
The effects of sex hormones, prolactin, and chorionic gonadotropin on pineal electrical activity in guinea pigs.
1981
Microelectrophoretic application of sex hormones onto pineal cells in guinea pigs has shown different responses in pregnant females as compared to males. In pregnant females estrone caused excitation in 74% of the cells tested, while progesterone and testosterone, prolactin, and HCG were inhibitory in a majority of the cells tested, while progesterone and testosterone, prolactin, and HCG were inhibitory in a majority of the cells. In contrast, in males estrone caused excitation of only 19% but inhibition of 37%. A smaller percentage of cells was inhibited by progesterone, while the predominant response to testosterone was excitation. These results suggest that the pineal gland may be under …
Photoreceptor cells display a daily rhythm in the orphan receptor Esrrβ
2015
Purpose Nuclear orphan receptors are critical for the development and long-term survival of photoreceptor cells. In the present study, the expression of the nuclear orphan receptor Esrrβ—a transcriptional regulator of energy metabolism that protects rod photoreceptors from dystrophy—was tested under daily regulation in the retina and photoreceptor cells. Methods The daily transcript and protein amount profiles were recorded in preparations of the whole retina and microdissected photoreceptor cells using quantitative PCR (qPCR) and western blot analysis. Results Esrrβ displayed a daily rhythm with elevated values at night in the whole retina and enriched photoreceptor cells. Daily regulation…
Day- and night-time contents of monoamines and their metabolites in the medial preoptic area of the rat hypothalamus.
1999
The present study was conducted to investigate whether monoamines and their metabolites in the medial preoptic area (mPOA) of the rat hypothalamus exhibit differences in their contents between day and night. We therefore sampled the mPOA from adult animals of either sex at the middle of the light or dark period, respectively, and analyzed the tissue by means of high performance liquid chromatography with electrochemical detection. We found that, in female animals at mid-night, dopamine and 3,4-dihydroxyphenyl acetic acid (DOPAC) was reduced to 43 and 30%, respectively, of daytime levels, while the norepinephrine content was doubled. No significant differences were observed in male animals. …
Phosphodiesterase 10A in the Rat Pineal Gland: Localization, Daily and Seasonal Regulation of Expression and Influence on Signal Transduction
2010
The cyclic nucleotide phosphodiesterase 10A (PDE10A) is highly expressed in striatal spiny projection neurons and represents a therapeutic target for the treatment of psychotic symptoms. As reported previously [J Biol Chem 2009; 284:7606–7622], in this study PDE10A was seen to be additionally expressed in the pineal gland where the levels of PDE10A transcript display daily changes. As with the transcript, the amount of PDE10A protein was found to be under daily and seasonal regulation. The observed cyclicity in the amount of PDE10A mRNA persists under constant darkness, is blocked by constant light and is modulated by the lighting regime. It therefore appears to be driven by the master cloc…
The longer the better: Sleep–wake patterns during preparation of the World Rowing Junior Championships
2016
Recovery is essential for high athletic performance, and therefore especially sleep has been identified as a crucial source for physical and psychological well-being. However, due to early-morning trainings, which are general practice in many sports, athletes are likely to experience sleep restrictions. Therefore, this study investigated the sleep-wake patterns of 55 junior national rowers (17.7 ± 0.6 years) via sleep logs and actigraphy during a four-week training camp. Recovery and stress ratings were obtained every morning with the Short Recovery and Stress Scale on a 7-point Likert-type scale ranging from 0 (does not apply at all) to 6 (fully applies). The first training session was sch…
Sleep in children with autistic spectrum disorder: a questionnaire and polysomnographic study.
2007
Abstract Objective To evaluate sleep in children with autistic spectrum disorder (ASD) by means of sleep questionnaires and polysomnography; moreover, to analyze their cyclic alternating pattern (CAP). Methods Thirty-one patients with ASD (28 males, 3 females, aged 3.7–19 years) and age-matched normal controls were included. ASD children were evaluated by a standard sleep questionnaire that consisted of 45 items in a Likert-type scale covering several areas of sleep disorders and by overnight polysomnography in the sleep laboratory after one adaptation night. Results The questionnaire results showed that parents of ASD children reported a high prevalence of disorders of initiating and maint…
Enuresis Subtypes Based on Nocturnal Hypercalciuria: A Multicenter Study
2003
Purpose: Desmopressin may not be effective for nocturnal enuresis associated with polyuria and hypercalciuria. Nighttime hypercalciuria in an enuretic population from 5 centers and its correlation with nighttime polyuria were verified. Materials and Methods: A total of 450 enuretic patients (278 males, 172 females, mean age 9.7 years) were evaluated with 72-hour micturition charts, urinalysis, serum creatinine and osmolarity, diurnal and nocturnal electrolytes with fractional Na+ and K+ urinary excretion, and nocturnal (4 a.m.) plasma vasopressin. Creatinine electrolytes and osmolarity were measured in daytime (8 a.m. to 8 p.m.) and nighttime (8 p.m. to 8 a.m.) urine volumes. Patients were …
Cortisol awakening response and cognitive performance in hypertensive and normotensive older people.
2016
Healthy older people with a cortisol awakening response (CAR) of decreased magnitude show worse frontal cortex-related cognitive performance. Systemic hypertension has been related to a CAR of decreased magnitude. Additionally, worse executive function and processing speed have been observed in older people with systemic hypertension. This is the first study to examine the relationship between the CAR (measured with six saliva samples at home on two consecutive weekdays) and cognitive performance, in both hypertensive (n=26) and normotensive (n=28) older people (from 56 to 78years old). Hypertensive participants showed lower morning cortisol secretion, and they also woke up earlier. No diff…
The effects of telmisartan alone or with hydrochlorothiazide on morning and 24-h ambulatory BP control: results from a practice-based study (SURGE 2)
2012
Observational studies have shown that 24-h and morning ambulatory blood pressure (BP) control is low. This large-scale, practice-based study evaluated the effects of telmisartan 40 or 80 mg alone or in combination with hydrochlorothiazide (HCTZ) 12.5 mg on these BP parameters over 8 weeks; treatment was adjusted if clinic BP remained ≥140/90 mm Hg. A total of 863 patients were evaluated (baseline mean clinic BP, morning and 24-h ambulatory BP: 155±15/93±10 mm Hg, 137±15/83±11 mm Hg, 133±14/79±10 mm Hg, respectively; 68% were previously treated at baseline). Telmisartan with/without HCTZ significantly reduced the mean morning ambulatory BP (-8.2/-4.9 mm Hg), daytime ambulatory BP (-8.0/-4.7 …