[How can we help a binge eater?].

In primary health care, early recognition of a patient having a binge eating disorder is essential already before the development of overweight. The therapy aims at gaining control over eating, stopping radical attempts at weight reduction and guiding the binge eater to follow a regular meal rhythm and a well-balanced diet. With the help of a regular meal rhythm, food volumes in binge-eating episodes will decrease fairly quickly and the episodes become less frequent.

Circadian phenotype in patients with the co-morbid alcohol use and bipolar disorders.

Aims: Alcohol misuse is associated with bipolar disorder. Abnormalities in the circadian clockwork play a role in the pathogenesis of bipolar disorder. Alcohol intake is likely to affect the circadian phenotype.

Evidence for central alpha(2)-adrenergic modulation of rat pineal melatonin synthesis.

This study was performed to distinguish central and peripheral alpha(2)-adrenoceptors in the inhibition of rat pineal melatonin synthesis. The rats received lipo- or hydrophilic alpha(2)-adrenoceptor ligand injections at middark; after 1 or 2 h the pineal melatonin contents were measured. The lipophilic agonist medetomidine (100 microg/kg s.

Bright light exposure of a large skin area does not affect melatonin or bilirubin levels in humans.

Background: Light treatment through the eyes is effective in alleviating the symptoms of some psychiatric disorders. A recent report suggested that skin light exposure can affect human circadian rhythms. Bilirubin can serve as a hypothetical blood-borne mediator of skin illumination into the brain.

Supersensitivity with reduced capacity for pineal melatonin synthesis in constant light-treated rats.

Melatonin is synthetized from serotonin in two steps driven by the enzymes N-acetyltransferase and hydroxyindole-O-methyltransferase. Constant light treatment reduces rat pineal hydroxyindole-O-methyltransferase activity while the activation of N-acetyltransferase becomes supersensitive to adrenergic stimulation. We studied the effect of this discrepancy on the production of melatonin.

No evidence for extraocular light induced phase shifting of human melatonin, cortisol and thyrotropin rhythms.

The view that light affects the mammalian circadian clock only through the eyes was recently challenged by a study in which the phases of human circadian rhythms were shifted by extraocular light exposure. This finding has not been confirmed, however. We studied the effects of light exposure (3 h, broad spectrum fluorescent white light, 13000 lux) on abdomen and chest on the circadian rhythms of serum melatonin, cortisol and thyrotropin in six subjects.

Suppression of melatonin by 2000-lux light in humans with closed eyelids.

Background: In order to clarify the role of light in regulating body functions in sleeping humans, we studied whether the light-sensitive pineal hormone melatonin can be suppressed by facial light exposure in subjects with closed eyelids.

Methods: Eight healthy volunteers participated in 3 nightly sessions: a dim-light control session (< 10 lux) and two light-exposure sessions (2000 lux, 60 min between 2400 and 0200 h). One light exposure occurred with eyes open and the other with eyes closed.

Evidence against alpha2-adrenoceptor involvement in the regulation of rat melatonin synthesis by ambient lighting.

This study was carried out to clarify the role of alpha2-adrenoceptors in the regulation of pineal melatonin synthesis. Medetomidine, a selective alpha2-adrenoceptor agonist, was previously found to be a potent suppressor of nocturnal melatonin levels in rats. Medetomidine and alpha2-adrenoceptor antagonists atipamezole and yohimbine were injected into rats in different conditions, and their pineal melatonin contents were measured by radioimmunoassay.

Melatonin ineffective in neuronal ceroid lipofuscinosis patients with fragmented or normal motor activity rhythms recorded by wrist actigraphy.

Melatonin was tested as a sleeping pill in five patients with neuronal ceroid lipofuscinoses. The single-blind, placebo-controlled study consisted of motor activity recordings, sleep logs, and administration of placebo or melatonin (2.5 or 5 mg).

Bright light suppresses melatonin in blind patients with neuronal ceroid-lipofuscinoses.

We studied whether light information can reach the pineal glands of clinically blind patients with neuronal ceroid-lipofuscinoses. The suppression of melatonin by light was used as an indicator. Seven patients and seven control subjects were exposed to 3,000-lux light for 60 minutes at the rising phase of the melatonin synthesis.

Alpha2-adrenoceptor agonist medetomidine affects the melatonin rhythm in rats.

We investigated whether alpha2-adrenergic mechanisms participate in the regulation of the daily melatonin rhythm. Female Wistar rats, living under 12:12 h light-dark conditions, received a subcutaneous injection of saline or medetomidine (alpha2-adrenoceptor agonist; 100 microg/kg) 1 h after lights off. Thereafter they were kept in continuous darkness.

Pineal melatonin in rats: suppression by the selective alpha2-adrenoceptor agonist medetomidine.

This study was done to clarify the role of alpha2-adrenoceptors in the regulation of pineal melatonin synthesis. A selective alpha2-adrenoceptor agonist, medetomidine, and antagonist, atipamezole, were injected subcutaneously into rats and their pineal melatonin contents were measured by radioimmunoassay. Medetomidine (120 microg/kg) suppressed melatonin at night to a similar extent during the rising and descending phase of melatonin synthesis, but it did not affect the daytime level.

Ontogeny of pineal melatonin rhythm in rats under 12:12-hr and 14:14-hr light:dark conditions.

The aim of the study was to determine whether a discrepancy between the genetically determined endogenous circadian period and an abnormally long Zeitgeber period disturbs the development of melatonin synthesis. Breeding pairs of rats were kept under 12:12- or 14:14-hr light:dark (LD) conditions. Pineal melatonin contents in the offspring were measured by radioimmunoassay.

Exogenous melatonin fails to counteract the light-induced phase delay of human melatonin rhythm.

Salivary melatonin levels were measured in 6 healthy volunteers in order to determine whether the phase shift caused by a single 60-min light pulse of 2000 lux might be inhibited by maintaining high melatonin concentration. In the control sessions, the samples were collected at 60-min intervals under lighting of < 10 lux from 18.00 to 11.

Daytime dark exposure increases pineal melatonin in rat pups.

Photic regulation of the pineal melatonin synthesis was studied in 3- to 21-day-old rat pups by exposing the animals to light at night (30-40 min) or to darkness during the day (30-240 min). The pineal melatonin contents were measured by radioimmunoassay. A significant day/night difference in the melatonin content and the nocturnal light-induced decrease were not found until second postnatal week.

Circadian rhythm studies in neuronal ceroid-lipofuscinosis (NCL).

Sleep disorders are common in NCL patients. The patients have problems such as frequent awakenings, difficulties with sleep onset, nightmares, and night terrors. The aim of the study was to examine whether the sleep disturbance in NCL can be explained on the basis of desynchronised circadian rhythms.

Uncoupling of the pineal melatonin synthesis of rats from the circadian regulation.

We show that the pineal melatonin synthesis of rats can be uncoupled from the circadian regulation by exposing the animals to abnormally long light periods. Male rats were kept 7 days under 22.5/1.

The adjustment of the melatonin rhythm of rats by 90-min dark pulses.

The pineal melatonin patterns were measured in rats kept 1, 2, 3, 4, 6, 8, 16, or 28 days under the lighting conditions with a dark period of 90 min only (from 18:00 to 19:30 h). The samples were collected at 30-min intervals, and melatonin was measured by radioimmunoassay. During the first and second dark pulse the melatonin levels were low, but thereafter they were significantly higher than the usual daytime levels.

One-hour exposure to moderate illuminance (500 lux) shifts the human melatonin rhythm.

Salivary melatonin levels were measured in 12 healthy volunteers in order to determine whether a moderate light intensity, which suppresses the nocturnal rise of melatonin, was able to shift the melatonin rhythm. The samples were collected at 1-hr intervals under lighting of < 100 lux (experiment 1) or < 10 lux (experiment 2). The control melatonin profiles were determined during the first night.

Melatonin, cortisol and body temperature rhythms in Lennox-Gastaut patients with or without circadian rhythm sleep disorders.

The daily rhythms of melatonin, cortisol and body temperature were studied in 16 institutionalized subjects with the Lennox-Gastaut syndrome. The results of 9 subjects with normal daily rhythms of sleep and wakefulness (group 1) were compared with those of 7 subjects with disordered sleep (group 2). Salivary samples were collected and axillary temperature was measured every 2 h during two or three separate 26-h periods.