[Advances in studies of biological clock gene].

The circadian clock genes, which generate and control the running of the circadian rhythms, exist in organisms ranging from prokaryotes to mammals. The oscillator genes and its coding proteins compose the feedback loops of circadian system. The kind, number and regulating route of clock genes are characterized by living things at different evolution levels.

Influences of a light-dark profile and the pineal gland on the hypnotic activity of melatonin in mice and rats.

We have investigated the influences of the light-dark cycle and the pineal gland on the hypnotic activity of melatonin in rats and mice. The results showed that melatonin significantly shortened time to sleep onset and wakefulness time, increased slow wave sleep, paradoxical sleep, and total sleep time in rats during the light phase of a 12-h light:12-h dark cycle, by electroencephalogram recording. However, during the dark phase it had almost no significant sleep-promoting effect except shortened time to sleep onset.

[The role of melatonin receptor and GABAA receptor in the sleeping time prolonged by melatonin in mice].

Aim: To observe the role of melatonin receptor and GABAA receptor in sleeping time prolonged by melatonin in mice.

Methods: The absence of the righting reflex was considered as the sleep onset and the duration of the loss of the righting reflex was recorded as the sleeping time. The effects of receptor agonist and antagonist on hypnotic activity of melatonin were studied in the paper.

[Effect of atropine on the inhibition of melatonin to the unit discharges evoked in the posterior group of thalamic nuclei in cats].

Aim: To study the effect of atropine, muscarinic cholinergic antagonist, on the central analgesic action of melatonin (MT) and to explore the mechanism of MT analgesia.

Methods: As an indicator of visceral pain, the unit discharges of the neurons in the posterior group of thalamic nuclei (PO) were caused by stimulating the great splanchnic nerve (GSN) of the cat. The cranial stereotaxic and extracellular glass microelectrode record technique were used.

Hypnotic activity of melatonin: involvement of semicarbazide hydrochloride, blocker of synthetic enzyme for GABA.

Aim: To assess the effect of semicarbazide hydrochloride (SCZ), the blocker of synthetic enzyme for GABA, on the hypnotic activity of melatonin.

Methods: Righting reflex method in mice and electroencephalography (EEG) in rats were used to determine effects of SCZ on sleep and hypnotic activity of melatonin.

Results: Melatonin displayed a marked hypnotic activity both in righting reflex experiment and EEG recording.