Oxygen free radicals, melatonin, and aging.

The recognized peripheral and central biochemical, neuroendocrinological, behavioral, pharmacological, and clinical actions of melatonin are involved at different levels of an overall concept of the pathophysiology of aging. This conceptual approach combines the biochemistry of oxygen free radicals, the social behavior of the individual and the resulting cellular alterations. This has allowed us to propose antioxidant properties of melatonin that we have experimentally demonstrated.

Possible involvement of a gamma-hydroxybutyric acid receptor in startle disease.

Startle disease or hyperreflexia is an autosomal dominant neurological disorder, with a neonatal onset, characterized by muscular hypertonia and myoclonic jerks, exaggerated by the slightest stimulus. Low concentrations of free gamma-aminobutyric acid (GABA) have been found in the cerebrospinal fluid of two affected infants. The involvement of GABA or its receptors has been raised and the use of GABA-agonist drugs has been suggested.

Anxiolytic activity of melatonin in mice: involvement of benzodiazepine receptors.

The anxiolytic properties of melatonin are revealed by two behavioral studies. In a free exploratory situation, the holeboard test, melatonin decreased head-dip performance. In an unconditioned conflict test, the light/dark box choice situation, melatonin increased the time spent in the lit box as well as the number of transitions between the two compartments.

Antioxidant activity of melatonin in mice.

Melatonin (in gum tragacanth as solvent) was administered to mice in the dose range of 100 to 450 mg/kg intraperitoneally. It prevented the increase in plasma glucose resulting from pancreatic toxicity caused by the intravenous administration of alloxan at 40 mg/kg. This action of melatonin was significant and dose-dependent.

Carnitine action on neuromuscular disturbances in the fasting rat: potentiation by L-lysine.

L-Carnitine (oral route) significantly corrects the muscle hypocontractility and hypoexcitability induced in the rat after 5 consecutive days of fasting. This effect is interpreted on the basis of the dual role of L-carnitine as cofactor in the transport of long-chain fatty acids into the mitochondria and as a detoxifying agent of intracellular acyl-CoA. The activity of L-carnitine is increased with the concomitant administration (oral route) of an equimolar dose of L-lysine.