Involvement of dopamine receptors in the antidepressant-like effect of melatonin in the tail suspension test.

Melatonin was previously shown to produce an antidepressant-like effect in the tail suspension test. In this work the mechanisms underlying its antidepressant-like effect were further studied by investigating the involvement of the dopaminergic system in its antidepressant-like effect in the tail suspension test. The effect of melatonin (1mg/kg, i.

GABA(A) autoreceptors enhance GABA release from human neocortex: towards a mechanism for high-frequency stimulation (HFS) in brain?

High-frequency stimulation (HFS) in human neocortical slices induces gamma-aminobutyric acid (GABA) release via GABA(A) receptor (GABA(A)R) activation. The mechanism of this effect and the localization of these GABA(A)Rs were now studied. Fresh human neocortical slices were subjected to HFS (130 Hz) in the presence of veratridine (3 microM).

Mechanisms involved in the antinociception caused by melatonin in mice.

The present study assesses the antinociceptive effect of melatonin in chemical behavioral models of nociception and investigates some of the mechanisms underlying this effect. Melatonin administered by intraperitoneal (i.p.

Modulation of catecholamine release from rat striatal slices by the fixed combination of aspirin, paracetamol and caffeine.

The fixed combination of aspirin, paracetamol (acetaminophen) and caffeine has been used successfully to treat different kinds of pain including migraine attacks. Even when this formulation has been marketed for a long time, the exact molecular mechanisms underlying its therapeutic effectiveness have not been completely elucidated. In the present investigation, we have studied the effects of the fixed combination of aspirin, paracetamol and caffeine (APC) on the release of dopamine and noradrenaline from rat striatal slices in an attempt to find potential new mechanisms of action of this widely used analgesic combination.

5-HT uptake blockade prevents the increasing effect of K(ATP) channel blockers on electrically evoked [3H]-5-HT release in rat and mouse neocortical slices.

To explore if prolonged--as opposed to acute--5-HT uptake blockade can lead to changes in the function of ATP-dependent potassium (K(ATP)) channels, we investigated in rat and mouse neocortical slices the effects of K(ATP) channel blockers on electrically evoked [3H]-serotonin ([3H]-5-HT) release after short- and long-term exposure to 5-HT uptake blockers. Glibenclamide (1 microM), a K(ATP) channel blocker, enhanced the electrically evoked [3H]-5-HT release by 66 and by 77%, respectively, in rat and in mouse neocortex slices. This effect was confirmed in the rat by tolbutamide (1 microM), another K(ATP) channel antagonist.

No modulatory effect of neurokinin-1 receptor antagonists on serotonin uptake in human and rat brain synaptosomes.

Some studies have demonstrated antidepressant activity of neurokinin-1-receptor antagonists (NK-1-RA) in major depressive disorder. However, the underlying mechanisms of this antidepressant effect are largely unknown. Preclinical studies in rats and mice have suggested that NK-1-RA do increase the neuronal release of serotonin (5-HT).

Melatonin exerts an antidepressant-like effect in the tail suspension test in mice: evidence for involvement of N-methyl-D-aspartate receptors and the L-arginine-nitric oxide pathway.

This study investigated the effect of melatonin in the mouse tail suspension test (TST), and the contribution of N-methyl-D-aspartate (NMDA) receptors and the L-arginine-nitric oxide (NO) pathway to its antidepressant-like effect. The immobility time in the TST was reduced by melatonin given either by intraperitoneal (0.1-30 mg/kg) or intracerebroventricular (0.