Participation Of Serotonergic System Research Articles

Serotonergic Mechanisms in Locomotor Effects of Electrical Spinal Cord Stimulation

Electrical stimulation of the spinal cord (ESSC) is a method enabling researchers to confirm the existence of the stepping movement generator in humans. Currently, the ESSC-based technologies of motor rehabilitation of patients immobilized after spinal cord injury are actively developing. The impact of the serotonergic system in the organization of movement is intensively studied both at the systemic and the molecular–cellular level in a large number of researches. The aim of this review was to analyze the current experimental data on the participation of serotonergic system in the locomotor activity control at the spinal level with a focus on the processes related to electrical stimulation of spinal locomotor networks. Special interest is given to the serotonin-based regulation of human motor activity. The data on the use of serotonin-modulating pharmacotherapy for increasing the efficacy of the ESSC method in locomotor rehabilitation are presented in the final part of the review.

Evidence indicating participation of the serotonergic system in controlling feeding behavior in Coturnix japonica (Galliformes: Aves)

We investigated participation of the brain serotonergic system in food intake control by using oral and systemic administration of serotonin precursors in quails (Coturnix japonica). Dietary supplemental tryptophan (0.1-50.0 g/kg) provoked a dose-dependent inhibition of food intake during a 5-h observation period, which persisted up to 24 h for doses of 30.0 and 50.0 g/kg. Normally fed and fasted animals treated with hydroxytryptophan (12.5-50.0 mg/kg) by the intracoelomic route showed an acute inhibition of food intake. Hypophagia in fasted birds was only effective when the precursor was administered immediately before food presentation. A similar response was obtained by administering serotonin (0.125-2.5 mg/kg, sc), with animals showing a hypnogenic response within the first ten minutes after administration, suggesting that, in contrast to mammals, the amine crosses the blood-brain barrier in quails. Administration of hydroxytryptophan at all doses tested induced significant dipsogenic behavior despite the concomitant hypnogenic response. The results suggest the involvement of serotonergic pathways in food intake control in quails and also show, for the first time, hypnogenic action induced by serotonin and a hyperdipsic effect elicited by hydroxytryptophan.