PRESYNAPTIC SEROTONERGIC MODULATION OF SPONTANEOUS AND MINIATURE SYNAPTIC ACTIVITY IN THE FROG LUMBAR MOTONEURONS

• Published in: Žurnal ėvolûtsionnoj biohimii i fiziologii Vol. 52; no. 5; p. 328
• Main Authors: Kalinina, N I, Kurchavyi, G G, Zaitsev, A V, Vesselkin, N P
• Format: Journal Article
• Language: Russian
• Published: Russia (Federation) 01-09-2016
• Subjects: Animals; Miniature Postsynaptic Potentials; Motor Neurons - cytology; Motor Neurons - metabolism; Rana ridibunda; Serotonergic Neurons - cytology; Serotonergic Neurons - metabolism; Serotonin - metabolism; Spinal Cord - cytology; Spinal Cord - metabolism
• ISSN: 0044-4529

In this study we investigated the effect of 5-HT on the spontaneous and miniature synaptic activity in lumbar motoneurons from isolated frog spinal cord using intracellular recording. 5-HT increased the frequency of the spontaneous and miniature postsynaptic potentials (mPSPs). The effect of 5-HT on different subpopulations of mPSPs was multidirectional: it increased the frequency of glutamatergic excitatoty mPSP by 18 % and decreased the frequency of glycinergic inhibitory mPSP by 28 %, but had no effect on the frequency of GABAergic inhibitory mPSP. The amplitude and kinetic parameters of any subpopulation of mPSPs did not change. The data obtained show that 5-HT regulates the probability of glutamate and glycine release from presynaptic terminals ending at the frog spinal motoneurons. 5-HT shifts the ba- lance between synaptic excitation and inhibition in the spinal neural network toward excitation. Thus, 5-HT participates in control of motor output and provides its facilitation.