5-HT2 receptors promote plateau potentials in turtle spinal motoneurons by facilitating an L-type calcium current
Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
The effects of serotonin (5-HT) on intrinsic properties of spinal motoneurons were investigated with intracellular recordings in a slice preparation from adult turtles. In 55% of the cells that were recorded, addition of 5-HT to the extracellular medium promoted plateau potentials as revealed by the response to depolarizing current pulses applied through the intracellular electrode. In the remaining 45% of cells, 5-HT had an inhibitory effect. However, when tested with an applied electric field that preferentially polarizes distal dendrites, 5-HT facilitated plateau potentials in 100% of the cells. Plateau potentials were also promoted by 5-HT focally applied on a dendrite by iontophoresis. Applied near the soma, 5-HT either promoted plateau potentials or inhibited spike generation. The latter effect was accompanied by a decrease in input resistance. Voltage-clamp recordings showed that the facilitation of plateau potentials mediated by L-type Ca2+ channels was due to activation of 5-HT2 receptors. These findings show that 5-HT regulates intrinsic properties of motoneurons in opposite ways: activation of 5-HT receptors in the soma region inhibits spike generation and plateau potentials, while activation of 5-HT2 receptors in the dendrites and the soma region promotes spiking by facilitation of plateau potentials mediated by L-type Ca2+ channels.
Originalsprog | Engelsk |
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Tidsskrift | Journal of Neurophysiology |
Vol/bind | 89 |
Udgave nummer | 2 |
Sider (fra-til) | 954-959 |
Antal sider | 6 |
ISSN | 0022-3077 |
DOI | |
Status | Udgivet - 1 feb. 2003 |
ID: 237698668