5-HT2 receptors promote plateau potentials in turtle spinal motoneurons by facilitating an L-type calcium current
Research output: Contribution to journal › Journal article › Research › peer-review
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.
Original language | English |
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Journal | Journal of Neurophysiology |
Volume | 89 |
Issue number | 2 |
Pages (from-to) | 954-959 |
Number of pages | 6 |
ISSN | 0022-3077 |
DOIs | |
Publication status | Published - 1 Feb 2003 |
ID: 237698668