TY - JOUR

T1 - Local facilitation of plateau potentials in dendrites of turtle motoneurones by synaptic activation of metabotropic receptors

AU - Delgado-Lezama, Rodolfo

AU - Perrier, Jean François

AU - Hounsgaard, Jørn

PY - 1999/2/15

Y1 - 1999/2/15

N2 - 1. The spatial distribution of synaptic facilitation of plateau potentials in dendrites of motoneurones was investigated in transverse sections of the spinal cord of the turtle using differential polarization by applied electric fields. 2. The excitability of motoneurones in response to depolarizing current pulses was increased following brief activation of either the dorsolateral funiculus (DLF) or the medial funiculus (MF) even when synaptic potentials were eliminated by antagonists of ionotropic receptors. 3. The medial and lateral compartments of motoneurones were differentially polarized by the electric field generated by passing current between two electrodes on either side of the preparation. In one direction of the field lateral dendrites were depolarized while the cell body and medial dendrites were hyperpolarized (S- configuration). With current in the opposite direction the cell body and medial dendrites were depolarized while lateral dendrites were hyperpolarized (S+ configuration). 4. Following brief activation of the DLF the excitability and the generation of plateau potentials were facilitated during differential depolarization of the lateral dendrites but not during differential depolarization of the cell body and medial dendrites. Following brief activation of the MF the excitability and generation of plateau potentials were facilitated during differential depolarization of the cell body and medial dendrites but not during differential depolarization of the lateral dendrites. 5. It is concluded that the synaptic facilitation of the dihyrdropyridine-sensitive response to depolarization is compartmentalized in turtle motoneurones.

AB - 1. The spatial distribution of synaptic facilitation of plateau potentials in dendrites of motoneurones was investigated in transverse sections of the spinal cord of the turtle using differential polarization by applied electric fields. 2. The excitability of motoneurones in response to depolarizing current pulses was increased following brief activation of either the dorsolateral funiculus (DLF) or the medial funiculus (MF) even when synaptic potentials were eliminated by antagonists of ionotropic receptors. 3. The medial and lateral compartments of motoneurones were differentially polarized by the electric field generated by passing current between two electrodes on either side of the preparation. In one direction of the field lateral dendrites were depolarized while the cell body and medial dendrites were hyperpolarized (S- configuration). With current in the opposite direction the cell body and medial dendrites were depolarized while lateral dendrites were hyperpolarized (S+ configuration). 4. Following brief activation of the DLF the excitability and the generation of plateau potentials were facilitated during differential depolarization of the lateral dendrites but not during differential depolarization of the cell body and medial dendrites. Following brief activation of the MF the excitability and generation of plateau potentials were facilitated during differential depolarization of the cell body and medial dendrites but not during differential depolarization of the lateral dendrites. 5. It is concluded that the synaptic facilitation of the dihyrdropyridine-sensitive response to depolarization is compartmentalized in turtle motoneurones.

UR - http://www.scopus.com/inward/record.url?scp=0033557763&partnerID=8YFLogxK

U2 - 10.1111/j.1469-7793.1999.203ad.x

DO - 10.1111/j.1469-7793.1999.203ad.x

M3 - Journal article

C2 - 9925889

AN - SCOPUS:0033557763

VL - 515

SP - 203

EP - 207

JO - The Journal of Physiology

JF - The Journal of Physiology

SN - 0022-3751

IS - 1

ER -