TY - JOUR

T1 - Dedifferentiation of intrinsic response properties of motoneurons in organotypic cultures of the spinal cord of the adult turtle

AU - Perrier, J F

AU - Noraberg, J

AU - Simon, M

AU - Hounsgaard, J

PY - 2000/7/1

Y1 - 2000/7/1

N2 - Explant cultures from the spinal cord of adult turtles were established and used to study the sensitivity of the intrinsic response properties of motoneurons to the changes in connectivity and milieu imposed by isolation in culture. Transverse sections 700 microm thick were explanted on cover slips and maintained in roller-tube cultures in medium containing serum and the growth factors brain-derived neurotrophin factor (BDNF), neurotrophin-3 (NT3), glial cell line-derived neurotrophic factor (GDNF) and ciliary neurotrophic factor (CNTF). The gross morphology of acute sections was maintained after 4 weeks in culture. Cell bodies of motoneurons remained stainable in fixed cultures with an antibody against choline acetyltransferase (ChAT) throughout the culture period. During culture, motoneurons maintained stable resting membrane potentials and were contacted by functional synapses. The ability to generate action potentials was also preserved as was delayed inward rectification and generation of calcium spikes in the presence of tetra-ethyl ammonium (TEA). In response to depolarization, however, motoneurons presented strong outward rectification, and only 41% of the cells recorded from maintained the ability to fire repetitively. By the second week in culture, a fraction of motoneurons displayed fast and slow transient outward rectification and low-threshold calcium spikes, features not seen in turtle motoneurons in acute slices. On the other hand, properties mediated by L-type Ca2+ channels disappeared during the first few days in culture. Our observations show that the phenotypical intrinsic response properties of mature spinal motoneurons are modified in explant cultures. The properties acquired resemble the properties in juvenile motoneurons in several species of terrestrial vertebrates.

AB - Explant cultures from the spinal cord of adult turtles were established and used to study the sensitivity of the intrinsic response properties of motoneurons to the changes in connectivity and milieu imposed by isolation in culture. Transverse sections 700 microm thick were explanted on cover slips and maintained in roller-tube cultures in medium containing serum and the growth factors brain-derived neurotrophin factor (BDNF), neurotrophin-3 (NT3), glial cell line-derived neurotrophic factor (GDNF) and ciliary neurotrophic factor (CNTF). The gross morphology of acute sections was maintained after 4 weeks in culture. Cell bodies of motoneurons remained stainable in fixed cultures with an antibody against choline acetyltransferase (ChAT) throughout the culture period. During culture, motoneurons maintained stable resting membrane potentials and were contacted by functional synapses. The ability to generate action potentials was also preserved as was delayed inward rectification and generation of calcium spikes in the presence of tetra-ethyl ammonium (TEA). In response to depolarization, however, motoneurons presented strong outward rectification, and only 41% of the cells recorded from maintained the ability to fire repetitively. By the second week in culture, a fraction of motoneurons displayed fast and slow transient outward rectification and low-threshold calcium spikes, features not seen in turtle motoneurons in acute slices. On the other hand, properties mediated by L-type Ca2+ channels disappeared during the first few days in culture. Our observations show that the phenotypical intrinsic response properties of mature spinal motoneurons are modified in explant cultures. The properties acquired resemble the properties in juvenile motoneurons in several species of terrestrial vertebrates.

KW - Action Potentials

KW - Age Factors

KW - Animals

KW - Brain-Derived Neurotrophic Factor

KW - Cell Differentiation

KW - Cesium

KW - Chlorides

KW - Ciliary Neurotrophic Factor

KW - Cycloleucine

KW - Electrophysiology

KW - Glial Cell Line-Derived Neurotrophic Factor

KW - Motor Neurons

KW - Nerve Growth Factors

KW - Nerve Tissue Proteins

KW - Neuroprotective Agents

KW - Neurotrophin 3

KW - Organ Culture Techniques

KW - Spinal Cord

KW - Synapses

KW - Tetraethylammonium

KW - Tetrodotoxin

KW - Turtles

M3 - Journal article

C2 - 10947818

VL - 12

SP - 2397

EP - 2404

JO - European Journal of Neuroscience

JF - European Journal of Neuroscience

SN - 0953-816X

IS - 7

ER -