Synapse elimination in the corticospinal projection during the early postnatal period

被引:20
作者
Kamiyama, T [1 ]
Yoshioka, N [1 ]
Sakurai, M [1 ]
机构
[1] Teikyo Univ, Sch Med, Dept Physiol, Itabashi Ku, Tokyo 1738605, Japan
关键词
D O I
10.1152/jn.00295.2005
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
In corticospinal synapses reconstructed in vitro by slice co-culture, we previously showed that the synapses were distributed across the gray matter at 6 - 7 days in vitro (DIV). Thereafter, they began to be eliminated from the ventral side, and dorsal- dominant distribution was nearly complete at 11 - 12 DIV. The synapse elimination is associated with retraction of the corticospinal ( CS) terminals. We studied whether this specific type of synapse elimination is a physiological phenomenon rather than in vitro artifact. The rat corticospinal tract was stimulated at the medullary pyramid, and field potentials were recorded at the cervical cord along an 200-mu m interval lattice on the axial plane. Clearly defined negative field potential were identified as field excitatory postsynaptic potentials (fEPSPs) generated by corticospinal synapses. They were recorded from the entire spinal gray matter at postnatal day 7 (P7). These negative fEPSPs reversed to positive in the most ventrolateral part at P8. Reversal extended to the more mediodorsal area at P10, indicative of progressive synapse elimination in the ventrolateral area. To verify that regression of the axons in vivo paralleled the changes in spatial distribution of fEPSPs as observed in vitro, corticospinal axons were anterogradely labeled. Redistribution of the labeled terminals closely paralleled the fEPSP distribution, being present in the ventrolateral spinal cord at P7, decreased at P8, further deceased at P10, but unchanged at P11. Furthermore, double immunostaining for labeled terminals and synaptophysin observed under a confocal microscope suggests that corticospinal fibers at P7 possess presynaptic structures in the ventrolateral area as well as the dorsomedial area. These findings suggest that corticospinal synapses are widely formed in the spinal gray matter at P7, are rapidly eliminated from the ventrolateral side from P8 to P10, a time- course very similar to that observed in vitro, and are associated with axonal regression.
引用
收藏
页码:2304 / 2313
页数:10
相关论文
共 58 条
[31]  
Li SX, 2003, J NEUROSCI, V23, P4219
[32]   Development of the vertebrate main olfactory system [J].
Lin, DM ;
Ngai, J .
CURRENT OPINION IN NEUROBIOLOGY, 1999, 9 (01) :74-78
[33]   AN INVESTIGATION OF PYRAMIDAL TRACT CELLS IN SOMATOSENSORY CORTEX OF RAT [J].
MCCOMAS, AJ ;
WILSON, P .
JOURNAL OF PHYSIOLOGY-LONDON, 1968, 194 (01) :271-&
[34]   CONDUCTION VELOCITIES OF CORTICOSPINAL AXONS IN THE RAT STUDIED BY RECORDING CORTICAL ANTIDROMIC RESPONSES [J].
MEDIRATTA, NK ;
NICOLL, JAR .
JOURNAL OF PHYSIOLOGY-LONDON, 1983, 336 (MAR) :545-561
[35]   The transition from development to motor control function in the corticospinal system [J].
Meng, Z ;
Li, Q ;
Martin, JH .
JOURNAL OF NEUROSCIENCE, 2004, 24 (03) :605-614
[36]   Postnatal development of corticospinal postsynaptic action [J].
Meng, Z ;
Martin, JH .
JOURNAL OF NEUROPHYSIOLOGY, 2003, 90 (02) :683-692
[37]   Differential induction of LTP and LTD is not determined solely by instantaneous calcium concentration: an essential involvement of a temporal factor [J].
Mizuno, T ;
Kanazawa, I ;
Sakurai, M .
EUROPEAN JOURNAL OF NEUROSCIENCE, 2001, 14 (04) :701-708
[38]   THE ORGANIZATION OF THE RAT MOTOR CORTEX - A MICROSTIMULATION MAPPING STUDY [J].
NEAFSEY, EJ ;
BOLD, EL ;
HAAS, G ;
HURLEYGIUS, KM ;
QUIRK, G ;
SIEVERT, CF ;
TERREBERRY, RR .
BRAIN RESEARCH REVIEWS, 1986, 11 (01) :77-96
[39]   Critical period for activity-dependent elimination of corticospinal synapses in vitro [J].
Ohno, T ;
Sakurai, M .
NEUROSCIENCE, 2005, 132 (04) :917-922
[40]   Regionally specific distribution of corticospinal synapses because of activity-dependent synapse elimination in vitro [J].
Ohno, T ;
Maeda, H ;
Sakurai, M .
JOURNAL OF NEUROSCIENCE, 2004, 24 (06) :1377-1384