Represa A, Dessi F, Beaudoin M, Ben-Ari Y
INSERM U29, Paris, France.
Neuroscience. 1991;42(1):137-50. doi: 10.1016/0306-4522(91)90154-g.
The axons of dentate granule cells, the mossy fibres, establish synaptic contacts with the thorny excrescences of the apical dendrite of CA3 pyramidal neurons. Dentate granule granule cells develop postnatally in rats, whereas the CA3 pyramidal cells are generated before birth. In the present studies, using unilateral neonatal gamma-ray irradiation to destroy the granule cells in one hemisphere, we have studied the effect of mossy fibre deprivation on the development of their targets. We show that such "degranulation" prevents the normal development of giant thorny excrescences, suggesting that the development of thorny excrescences in CA3 pyramidal neurons is under the control of mossy fibres. In contrast, irradiation of the hippocampus of the neonatal rat does not affect the development of the dendritic arborization of CA3 pyramidal cells and their non-mossy dendritic spines.
齿状颗粒细胞的轴突，即苔藓纤维，与CA3锥体神经元顶树突的棘状突起建立突触联系。齿状颗粒细胞在大鼠出生后发育，而CA3锥体细胞在出生前就已产生。在本研究中，我们使用单侧新生儿γ射线照射破坏一侧半球的颗粒细胞，研究了苔藓纤维剥夺对其靶标发育的影响。我们发现，这种“去颗粒化”会阻止巨大棘状突起的正常发育，这表明CA3锥体神经元中棘状突起的发育受苔藓纤维的控制。相比之下，新生大鼠海马体的照射并不影响CA3锥体细胞树突分支及其非苔藓树突棘的发育。
