Alcantara S, Soriano E, Ferrer I
Unidad de Neuropatologia, Servico de Anatomía Patológica, Universidadde Barcelona, 'Principes de España' Hospital, Feixa Llarga s/n, Hospitalet de Llobregat, Barcelona 08907, Spain.
Eur J Neurosci. 1996 Jul;8(7):1522-34. doi: 10.1111/j.1460-9568.1996.tb01615.x.
In the adult barrel cortex of the rat the calcium-binding proteins calbindin D28k (CALB) and parvalbumin (PARV) are found in separate populations of GABAergic nonpyramidal neurons. In layers II to IV of the barrel cortex most PARV-immunoreactive neurons are likely to derive from a subpopulation of CALB-immunoreactive neurons whose CALB immunoreactivity ceases when they begin to express PARV between the second and third postnatal weeks. The aim of this study was to investigate the influence of subcortical afferents on the neurochemical differentiation of cortical PARV- and CALB-immunoreactive nonpyramidal neurons during development of the barrel cortex. We produced unilateral excitotoxic lesions with a single injection of ibotenic acid (0.5 microl, 0.05 M) in different subcortical nuclei in 7- to 8-day-old rats. Lesions involving the ventroposterior thalamic nuclei resulted in delayed development of PARV and CALB immunoreactivity in the barrel cortex. One week after ibotenic acid injections a transient decrease in the number of PARV-immunoreactive neurons in layer IV was observed, together with increased numbers of CALB-immunoreactive neurons in all cortical layers. The number of nonpyramidal neurons displaying coexistence of PARV and CALB in the lesioned hemisphere also increased compared with the numbers in the control hemisphere or control littermates. In contrast, lesions affecting the globus pallidus, zona incerta and reticular thalamic nucleus transiently increased the number of PARV-immunoreactive neurons in layers II and III, but had no effect on the number of CALB-positive cells. From 3 weeks onwards no differences were found between control and lesioned hemispheres after injections into either the ventroposterior thalamic nuclei or the magnocellular basal forebrain. These results suggest that CALB and PARV expression in nonpyramidal cortical neurons can be reversibly modulated in opposite directions by different cortical afferents during postnatal development.
在成年大鼠的桶状皮质中，钙结合蛋白钙结合蛋白D28k（CALB）和小白蛋白（PARV）存在于不同的γ-氨基丁酸能非锥体神经元群体中。在桶状皮质的II至IV层中，大多数PARV免疫反应性神经元可能源自CALB免疫反应性神经元的一个亚群，当它们在出生后第二和第三周开始表达PARV时，其CALB免疫反应性就会消失。本研究的目的是调查在桶状皮质发育过程中，皮质下传入神经对皮质PARV和CALB免疫反应性非锥体神经元神经化学分化的影响。我们在7至8日龄大鼠的不同皮质下核团中单次注射鹅膏蕈氨酸（0.5微升，0.05 M），制造单侧兴奋性毒性损伤。涉及腹后丘脑核的损伤导致桶状皮质中PARV和CALB免疫反应性的发育延迟。在注射鹅膏蕈氨酸一周后，观察到IV层中PARV免疫反应性神经元数量短暂减少，同时所有皮质层中CALB免疫反应性神经元数量增加。与对照半球或对照同窝仔相比，损伤半球中显示PARV和CALB共存的非锥体神经元数量也增加了。相比之下，影响苍白球、未定带和丘脑网状核的损伤会短暂增加II和III层中PARV免疫反应性神经元的数量，但对CALB阳性细胞的数量没有影响。从3周起，在向腹后丘脑核或大细胞基底前脑注射后，对照半球和损伤半球之间未发现差异。这些结果表明，在出生后发育过程中，不同的皮质传入神经可以以相反的方向可逆地调节皮质非锥体神经元中CALB和PARV的表达。
