Potier B, Krzywkowski P, Lamour Y, Dutar P
Laboratoire de Physiopharmacologie du Système Nerveux, Inserm U 161, Paris, France.
Brain Res. 1994 Oct 24;661(1-2):181-8. doi: 10.1016/0006-8993(94)91195-9.
Alterations in hippocampal circuitry may underly age-related learning and memory impairment. We showed in a previous study that the GABAB-mediated slow inhibitory postsynaptic potential (IPSP) induced in CA1 pyramidal neurons by electrical stimulation of stratum radiatum, is depressed in the hippocampus of the aged rat. This could be due to alterations in GABAergic interneuron functions. We report in this study that the number of hippocampal calbindin-immunoreactive (CaBP-IR) GABAergic interneurons is decreased in the aged rat. The mean number of CaBP-IR interneurons per slice decreases by 50% in the aged rat. The most severe loss was observed in the stratum radiatum of CA1 (78%), with a less consistent loss of immunoreactivity in CA3 (35%). In contrast, the mean number of interneurons containing parvalbumin (PV), was not significantly decreased in the aged rat. Our results show a loss of CaBP immunoreactivity in a population of GABAergic interneurons, which might be related to an altered function of these interneurons and consequently of GABAergic synaptic transmission in the aged rat. In contrast, PV immunoreactivity in interneurons located close to the pyramidal layer does not decrease in the hippocampus of the aged rat.
海马回路的改变可能是与年龄相关的学习和记忆障碍的基础。我们在先前的一项研究中表明，通过电刺激辐射层在CA1锥体神经元中诱导的GABAB介导的慢抑制性突触后电位（IPSP）在老年大鼠的海马中受到抑制。这可能是由于GABA能中间神经元功能的改变。我们在本研究中报告，老年大鼠海马中钙结合蛋白免疫反应性（CaBP-IR）GABA能中间神经元的数量减少。老年大鼠每片切片中CaBP-IR中间神经元的平均数量减少了50%。在CA1的辐射层观察到最严重的损失（78%），CA3中的免疫反应性损失不太一致（35%）。相比之下，老年大鼠中含有小白蛋白（PV）的中间神经元的平均数量没有显著减少。我们的结果表明，一群GABA能中间神经元中CaBP免疫反应性丧失，这可能与这些中间神经元功能改变有关，进而与老年大鼠GABA能突触传递改变有关。相比之下，老年大鼠海马中位于锥体层附近的中间神经元中的PV免疫反应性没有降低。
