Bronzino J D, Abu-Hasaballah K, Austin-LaFrance R J, Morgane P J
Trinity College, Department of Engineering and Computer Science, Hartford, CT 06106.
Brain Res Bull. 1995;36(3):321-4. doi: 10.1016/0361-9230(94)00203-d.
The magnitude and duration of long-term potentiation (LTP) of perforant path/dentate granule cell synapses was examined in freely moving rats beginning at 15 days of age. Measures of dentate granule cell population EPSP slope and population spike amplitude (PSA) obtained before and after tetanization were used to evaluate the level of LTP. Tetanization resulted in significant enhancement of both the population EPSP slope (approximately +75%) and PSA (approximately +40%) measures. This enhancement was maintained without significant change for 18 h, after which both measures began a steady and continuous rise. Daily input/output response measures from age-matched nontetanized animals were used to factor out enhancement related to normal development. Under this schema, tetanization-induced enhancement of both EPSP slope and PSA measures decayed slowly, beginning 18-24 h after tetanization, returning to baseline 5 days after tetanization. Enhancement obtained from 90-day-old animals decayed to baseline 24 h after tetanization. The longer duration of LTP obtained from preweanlings is discussed with regard to the development of inhibitory systems modulating granule cell excitability.
从15日龄开始，在自由活动的大鼠中检测穿通通路/齿状颗粒细胞突触长时程增强（LTP）的幅度和持续时间。用强直刺激前后获得的齿状颗粒细胞群体兴奋性突触后电位（EPSP）斜率和群体峰电位幅度（PSA）测量值来评估LTP水平。强直刺激导致群体EPSP斜率（约+75%）和PSA（约+40%）测量值均显著增强。这种增强在18小时内保持无显著变化，之后这两个测量值开始稳步持续上升。来自年龄匹配的未强直刺激动物的每日输入/输出反应测量值用于排除与正常发育相关的增强作用。在此模式下，强直刺激诱导的EPSP斜率和PSA测量值的增强作用缓慢衰减，在强直刺激后18 - 24小时开始，在强直刺激后5天恢复到基线水平。从90日龄动物获得的增强作用在强直刺激后24小时衰减至基线水平。关于调节颗粒细胞兴奋性的抑制系统的发育，讨论了从断奶前动物获得的LTP持续时间较长的问题。
