Shukitt-Hale B, Stillman M J, Lieberman H R
GEO-CENTERS, INC., Newton Centre, MA 02159, USA.
Physiol Behav. 1996 Apr-May;59(4-5):867-71. doi: 10.1016/0031-9384(95)02107-8.
Exposure to hypobaric hypoxia rapidly produces decrements in learning and memory. Tyrosine, a neurotransmitter precursor, has beneficial behavioral effects when administered to animals and humans exposed to various acute stressors. To determine whether tyrosine would protect rats from the adverse effects of hypobaric hypoxia on spatial reference and working memory, it was administered to 27 male Fischer 344 rats tested in the Morris water maze. Rats were tested starting at 2 and 6 h of an 8 h exposure to a simulated altitude of 5950 m (19,500 ft) or sea level. Tyrosine or placebo was administered 1/2 h prior to each testing session (400 mg/kg, IP). Altitude exposure significantly increased working memory escape latency; treatment with tyrosine reversed this decrement. There was no effect of altitude or tyrosine on reference memory. There were also no treatment-related differences in performance when animals were tested the next day at sea level. The beneficial effects of tyrosine on working memory performance may be due to a direct effect of tyrosine on memory, alleviation of a hypoxia-induced retardation of learning, or to other central or peripheral effects of this dietary catecholamine precursor.
暴露于低压低氧环境会迅速导致学习和记忆能力下降。酪氨酸作为一种神经递质前体，在给予暴露于各种急性应激源的动物和人类时具有有益的行为效应。为了确定酪氨酸是否能保护大鼠免受低压低氧对空间参考记忆和工作记忆的不利影响，将其给予27只在莫里斯水迷宫中进行测试的雄性Fischer 344大鼠。大鼠在暴露于模拟海拔5950米（19,500英尺）或海平面8小时后的2小时和6小时开始进行测试。在每次测试前半小时给予酪氨酸或安慰剂（400毫克/千克，腹腔注射）。海拔暴露显著增加了工作记忆逃避潜伏期；酪氨酸治疗逆转了这种下降。海拔或酪氨酸对参考记忆没有影响。当动物第二天在海平面进行测试时，性能也没有与治疗相关的差异。酪氨酸对工作记忆性能的有益作用可能是由于酪氨酸对记忆的直接作用、缓解缺氧诱导的学习迟缓，或者是这种膳食儿茶酚胺前体的其他中枢或外周作用。
