INTRACEREBRAL METHIONINE-ENKEPHALIN, SERUM CORTISOL, AND SERUM BETA-ENDORPHIN DURING ACUTE EXPOSURE OF SHEEP OR PHYSICAL OR ISOLATION STRESS
INTRACEREBRAL METHIONINE-ENKEPHALIN, SERUM CORTISOL, AND SERUM BETA-ENDORPHIN DURING ACUTE EXPOSURE OF SHEEP OR PHYSICAL OR ISOLATION STRESS
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DOI：
10.2527/1994.723700x
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发表时间：
1994-03-01
影响因子：
3.3
通讯作者：
MALVEN, PV
中科院分区：
文献类型：
--
作者：
HASHIZUME, T;HAGLOF, SA;MALVEN, PV
在体内微透析被用来估计细胞外浓度的甲硫氨酸脑啡肽在19个大脑网站上连续三天（试验）的每一个5小时在6个清醒的母羊。在D 1的控制程序后，在D 2（心理应激）将母羊与其他绵羊完全隔离60分钟。物理应力施加在D 3，包括连续捏的皮肤60分钟，在中间的5小时的实验期间。施加的身体和心理压力迅速增加血清皮质醇浓度，并诱导增加持续至少30分钟后终止的压力。心理压力的隔离最初增加皮质醇在更大程度上比物理压力的皮肤捏，但这种差异消失后30分钟的压力暴露。心理压力也会短暂增加血清中β-内啡肽/β-促脂素的浓度，而身体压力则不会。当将脑内探针置于尾状核、下丘脑视前区或丘脑时，透析液中甲硫氨酸脑啡肽的平均浓度范围为1.52 - 1.85 ng/mL。当将探针置于大脑的主要纤维束（胼胝体，内囊）时，甲硫氨酸脑啡肽的浓度始终低于1.0 ng/mL。位于尾状核的探针尖端周围的钾诱导去极化使甲硫氨酸脑啡肽的透析液浓度增加2.7倍。施加身体或心理压力并没有持续增加或减少透析液中蛋氨酸脑啡肽的浓度在任何研究的大脑部位。总之，压力是可靠的诱导绵羊，和细胞外浓度的蛋氨酸脑啡肽在局部脑区的微透析估计。然而，无论是心理还是身体压力都不会影响大脑中甲硫氨酸脑啡肽的浓度。
In vivo microdialysis was used to estimate extracellular concentrations of methionine-enkephalin in 19 brain sites for 5 h on each of three consecutive days (trials) in six conscious ewes. Following control procedures on d 1, ewes were completely isolated from other sheep for 60 min on d 2 (psychological stress). Physical stress was imposed on d 3 and consisted of continuous pinching of the skin for 60 min during the middle of the 5-h experimental period. Imposition of both physical and psychological stress rapidly increased serum concentrations of cortisol, and the induced increase persisted for at least 30 min after termination of the stress. Psychological stress of isolation initially increased cortisol to a greater extent than the physical stress of skin pinch, but this difference disappeared after 30 min of stress exposure. Psychological stress also transiently increased serum concentrations of beta-endorphin/beta-lipotropin, whereas physical stress did not. Average concentrations of methionine-enkephalin in dialysate ranged between 1.52 and 1.85 ng/mL when the intracerebral probes were placed into the caudate nucleus, the preoptic area of the hypothalamus, or the thalamus. The concentration of methionine-enkephalin was consistently less than 1.0 ng/mL when probes were placed into major fiber tracts of the brain (corpus callosum, internal capsule). Potassium-induced depolarization around the probe tip located in the caudate nucleus increased dialysate concentrations of methionine-enkephalin by 2.7-fold. Imposition of physical or psychological stress did not consistently increase or decrease dialysate concentrations of methionine-enkephalin in any of the brain sites studied. In summary, stress was reliably induced in sheep, and extracellular concentrations of methionine-enkephalin in local brain areas were estimated by microdialysis. However, neither psychological nor physical stress affected concentrations of methionine-enkephalin within the brain.