Stanford John A, Osterhaus Gregory L, Vorontsova Elena, Fowler Stephen C
Department of Molecular and Integrative Physiology, University of Kansas Medical Center, University of Kansas, Kansas City, KS 66160, USA.
Behav Pharmacol. 2006 Dec;17(8):725-30. doi: 10.1097/FBP.0b013e32801155e8.
The purpose of this study was to measure forelimb force control and movement kinetics in rats, as they are affected by normal aging and the benzodiazepine lorazepam. Young (6 months), middle-aged (18 months), and aged (24 months) rats were trained to emit discrete forelimb responses on an isometric force disk within a 20-25 g force band for water reinforcement. Dependent variables included number of responses, percentage of reinforced responses, peak response forces, and inter-response times. Inter-response times were divided into two categories: inter-response times <0.5 s (reflecting rapid, discrete forelimb responses) and inter-response times 4-8 s (reflecting movement sequences). Aged rats exhibited no apparent deficits in forelimb force control. Although older rats emitted fewer responses than younger rats, their response accuracy was greater. Peak forces did not differ among the groups. Both categories of inter-response times were slower in the aged group, reflecting slowed discrete movements and movement sequencing. Lorazepam increased the number of responses and peak forces, decreased response accuracy, and lengthened inter-response times within the 4-8 s range (but not the <0.5 s range) in all age groups. The results suggest that movement sequences may be more sensitive to the effects of acute benzodiazepines than rapid discrete movements.
本研究的目的是测量大鼠的前肢力量控制和运动动力学，因为它们会受到正常衰老和苯二氮䓬类药物劳拉西泮的影响。将年轻（6个月）、中年（18个月）和老年（24个月）的大鼠训练在等距力盘上发出离散的前肢反应，在20 - 25克力的范围内以获取水作为强化物。因变量包括反应次数、强化反应的百分比、峰值反应力和反应间隔时间。反应间隔时间分为两类：反应间隔时间<0.5秒（反映快速、离散的前肢反应）和反应间隔时间4 - 8秒（反映运动序列）。老年大鼠在前肢力量控制方面没有明显缺陷。虽然老年大鼠发出的反应比年轻大鼠少，但其反应准确性更高。各组之间的峰值力没有差异。老年组的两类反应间隔时间都较慢，这反映出离散运动和运动序列都变慢。劳拉西泮增加了所有年龄组的反应次数和峰值力，降低了反应准确性，并延长了4 - 8秒范围内（但不是<0.5秒范围内）的反应间隔时间。结果表明，运动序列可能比快速离散运动对急性苯二氮䓬类药物的影响更敏感。
