Liao R M, Chang Y H
Department of Psychology, National Cheng-Chi University, Taipei, Taiwan, ROC.
Proc Natl Sci Counc Repub China B. 2001 Oct;25(4):223-32.
5-hydroxytryptamine (5-HT ) is thought to be involved in a wide range of behavioral functions. Based on binding evidence, 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT), 1-(2,5-dimethoxy-4-indophenyl)-2-aminopropane (DOI), and m-chloro-phenyl-biguanide (m-CPBG) are selective 5-HT1a, 5-HT2, and 5-HT3 receptor agonists, respectively. The present study examined the effects of these 5-HT receptor agonists on operant behavior maintained on the differential reinforcement for low rate response 10-second (DRL 10-s) and 30-second (DRL 30-s) schedules of reinforcement. Water-deprived rats were trained to press a lever in response to DRL 10-s and DRL 30-s schedules. After a stable baseline was set, each subject was then repeatedly challenged using one drug with different doses through peripheral administration. The dose ranges were 0.025, 0.05, and 0.1 mg/kg (SC) for 8-OH-DPAT; 0.5, 1, and 2 mg/kg (SC) for DOI; and 1.3 and 9 mg/kg (IP) for m-CPBG. The overall results of the present work indicate that distinct profiles of operant response on DRL 10-s and DRL 30-s schedules were produced by 8-OH-DPAT, DOI, and, m-CPBG, based on quantitative and qualitative data analyses. All three 5-HT receptor agonists caused the number of responses to the DRL 10-s schedule to decrease significantly in a dose-related fashion. The operant performance on the DRL 10-s schedule was more sensitive to drug treatment than was that on the DRL 30-s schedule. Analyses of inter-response time (IRT) distributions revealed that different time bins were shifted by each of these three agents. The current data indicate that 8-OH-DPAT, DOI and m-CPBG can significantly alter operant response maintained on a DRL schedule. The distinct operant performance for each drug is believed to be derived from drug activation of its own specific 5-HT subtype receptors.
5-羟色胺（5-HT）被认为参与了广泛的行为功能。基于结合证据，8-羟基-2-（二正丙基氨基）四氢萘（8-OH-DPAT）、1-（2,5-二甲氧基-4-吲哚苯基）-2-氨基丙烷（DOI）和间氯苯基双胍（m-CPBG）分别是5-HT1a、5-HT2和5-HT3受体激动剂。本研究考察了这些5-HT受体激动剂对在低速率反应10秒（DRL 10-s）和30秒（DRL 30-s）强化程序下维持的操作性行为的影响。对水剥夺的大鼠进行训练，使其根据DRL 10-s和DRL 30-s程序按压杠杆。在设定稳定的基线后，然后通过外周给药，用一种药物的不同剂量对每个受试者进行反复挑战。8-OH-DPAT的剂量范围为0.025、0.05和0.1mg/kg（皮下注射）；DOI为0.5、1和2mg/kg（皮下注射）；m-CPBG为1.3和9mg/kg（腹腔注射）。基于定量和定性数据分析，本研究的总体结果表明，8-OH-DPAT、DOI和m-CPBG在DRL 10-s和DRL 30-s程序上产生了不同的操作性反应特征。所有三种5-HT受体激动剂均导致对DRL 10-s程序的反应次数以剂量相关的方式显著减少。DRL 10-s程序上的操作性表现比DRL 30-s程序对药物治疗更敏感。反应间隔时间（IRT）分布分析表明，这三种药物中的每一种都使不同的时间区间发生了偏移。当前数据表明，8-OH-DPAT、DOI和m-CPBG可显著改变在DRL程序下维持的操作性反应。每种药物独特的操作性表现被认为源于其自身特定5-HT亚型受体的药物激活。
