Effects of a 5-HT2 receptor agonist, DOI (2,5-dimethoxy-4-iodoamphetamine), and antagonist, ketanserin, on the performance of rats on a free-operant timing schedule
Effects of a 5-HT2 receptor agonist, DOI (2,5-dimethoxy-4-iodoamphetamine), and antagonist, ketanserin, on the performance of rats on a free-operant timing schedule
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DOI：
10.1097/00008877-200312000-00004
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发表时间：
2003-12-01
影响因子：
1.6
通讯作者：
Szabadi, E
中科院分区：
文献类型：
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作者：
Body, S;Kheramin, S;Szabadi, E
本实验检测了5-HT2受体激动剂DOI（2,5-二甲氧基-4-碘安非他明）和拮抗剂酮色林对时间分化性能的影响。采用自由操作的心理物理程序训练12只大鼠按下两个杠杆（A和B），在50-s试验中，间歇性地提供0.6 mol/I的蔗糖强化，使其在前半段对A产生反应，在后半段对B产生反应。心理测量曲线来源于对B的反应百分比（%B），记录在连续的5-s试验时期；对这些数据拟合logistic函数，推导出时序指标（T-50 [%B=50%对应的时间]，epsilon [logistic曲线的斜率]，Weber分数）。用连续5-s的累计切换概率估计平均切换时间S-50。DOI（0.0625、0.125和0.25 mg/kg, s.c）呈剂量依赖性降低T-50和S-50。酮色林（1.0 mg/kg）可拮抗DOI （0.25 mg/kg）的上述作用。结果表明，DOI改变了自由操作心理物理过程中的时间分化。酮色林的拮抗作用表明DOI的作用可能是由5-HT2A而不是5-HT2C受体介导的，因为酮色林对5-HT2A受体具有相对的选择性。将这些结果与我们之前使用5-HT1A受体激动剂的研究结果进行比较，表明5-HT1A和5-HT2A受体介导的时间分化在质量上相似。
This experiment examined the effect of a 5-HT2 receptor agonist DOI (2,5-dimethoxy-4-iodoamphetamine), and antagonist, ketanserin, on temporal differentiation performance. Twelve rats were trained under the free-operant psychophysical procedure to press two levers (A and B) in 50-s trials in which sucrose reinforcement (0.6 mol/I, 50 mul) was provided intermittently for responding on A during the first half, and on B during the second half of the trial. Psychometric curves were derived from percent responding on B (%B), recorded in successive 5-s epochs of the trials; logistic functions were fitted to these data for the derivation of timing indices (T-50 [time corresponding to %B=50%], epsilon [slope of the logistic curve], Weber fraction). Cumulative probability of switching in successive 5-s epochs was used to estimate the mean switching time, S-50. DOI (0.0625, 0.125 and 0.25 mg/kg, s.c.) dose-dependently reduced T-50 and S-50. These effects of DOI (0.25 mg/kg) were antagonized by ketanserin (1.0 mg/kg). The results show that DOI alters temporal differentiation in the free-operant psychophysical procedure. The antagonistic effect of ketanserin indicates that the effect of DOI was probably mediated by 5-HT2A rather than 5-HT2C receptors, since ketanserin is relatively selective for 5-HT2A receptors. Comparison of these results with our previous findings with a 5-HT1A receptor agonist indicates that 5-HT1A and 5-HT2A receptors mediate qualitatively similar effects on temporal differentiation.