Effect of 8-OH-DPAT on temporal discrimination following central 5-hydroxytryptamine depletion

被引:20
作者
Body, S [1 ]
Chiang, TJ [1 ]
Mobini, S [1 ]
Ho, MY [1 ]
Bradshaw, CM [1 ]
Szabadi, E [1 ]
机构
[1] Univ Nottingham, Sch Med, Queens Med Ctr, Div Psychiat,Psychopharmacol Sect, Nottingham NG7 2UH, England
关键词
5-HT1A receptors; 8-OH-DPAT; 5,7-dihydroxytryptamine; timing; discrete-trials psychophysical procedure;
D O I
10.1016/S0091-3057(01)00674-8
中图分类号
B84 [心理学]; C [社会科学总论]; Q98 [人类学];
学科分类号
03 ; 0303 ; 030303 ; 04 ; 0402 ;
摘要
The 5-hydroxytryptamine (5-HT)(1A) receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) alters performance in discrete-trials timing schedules. 5-HT1A receptors occur both presynaptically and postsynaptically, but it is not known which receptor population mediates the effects of 8-OH-DPAT on timing, Rats received intra-raphe injections of 5,7-dihydroxytryptamine (n = 16) or sham lesions (n = 14). They were trained in a discrete-trials psychophysical procedure in which levers were presented at a predetermined time after the onset of each trial (2.5, 7.5,.., 47.5 s). A response on lever A was reinforced if lever presentation occurred < 25 s after trial onset; a response on lever B was reinforced if lever presentation occurred > 25 s after trial onset. After 70 preliminary sessions, the rats received 8-OH-DPAT (25, 50, 100, 200 mug kg(-1) sc) and saline vehicle, The percentage of responses on lever B (%B) increased as a function of time from trial onset. Under the baseline (vehicle-treatment) condition, performance did not differ between the two groups. 8-OH-DPAT did not alter the indifference point (time corresponding to %B = 50%), but dose-dependently increased the Weber fraction in both groups. Forebrain concentrations of 5-HT and 5-HIAA in the lesioned group were approximately 10% of control levels. The results suggest that the effect of 8-OH-DPAT on performance on discrete-trials timing schedules is mediated by postsynaptic 5-HT1A receptors. (C) 2002 Elsevier Science Inc. All rights reserved.
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页码:787 / 793
页数:7
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