Airhart Mark J, Lee Deborah H, Wilson Tracy D, Miller Barney E, Miller Merry N, Skalko Richard G
Department of Anatomy and Cell Biology, P.O. Box 70582, Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614-1708, USA.
Neurotoxicol Teratol. 2007 Nov-Dec;29(6):652-64. doi: 10.1016/j.ntt.2007.07.005. Epub 2007 Jul 19.
This study examines the effects of the selective serotonin reuptake inhibitor (SSRI), fluoxetine (PROZAC), on the ontogeny of spontaneous swimming activity (SSA) in developing zebrafish. The development of zebrafish motor behavior consists of four sequential locomotor patterns that develop over 1-5 days post fertilization (dpf), with the final pattern, SSA, established at 4-5 dpf. In stage specific experiments, larvae were exposed to 4.6 microM fluoxetine for 24 h periods beginning at 24 h post fertilization (hpf) and extending through 5 dpf. From 1-3 dpf, there was no effect on SSA or earlier stages of motor development, i.e., spontaneous coiling, evoked coiling and burst swimming. Fluoxetine exposure at 3 dpf for 24 h resulted in a transient decrease in SSA through 7 dpf with a complete recovery by 8 dpf. Larvae exposed to 4.6 microM fluoxetine for 24 h on 4 or 5 dpf showed a significant decrease in SSA by day 6 with no recovery through 14 dpf. Although SSA was significantly affected 24 h after fluoxetine exposure, there was little or no effect on pectoral fin movement. These results demonstrate both a stage specific and a long term effect of 4.6 microM fluoxetine exposure in 4 and 5 dpf larvae. Reverse transcriptase polymerase chain reaction (RT-PCR) was performed to determine the relative levels of a serotonin transporter protein (SERT) transcript and the serotonin 1A (5-HT(1A)) receptor transcript in developing embryos/larvae over 1-6 dpf. Both transcripts were present at 24 hpf with the relative concentration of SERT transcript showing no change over the developmental time range. The relative concentration of the 5-HT(1A) receptor transcript, however, showed a two-tiered pattern of concentration. RT-PCR was also used to detect potential changes in the SERT and 5-HT(1A) receptor transcripts in 6 dpf larvae after a 24 h exposure to 4.6 microM fluoxetine on 5 dpf. Three separate regions of the CNS were individually analyzed, two defined brain regions and spinal cord. The two brain regions showed no effect on transcript levels subsequent to fluoxetine exposure, however, the spinal cord showed a significant decrease in both transcripts. These results suggest a correlation between decreased concentration of SERT and 5-HT(1A) receptor transcripts in spinal cord and decreased SSA subsequent to fluoxetine exposure.
本研究考察了选择性5-羟色胺再摄取抑制剂（SSRI）氟西汀（百忧解）对斑马鱼幼体自发游泳活动（SSA）个体发育的影响。斑马鱼运动行为的发育包括在受精后1至5天（dpf）内依次出现的四种运动模式，最终模式SSA在4至5 dpf时形成。在特定阶段实验中，幼体从受精后24小时（hpf）开始至5 dpf，暴露于4.6微摩尔氟西汀中24小时。在1至3 dpf期间，对SSA或运动发育的早期阶段，即自发卷曲、诱发卷曲和爆发式游泳没有影响。在3 dpf时暴露于氟西汀24小时导致SSA在7 dpf前短暂下降，并在8 dpf时完全恢复。在4或5 dpf时暴露于4.6微摩尔氟西汀24小时的幼体在第6天时SSA显著下降，至14 dpf时未恢复。尽管在氟西汀暴露24小时后SSA受到显著影响，但对胸鳍运动几乎没有影响。这些结果表明，4.6微摩尔氟西汀暴露对4和5 dpf幼体具有阶段特异性和长期影响。进行逆转录聚合酶链反应（RT-PCR）以确定在1至6 dpf发育中的胚胎/幼体中5-羟色胺转运蛋白（SERT）转录本和5-羟色胺1A（5-HT(1A)）受体转录本的相对水平。两种转录本在24 hpf时均存在，SERT转录本的相对浓度在发育时间范围内没有变化。然而，5-HT(1A)受体转录本的相对浓度呈现出两层浓度模式。RT-PCR还用于检测在5 dpf时暴露于4.6微摩尔氟西汀24小时后6 dpf幼体中SERT和5-HT(1A)受体转录本的潜在变化。对中枢神经系统的三个不同区域分别进行分析，两个明确的脑区和脊髓。两个脑区在氟西汀暴露后转录本水平没有受到影响，然而，脊髓中两种转录本均显著下降。这些结果表明，脊髓中SERT和5-HT(1A)受体转录本浓度的降低与氟西汀暴露后SSA的降低之间存在相关性。
