Hapiak Vera M, Hobson Robert J, Hughes Lindsay, Smith Katherine, Harris Gareth, Condon Christina, Komuniecki Patricia, Komuniecki Richard W
Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606-3390, USA.
Genetics. 2009 Jan;181(1):153-63. doi: 10.1534/genetics.108.096891. Epub 2008 Nov 10.
Serotonin (5-HT) regulates key processes in both vertebrates and invertebrates. Previously, four 5-HT receptors that contributed to the 5-HT modulation of egg laying were identified in Caenorhabditis elegans. Therefore, to assess potential receptor interactions, we generated animals containing combinations of null alleles for each receptor, especially animals expressing only individual 5-HT receptors. 5-HT-stimulated egg laying and egg retention correlated well with different combinations of predicted excitatory and inhibitory serotonergic inputs. For example, 5-HT did not stimulate egg laying in ser-1, ser-7, or ser-7 ser-1 null animals, and ser-7 ser-1 animals retained more eggs than wild-type animals. In contrast, 5-HT-stimulated egg laying in ser-4;mod-1 animals was greater than in wild-type animals, and ser-4;mod-1 animals retained fewer eggs than wild-type animals. Surprisingly, ser-4;mod-1;ser-7 ser-1 animals retained the same number of eggs as wild-type animals and exhibited significant 5-HT-stimulated egg laying that was dependent on a previously uncharacterized receptor, SER-5. 5-HT-stimulated egg laying was absent in ser-5;ser-4;mod-1;ser-7 ser-1 animals, and these animals retained more eggs than either wild-type or ser-4;mod-1;ser-7 ser-1 animals. The 5-HT sensitivity of egg laying could be restored by ser-5 muscle expression. Together, these results highlight the dual excitatory/inhibitory serotonergic inputs that combine to modulate egg laying.
血清素（5-羟色胺，5-HT）调节脊椎动物和无脊椎动物的关键生理过程。此前，在秀丽隐杆线虫中鉴定出了四种对5-HT调节产卵有作用的受体。因此，为了评估潜在的受体相互作用，我们培育了含有每个受体无效等位基因组合的动物，特别是只表达单个5-HT受体的动物。5-HT刺激的产卵和卵滞留与预测的兴奋性和抑制性血清素能输入的不同组合密切相关。例如，5-HT在ser-1、ser-7或ser-7 ser-1无效动物中不刺激产卵，并且ser-7 ser-1动物比野生型动物保留更多的卵。相比之下，5-HT在ser-4;mod-1动物中刺激的产卵量大于野生型动物，并且ser-4;mod-1动物比野生型动物保留更少的卵。令人惊讶的是，ser-4;mod-1;ser-7 ser-1动物保留的卵数量与野生型动物相同，并且表现出显著的5-HT刺激的产卵，这依赖于一种先前未被表征的受体SER-5。5-HT刺激的产卵在ser-5;ser-4;mod-1;ser-7 ser-1动物中不存在，并且这些动物比野生型或ser-4;mod-1;ser-7 ser-1动物保留更多的卵。ser-5在肌肉中的表达可以恢复产卵的5-HT敏感性。总之，这些结果突出了结合起来调节产卵的双重兴奋性/抑制性血清素能输入。
