Department of Biology, Animal Physiology, University of Kassel, Heinrich-Plett-Str. 40, 34132, Kassel, Germany.
Cell Tissue Res. 2014 Feb;355(2):447-62. doi: 10.1007/s00441-013-1757-9. Epub 2013 Dec 10.
The circadian pacemaker controlling locomotor activity rhythms in the Madeira cockroach is located at the accessory medulla (AMe). The ipsi- and contralateral compound eyes provide light input to the AMe, possibly via the γ-aminobutyric acid (GABA)-immunoreactive (-ir) distal tract, which connects the glomeruli of the AMe to the ipsilateral medulla and lamina. To identify possible light-entrainment pathways, double-label immunocytochemistry was performed employing antibodies against GABA, myoinhibitory peptide (MIP), allatotropin (AT) and orcokinin (ORC). While all antisera tested, except the anti-ORC, prominently stained the glomeruli of the AMe, colocalization with anti-GABA was detected neither in the glomeruli nor in the distal tract. However, one median neuron that colocalized GABA-, AT- and MIP-immunoreactivity appeared to connect all glomeruli of the AMe to the medulla and lamina. Furthermore, one distal-frontoventral local neuron with arborizations in all glomeruli of the AMe colocalized anti-AT- and anti-MIP immunoreactivity. As candidates for contralateral light entrainment pathways, one ventromedian and one ventral neuron colocalized MIP- and ORC immunoreactivity, projecting via posterior and anterior commissures. Both branched in the interglomerular region of the AMe, where arborizations co-labeled with anti-ORC- and anti-MIP antisera. A possible role for MIP in light entrainment is supported also by injections of Rhyparobia maderae-specific MIP-2, which generated an all-advance phase-response curve late at night. Future experiments will challenge our hypothesis that GABA-, MIP- and AT-ir neurons provide ipsilateral light entrainment to all glomeruli, while MIP- and ORC-ir neurons carry contralateral light entrainment to the AMe's interglomerular region, either delaying or advancing AMe neurons light-dependently.
调控马德拉蜚蠊（Madeira cockroach）运动活动节律的生物钟位于附加脑髓（accessory medulla，AMe）。同侧和对侧复眼向 AMe 提供光输入，可能通过连接 AMe 肾小球与同侧脑髓和薄板的γ-氨基丁酸（GABA）免疫反应性（ir）远轴突。为了鉴定可能的光适应途径，采用针对 GABA、肌抑制肽（myoinhibitory peptide，MIP）、促咽侧体激素（allatotropin，AT）和奥卡宁（orcokinin，ORC）的抗体进行双标免疫细胞化学。虽然除了抗 ORC 之外的所有抗血清都显著标记 AMe 的肾小球，但在肾小球或远轴突中均未检测到与抗 GABA 的共定位。然而，一个与 GABA、AT 和 MIP 免疫反应性共定位的中间神经元似乎将 AMe 的所有肾小球连接到脑髓和薄板。此外，一个具有 AMe 所有肾小球分支的远端额腹侧局部神经元与抗 AT 和抗 MIP 免疫反应性共定位。作为对侧光适应途径的候选物，一个腹内侧和一个腹侧神经元与 MIP 和 ORC 免疫反应性共定位，通过后和前连合投射。两者在 AMe 的肾小球间区域分支，其中分支与抗 ORC 和抗 MIP 抗血清共标记。MIP 在光适应中的作用也得到了 Rhyparobia maderae 特异性 MIP-2 注射的支持，该注射在深夜产生了一个全提前的相位反应曲线。未来的实验将挑战我们的假设，即 GABA、MIP 和 AT-ir 神经元为所有肾小球提供同侧光适应，而 MIP 和 ORC-ir 神经元为 AMe 的肾小球间区域提供对侧光适应，使 AMe 神经元依赖光延迟或提前。
