Physiological responses of ionotropic histamine receptors, PxHCLA and PxHCLB, to neurotransmitter candidates in a butterfly, Papilio xuthus
Physiological responses of ionotropic histamine receptors, PxHCLA and PxHCLB, to neurotransmitter candidates in a butterfly, Papilio xuthus
复制标题
DOI：
10.1242/jeb.183129
复制
发表时间：
2018-11
影响因子：
2.8
通讯作者：
Hiroshi Akashi;Pei-Ju Chen;Tokiho Akiyama;Y. Terai;M. Wakakuwa;Yasunori Takayama;M. Tominaga;K. Ar
中科院分区：
文献类型：
--
作者：
Hiroshi Akashi;Pei-Ju Chen;Tokiho Akiyama;Y. Terai;M. Wakakuwa;Yasunori Takayama;M. Tominaga;K. Ar
组胺是节肢动物光感受器释放的唯一已知的神经递质。从光感受器到二级神经元的突触传递是由组胺门控氯离子通道（hcl）的激活介导的。这些组胺能突触被认为在昆虫的视觉系统中是保守的。然而，到目前为止，我们对这些通道的理解都是基于对苍蝇的研究。在蝴蝶凤蝶（Papilio xuthus）中，我们确定了两个候选的组胺门控氯离子通道PxHCLA和PxHCLB，并利用全细胞膜片钳技术研究了它们的生理特性。我们研究了培养细胞中表达的通道对组胺以及其他候选神经递质（即GABA、酪胺、血清素、d-/l-谷氨酸和甘氨酸）的反应。我们发现组胺和GABA都能激活PxHCLA和PxHCLB，而其他分子则没有。PxHCLB对组胺和GABA的敏感性始终高于PxHCLA。有趣的是，同时使用组胺和GABA比单独使用任何一种神经递质更能激活PxHCLA和PxHCLB；组胺和GABA可能在它们共同定位的区域对pxhcl具有协同作用。我们的研究结果表明，组胺受体的生理特性在昆虫中基本是保守的，但对GABA的反应在蝴蝶和苍蝇之间是不同的，这意味着不同物种之间的早期视觉加工存在差异。摘要：凤蝶视觉系统中两个组胺门控氯离子通道的鉴定与表征；这两个通道对组胺和GABA都有反应。
ABSTRACT Histamine is the only known neurotransmitter released by arthropod photoreceptors. Synaptic transmission from photoreceptors to second-order neurons is mediated by the activation of histamine-gated chloride channels (HCLs). These histaminergic synapses have been assumed to be conserved among insect visual systems. However, our understanding of the channels in question has thus far been based on studies in flies. In the butterfly Papilio xuthus, we have identified two candidate histamine-gated chloride channels, PxHCLA and PxHCLB, and studied their physiological properties using a whole-cell patch-clamp technique. We studied the responses of channels expressed in cultured cells to histamine as well as to other neurotransmitter candidates, namely GABA, tyramine, serotonin, d-/l-glutamate and glycine. We found that histamine and GABA activated both PxHCLA and PxHCLB, while the other molecules did not. The sensitivity to histamine and GABA was consistently higher in PxHCLB than in PxHCLA. Interestingly, simultaneous application of histamine and GABA activated both PxHCLA and PxHCLB more strongly than either neurotransmitter individually; histamine and GABA may have synergistic effects on PxHCLs in the regions where they co-localize. Our results suggest that the physiological properties of the histamine receptors are basically conserved among insects, but that the response to GABA differs between butterflies and flies, implying variation in early visual processing among species. Summary: Identification and characterization of two histamine-gated chloride channels in the visual system of Papilio; both channels respond to histamine as well as to GABA.