ヤスヤマ　コウジ   Kouji Yasuyama   泰山　浩司    所属   川崎医療福祉大学  リハビリテーション学部 言語聴覚療法学科    職種   特任教授
論文種別	原著
言語種別	英語
査読の有無	査読あり
表題	Extraretinal photoreceptors at the compound eye's posterior margin in Drosophila melanogaster.
掲載誌名	正式名：The Journal of comparative neurology 略　 称：J Comp Neurol ISSNコード：00219967/10969861
巻・号・頁	412(2),pp.193-202
著者・共著者	Kouji Yasuyama, Meinertzhagen Ian A.
担当区分	筆頭著者
発行年月	1999/09
概要	Many invertebrates have supplementary extraocular photoreceptors that often are implicated in circadian rhythms. An extraretinal group of candidate photoreceptors in the fruit fly, Drosophila melanogaster, has been revealed previously at the posterior margin of the compound eye by using a photoreceptor-specific monoclonal antibody (Hofbauer and Buchner [1989] Naturwissen 76:335–336), but it never has been characterized. Here, we report the fine structure of this cell cluster reported by Hofbauer and Buchner, which is called "eyelet," as well as the further candidacy of their visual pigment and neurotransmitter. Eyelet forms a specialized, pigmented organ with cells that have numerous microvilli arranged into coherent rhabdomeres. The presence of rhabdomeric microvilli is a defining feature of a photoreceptor, reported here for the first time in eyelet. The rhabdomeres exhibit Rh6 opsin-like immunoreactivity, which provides evidence that the photoreceptors are functional: they fail to immunostain with antibodies against NINAE (Rh1), Rh4, or Rh5. The photoreceptors have been shown previously to exhibit histamine-like immunoreactivity, but they also stain with a monoclonal antiserum raised against Drosophila choline acetyltransferase (ChAT), suggesting that the photoreceptors not only may contain histamine but also can synthesize acetylcholine. AChAT-immunoreactive axon bundle originating from eyelet terminates in the cortex of the anterior medulla. This bundle also is seen with reduced silver stains. Electron microscopic examination revealed four axon profiles of similar size in this bundle, indicating that eyelet contains at least four photoreceptors. The pathway of eyelet’s axon bundle coincides with the precocious pathway of Bolwig’s nerve that arises from the larval organ of sight. The origin and possible function of eyelet are discussed.
DOI	10.1002/(SICI)1096-9861