Kouji Yasuyama
Department Kawasaki University of Medical Welfare , Position Professor with Special Assignment |
|
Article types | 原著 |
Language | English |
Peer review | Peer reviewed |
Title | Extraretinal photoreceptors at the compound eye's posterior margin in Drosophila melanogaster. |
Journal | Formal name:The Journal of comparative neurology Abbreviation:J Comp Neurol ISSN code:00219967/10969861 |
Volume, Issue, Page | 412(2),pp.193-202 |
Author and coauthor | Kouji Yasuyama, Meinertzhagen Ian A. |
Authorship | Lead author |
Publication date | 1999/09 |
Summary | 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 |