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Hirata K, Shiga S. Bolwig Organ and Its Role in the Photoperiodic Response of Sarcophaga similis Larvae. INSECTS 2023; 14:115. [PMID: 36835683 PMCID: PMC9959995 DOI: 10.3390/insects14020115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/18/2023] [Accepted: 01/20/2023] [Indexed: 06/18/2023]
Abstract
Flesh-fly Sarcophaga similis larvae exhibit a photoperiodic response, in which short days induce pupal diapause for seasonal adaptation. Although the spectral sensitivity of photoperiodic photoreception is known, the photoreceptor organ remains unclear. We morphologically identified the Bolwig organ, a larval-photoreceptor identified in several other fly species, and examined the effects of its removal on the photoperiodic response in S. similis. Backfill-staining and embryonic-lethal-abnormal-vision (ELAV) immunohistochemical-staining identified ~34 and 38 cells, respectively, in a spherical body at the ocular depression of the cephalopharyngeal skeleton, suggesting that the spherical body is the Bolwig organ in S. similis. Forward-fill and immunohistochemistry revealed that Bolwig-organ neurons terminate in the vicinity of the dendritic fibres of pigment-dispersing factor-immunoreactive and potential circadian-clock neurons in the brain. After surgical removal of the Bolwig-organ regions, diapause incidence was not significantly different between short and long days, and was similar to that in the insects with an intact organ, under constant darkness. However, diapause incidence was not significantly different between the control and Bolwig-organ-removed insects for each photoperiod. These results suggest that the Bolwig organ contributes partially to photoperiodic photoreception, and that other photoreceptors may also be involved.
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Affiliation(s)
- Kazuné Hirata
- Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka 560-0043, Osaka, Japan
- Center for Ecological Research, Kyoto University, Otsu 520-2133, Shiga, Japan
| | - Sakiko Shiga
- Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka 560-0043, Osaka, Japan
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Hamanaka Y, Lu Z, Shiga S. Morphology and synaptic connections of pigment-dispersing factor-immunoreactive neurons projecting to the lateral protocerebrum in the large black chafer, Holotrichia parallela. J Comp Neurol 2022; 530:2994-3010. [PMID: 35881849 DOI: 10.1002/cne.25391] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 06/30/2022] [Accepted: 07/01/2022] [Indexed: 11/08/2022]
Abstract
Pigment-dispersing factor (PDF) is a well-known output neuropeptide modulator of circadian pacemakers in insects. Here, we investigated PDF-immunoreactive (ir) neurons in the brain of the large black chafer Holotrichia parallela to search for circadian neural components, which are potentially involved in its circabidian rhythm. PDF-ir cells were exclusively detected near the accessory medulla (AME) as a cluster of ∼ 100 cells with almost homogeneous size. No other cells exhibited immunoreactivity. The PDF-ir cells send beaded fibers into the proximal half of the AME and ventral elongation in an anterior region between the medulla (ME) and lobula (LO). Neither the lamina, ME, LO, nor lobula plate receives PDF-ir fibers. Primary axons derived from the PDF-ir cells extend toward the contralateral hemisphere through the dorsolateral protocerebrum anterior to the calyx to connect the bilateral AME. The axons form varicose outgrowths exclusively in the lateral protocerebrum. Double labeling with antisynapsin revealed partial overlaps between PDF-ir varicosities and synapsin-ir puncta. Thus, it was assumed that the PDF-ir fibers form output synapses there. To verify this, we investigated the ultrastructure of the PDF-ir varicosities in the lateral protocerebrum by preembedding immunoelectron microscopy. The PDF-ir profiles contain small clear synaptic vesicles as well as both PDF-positive and PDF-negative dense-core vesicles, and the profiles form output synapses upon unknown profiles and receive synapses from other PDF-ir profiles. PDF neurons near the AME are considered to be prominent circadian pacemakers in the cockroach and flies. Their possible function in the circabidian rhythm was discussed based on these anatomical insights.
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Affiliation(s)
- Yoshitaka Hamanaka
- Laboratory of Comparative Neurobiology, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan
| | - Zhiyuan Lu
- Department of Psychology and Neuroscience, Life Sciences Centre, Dalhousie University, Halifax, Canada
| | - Sakiko Shiga
- Laboratory of Comparative Neurobiology, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan
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Schlichting M. Entrainment of the Drosophila clock by the visual system. Neurosci Insights 2020; 15:2633105520903708. [PMID: 35174330 PMCID: PMC8842342 DOI: 10.1177/2633105520903708] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 01/08/2020] [Indexed: 12/27/2022] Open
Abstract
Circadian clocks evolved as an adaptation to the cyclic change of day and night. To precisely adapt to this environment, the endogenous period has to be adjusted every day to exactly 24 hours by a process called entrainment. Organisms can use several external cues, called zeitgebers, to adapt. These include changes in temperature, humidity, or light. The latter is the most powerful signal to synchronize the clock in animals. Research shows that a complex visual system and circadian photoreceptors work together to adjust animal physiology to the outside world. This review will focus on the importance of the visual system for clock synchronization in the fruit fly Drosophila melanogaster. It will cover behavioral and physiological evidence that supports the importance of the visual system in light entrainment.
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Desensitization and recovery of crayfish photoreceptors. Dependency on circadian time, and pigment-dispersing hormone. Comp Biochem Physiol A Mol Integr Physiol 2016; 203:297-303. [PMID: 27783925 DOI: 10.1016/j.cbpa.2016.10.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 10/17/2016] [Accepted: 10/19/2016] [Indexed: 12/20/2022]
Abstract
In this work, we studied the characteristics of recovery from desensitization of the light-elicited current of crayfish. Applying a two-flash protocol, we found that the first flash triggers a current that activates with a noticeable latency, reaches a peak value, and thereafter decays along a single exponential time course. In comparison with the first-elicited current, the current elicited by the second flash not only presents an expected smaller peak current, depending on the time between flashes, but it also displays a different latency and decay time constant. Recovery of the first flash values of these current parameters depends on the circadian time at which the experiments are conducted, and on the presence of pigment-dispersing hormone. Our data also suggest the existence of distinctive desensitized states, whose induction depends on circadian time and the presence of pigment-dispersing hormone.
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Yasuyama K, Hase H, Shiga S. Neuroanatomy of pars intercerebralis neurons with special reference to their connections with neurons immunoreactive for pigment-dispersing factor in the blow fly Protophormia terraenovae. Cell Tissue Res 2015; 362:33-43. [PMID: 25971932 DOI: 10.1007/s00441-015-2192-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 04/02/2015] [Indexed: 11/30/2022]
Abstract
Input regions of pars intercerebralis (PI) neurons are examined by confocal and electron microscopies with special reference to their connections with neurons immunoreactive for pigment-dispersing factor (PDF) in the blow fly, Protophormia terraenovae. PI neurons are a prerequisite for ovarian development under long-day conditions. Backfills from the cardiac recurrent nerve after severance of the posterior lateral tracts labeled thin fibers derived from the PI neurons in the superior medial protocerebrum. These PI fibers were mainly synapsin-negative and postsynaptic to unknown varicose profiles containing dense-core vesicles. Backfilled fibers in the periesophageal neuropils, derived from the PI neurons or neurons with somata in the subesophageal zone, were varicose and some were synapsin-positive. Electron microscopy revealed the presence of both presynaptic and postsynaptic sites in backfilled fibers in the periesophageal neuropils. Many PDF-immunoreactive varicosities were found in the superior medial and lateral protocerebrum and double-labeling showed that 60-88 % of PDF-immunoreactive varicosities were also synapsin-immunoreactive. Double-labeling with the backfills and PDF immunocytochemistry showed that the PI fibers and PDF-immunoreactive varicosities were located close to each other in the superior medial protocerebrum. Results of triple-labeling of PI neurons, PDF-immunoreactive neurons and synapsin-immunoreactive terminals demonstrated that the synapsin-positive PDF-immunoreactive varicosities contacted the PI fibers. These data suggest that PI neurons receive synaptic contacts from PDF-immunoreactive fibers, which are derived from circadian clock neurons, of small ventral lateral neurons (previously called OL2) or posterior dorsal (PD) neurons with somata in the pars lateralis.
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Affiliation(s)
- Kouji Yasuyama
- Division of Biology, Department of Natural Sciences, Kawasaki Medical School, Kurashiki, Okayama, 701-0192, Japan
| | - Hiroaki Hase
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan
| | - Sakiko Shiga
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan.
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Karsai G, Pollák E, Wacker M, Vömel M, Selcho M, Berta G, Nachman RJ, Isaac RE, Molnár L, Wegener C. Diverse in- and output polarities and high complexity of local synaptic and non-synaptic signaling within a chemically defined class of peptidergic Drosophila neurons. Front Neural Circuits 2013; 7:127. [PMID: 23914156 PMCID: PMC3729985 DOI: 10.3389/fncir.2013.00127] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 07/12/2013] [Indexed: 12/31/2022] Open
Abstract
Peptidergic neurons are not easily integrated into current connectomics concepts, since their peptide messages can be distributed via non-synaptic paracrine signaling or volume transmission. Moreover, the polarity of peptidergic interneurons in terms of in- and out-put sites can be hard to predict and is very little explored. We describe in detail the morphology and the subcellular distribution of fluorescent vesicle/dendrite markers in CCAP neurons (NCCAP), a well defined set of peptidergic neurons in the Drosophila larva. NCCAP can be divided into five morphologically distinct subsets. In contrast to other subsets, serial homologous interneurons in the ventral ganglion show a mixed localization of in- and output markers along ventral neurites that defy a classification as dendritic or axonal compartments. Ultrastructurally, these neurites contain both pre- and postsynaptic sites preferably at varicosities. A significant portion of the synaptic events are due to reciprocal synapses. Peptides are mostly non-synaptically or parasynaptically released, and dense-core vesicles and synaptic vesicle pools are typically well separated. The responsiveness of the NCCAP to ecdysis-triggering hormone may be at least partly dependent on a tonic synaptic inhibition, and is independent of ecdysteroids. Our results reveal a remarkable variety and complexity of local synaptic circuitry within a chemically defined set of peptidergic neurons. Synaptic transmitter signaling as well as peptidergic paracrine signaling and volume transmission from varicosities can be main signaling modes of peptidergic interneurons depending on the subcellular region. The possibility of region-specific variable signaling modes should be taken into account in connectomic studies that aim to dissect the circuitry underlying insect behavior and physiology, in which peptidergic neurons act as important regulators.
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Affiliation(s)
- Gergely Karsai
- Department of Comparative Anatomy and Developmental Biology, Institute of Biology, Faculty of Science, University of Pécs Pécs, Hungary ; Neurobiology and Genetics, Biocenter, Theodor-Boveri-Institute, University of Würzburg Würzburg, Germany
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Shiga S. Plausible neural circuitry for photoperiodism in the blow fly, Protophormia terraenovae. ACTA BIOLOGICA HUNGARICA 2012; 63 Suppl 2:36-47. [PMID: 22776471 DOI: 10.1556/abiol.63.2012.suppl.2.3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Photoperiodism is important for seasonal adaptation in insects. Although photoreceptors and endocrine outputs for photoperiodism have been investigated, its neural mechanisms are less studied. This paper proposes three groups of neurons involved in photoperiodic control of adult diapause in the blow fly, Protophormia terraenovae. Ablation experiments showed that pars lateralis neurons in the dorsal protocerebrum are important for diapause induction under short-days and low temperature, the pars intercerebralis neurons for ovarian development under long-days and high temperature. When regions containing pigment-dispersing factor and PERIOD immunoreactive s-LNvs were bilaterally ablated, flies became arrhythmic in locomotor activities, and did not discriminate photoperiod for diapause induction, suggesting that s-LNvs are important for circadian rhythm and photoperiodism. In the s-LNvs, PERIOD-immunoreactivity in the nucleus was highest at 12 h after lights-off and lowest 12 h after lights-on regardless of photoperiod. Thus, as in D. melanogaster, it is possible that PERIOD nuclear translocation entrains to photoperiod, and day-length information seems to be encoded in s-LNvs. Immunoelectronmicroscopy revealed synaptic connections from s-LNvs to the pars lateralis neurons, suggesting that circadian clock neurons, s-LNvs, are involved in time measurements and may synaptically signal day-length information to the pars lateralis neurons.
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Affiliation(s)
- Sakiko Shiga
- Osaka City University Department of Biology and Geosciences, Graduate School of Science Sumiyoshi, Osaka 558-8585 Japan
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Identifying specific light inputs for each subgroup of brain clock neurons in Drosophila larvae. J Neurosci 2012; 31:17406-15. [PMID: 22131402 DOI: 10.1523/jneurosci.5159-10.2011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In Drosophila, opsin visual photopigments as well as blue-light-sensitive cryptochrome (CRY) contribute to the synchronization of circadian clocks. We focused on the relatively simple larval brain, with nine clock neurons per hemisphere: five lateral neurons (LNs), four of which express the pigment-dispersing factor (PDF) neuropeptide, and two pairs of dorsal neurons (DN1s and DN2s). CRY is present only in the PDF-expressing LNs and the DN1s. The larval visual organ expresses only two rhodopsins (RH5 and RH6) and projects onto the LNs. We recently showed that PDF signaling is required for light to synchronize the CRY(-) larval DN2s. We now show that, in the absence of functional CRY, synchronization of the DN1s also requires PDF, suggesting that these neurons have no direct connection with the visual system. In contrast, the fifth (PDF(-)) LN does not require the PDF-expressing cells to receive visual system inputs. All clock neurons are light-entrained by light-dark cycles in the rh5(2);cry(b), rh6(1) cry(b), and rh5(2);rh6(1) double mutants, whereas the triple mutant is circadianly blind. Thus, any one of the three photosensitive molecules is sufficient, and there is no other light input for the larval clock. Finally, we show that constant activation of the visual system can suppress molecular oscillations in the four PDF-expressing LNs, whereas, in the adult, this effect of constant light requires CRY. A surprising diversity and specificity of light input combinations thus exists even for this simple clock network.
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Meelkop E, Temmerman L, Schoofs L, Janssen T. Signalling through pigment dispersing hormone-like peptides in invertebrates. Prog Neurobiol 2010; 93:125-47. [PMID: 21040756 DOI: 10.1016/j.pneurobio.2010.10.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Revised: 10/19/2010] [Accepted: 10/21/2010] [Indexed: 12/19/2022]
Abstract
During recent decades, several research teams engaged in unraveling the molecular structure and the physiological significance of pigment dispersing hormone-like peptides, particularly with respect to colour change and biological rhythms. In this review, we first summarise the entire history of pigment dispersing hormone-like peptide research, thus providing a stepping stone for those who are curious about this growing area of interest. Next, we try to bring order in the plethora of experimental data on the molecular structure of the various peptides and receptors and also discuss immunolocalization, time-related expression and suggested functions in crustaceans, insects and nematodes. In addition, a brief comparison with the vertebrate system is made.
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Affiliation(s)
- E Meelkop
- Laboratory of Functional Genomics and Proteomics, Zoological Institute, K.U. Leuven, Naamsestraat 59, B-3000 Leuven, Belgium
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Yasuyama K, Meinertzhagen IA. Synaptic connections of PDF-immunoreactive lateral neurons projecting to the dorsal protocerebrum ofDrosophila melanogaster. J Comp Neurol 2010; 518:292-304. [DOI: 10.1002/cne.22210] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Sullivan JM, Genco MC, Marlow ED, Benton JL, Beltz BS, Sandeman DC. Brain photoreceptor pathways contributing to circadian rhythmicity in crayfish. Chronobiol Int 2009; 26:1136-68. [PMID: 19731110 DOI: 10.3109/07420520903217960] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Freshwater crayfish have three known photoreceptive systems: the compound eyes, extraretinal brain photoreceptors, and caudal photoreceptors. The primary goal of the work described here was to explore the contribution of the brain photoreceptors to circadian locomotory activity and define some of the underlying neural pathways. Immunocytochemical studies of the brain photoreceptors in the parastacid (southern hemisphere) crayfish Cherax destructor reveal their expression of the blue light-sensitive photopigment cryptochrome and the neurotransmitter histamine. The brain photoreceptors project to two small protocerebral neuropils, the brain photoreceptor neuropils (BPNs), where they terminate among fibers expressing the neuropeptide pigment-dispersing hormone (PDH), a signaling molecule in arthropod circadian systems. Comparable pathways are also described in the astacid (northern hemisphere) crayfish Procambarus clarkii. Despite exhibiting markedly different diurnal locomotor activity rhythms, removal of the compound eyes and caudal photoreceptors in both C. destructor and P. clarkii (leaving the brain photoreceptors intact) does not abolish the normal light/dark activity cycle in either species, nor prevent the entrainment of their activity cycles to phase shifts of the light/dark period. These results suggest, therefore, that crayfish brain photoreceptors are sufficient for the entrainment of locomotor activity rhythms to photic stimuli, and that they can act in the absence of the compound eyes and caudal photoreceptors. We also demonstrate that the intensity of PDH expression in the BPNs varies in phase with the locomotor activity rhythm of both crayfish species. Together, these findings suggest that the brain photoreceptor cells can function as extraretinal circadian photoreceptors and that the BPN represents part of an entrainment pathway synchronizing locomotor activity to environmental light/dark cycles, and implicating the neuropeptide PDH in these functions.
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Affiliation(s)
- Jeremy M Sullivan
- Neuroscience Program, Wellesley College, Wellesley, Massachusetts 02481, USA
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Johard HA, Yoishii T, Dircksen H, Cusumano P, Rouyer F, Helfrich-Förster C, Nässel DR. Peptidergic clock neurons inDrosophila: Ion transport peptide and short neuropeptide F in subsets of dorsal and ventral lateral neurons. J Comp Neurol 2009; 516:59-73. [DOI: 10.1002/cne.22099] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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13
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Abstract
Molecular genetics has revealed the identities of several components of the fundamental circadian molecular oscillator - an evolutionarily conserved molecular mechanism of transcription and translation that can operate in a cell-autonomous manner. Therefore, it was surprising when studies of circadian rhythmic behavior in the fruit fly Drosophila suggested that the normal operations of circadian clock cells, which house the molecular oscillator, in fact depend on non-cell-autonomous effects - interactions between the clock cells themselves. Here we review several genetic analyses that broadly extend that viewpoint. They support a model whereby the approximately 150 circadian clock cells in the brain of the fly are sub-divided into functionally discrete rhythmic centers. These centers alternatively cooperate or compete to control the different episodes of rhythmic behavior that define the fly's daily activity profile.
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Affiliation(s)
- Michael N Nitabach
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
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Miśkiewicz K, Schürmann FW, Pyza E. Circadian release of pigment-dispersing factor in the visual system of the housefly,Musca domestica. J Comp Neurol 2008; 509:422-35. [DOI: 10.1002/cne.21765] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Helfrich-Förster C, Shafer OT, Wülbeck C, Grieshaber E, Rieger D, Taghert P. Development and morphology of the clock-gene-expressing lateral neurons of Drosophila melanogaster. J Comp Neurol 2007; 500:47-70. [PMID: 17099895 DOI: 10.1002/cne.21146] [Citation(s) in RCA: 171] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The clock-gene-expressing lateral neurons are essential for the locomotor activity rhythm of Drosophila melanogaster. Traditionally, these neurons are divided into three groups: the dorsal lateral neurons (LN(d)), the large ventral lateral neurons (l-LN(v)), and the small ventral lateral neurons (s-LN(v)), whereby the latter group consists of four neurons that express the neuropeptide pigment-dispersing factor (PDF) and a fifth PDF-negative neuron. So far, only the l-LN(v) and the PDF-positive s-LN(v) have been shown to project into the accessory medulla, a small neuropil that contains the circadian pacemaker center in several insects. We show here that the other lateral neurons also arborize in the accessory medulla, predominantly forming postsynaptic sites. Both the l-LN(v) and LN(d) are anatomically well suited to connect the accessory medullae. Whereas the l-LN(v) may receive ipsilateral photic input from the Hofbauer-Buchner eyelet, the LN(d) invade mainly the contralateral accessory medulla and thus may receive photic input from the contralateral side. Both the LN(d) and the l-LN(v) differentiate during midmetamorphosis. They do so in close proximity to one another and the fifth PDF-negative s-LN(v), suggesting that these cell groups may derive from common precursors.
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