Abdominal Ganglion Research Articles

Control of copula duration and sperm storage by female Queensland fruit flies

Copula duration and sperm storage patterns can directly or indirectly affect fitness of male and female insects. Although both sexes have an interest in the outcome, research has tended to focus on males. To investigate female influences, we compared copula duration and sperm storage of Queensland fruit fly females that were intact, or had been incapacitated through decapitation or abdomen isolation. We found that copulations were far longer when females had been incapacitated, indicating that constraints imposed on copula duration by intact females had been relaxed. Repeatability of copula duration for males was very low regardless of female treatment, and this is also consistent with strong female influence. Number of sperm in the spermathecae was not influenced by female treatment, suggesting that female abdominal ganglia control the transport of sperm to these long-term storage organs. However, more sperm were found in the ventral receptacles of incapacitated females compared to intact females. Overall, results implicate cephalic ganglia in regulation of copula duration and short-term sperm storage in the ventral receptacle and abdominal ganglia in regulation of long-term sperm storage in the spermathecae.

Cyclic-GMP levels in abdominal ganglia of the silkmoth, Bombyx mori at the time of eclosion

Cyclic-GMP levels in abdominal ganglia of the silkmoth, Bombyx mori at the time of eclosion

Cloning and distribution of a putative octopamine/tyramine receptor in the central nervous system of the freshwater prawn Macrobrachium rosenbergii

There is ample evidence linking octopamine (OA) and tyramine (TA) to several neurophysiological functions in arthropods. In our laboratory we use the freshwater prawn Macrobrachium rosenbergii to study the neural basis of aggressive behavior. As a first step towards understanding the possible role of these amines and their receptors in the modulation of interactive behaviors, we have cloned a putative octopamine/tyramine receptor. The predicted sequence of the cloned OA/TA Mac receptor consists of 1,579 base pairs (bp), with an open reading frame of 1,350 bp that encodes a 450 amino acid protein. This putative protein displays sequence identities of 70% to an Aedes aegypti mosquito TA receptor, followed by 60% to a Stegomyia aegypti mosquito OA receptor, 59% and 58% to the migratory locust TA-1 and -2 receptors respectively, and 57% with the silkworm OA receptor. We also mapped the OA/TA Mac receptor distribution by in-situ hybridization to the receptor's mRNA, and by immunohistochemistry to its protein. We observed stained cell bodies for the receptor's mRNA, mainly in the midline region of the thoracic and in the abdominal ganglia, as well as diffuse staining in the brain ganglia. For the receptor's protein, we observed extensive punctate staining within the neuropil and on the membrane of specific groups of neurons in all ganglia throughout the CNS, including the brain, the midline region and neuropiles of the thoracic ganglia, and ventral part and neuropiles of the abdominal ganglia. The same pattern of stained cells was observed on the thoracic and abdominal ganglia in both in-situ hybridization and immunohistochemistry experiments. Diffuse staining observed with in-situ hybridization also coincides with punctate staining observed in brain, SEG, thoracic, and abdominal ganglia in immunohistochemical preparations. This work provides the first step towards characterizing the neural networks that mediate octopaminergic signaling in prawn.

Sexual Dimorphism in Shape and Distribution of GABA-Like Immuno-Reactive Neurons in Cricket Terminal Abdominal Ganglion

We studied age-related sexual dimorphism of the terminal abdominal ganglion in the cricket, Gryllus bimaculatus using osmium/ethyl-gallate staining and GABA immunohistochemistry. We determinedthat the volume of the terminal abdominal ganglion increases with increasing body size. The growth ratio between longitude and width in the terminal abdominal ganglion is the same in all nymph stages and sexes. However, the longitudinal growth of the male terminal abdominal ganglion ceases in the 8th instar and the adult stage. Therefore, in the adult stage, sexual dimorphism is observed in ganglion morphology. Additionally, sexual dimorphism is also observed in numbers of neuronal somata and GABA-like immunoreactive neurons in the terminal abdominal ganglion. At the beginning of the 8th instar, the number of somata is greater in female crickets than in males. GABA-like immunoreactive neurons, which were classified into eight clusters, increased between the 8th instar and adult in both sexes, but their numbers were sexually dimorphic in the 7th and 8th instars, and in the adult. Females had a greater number of GABA-like immunoreactive neurons than males. These differences occurred mainly in the 8th neuromere cluster, as well as the anterior region of the 9-11th neuromeres.

Neural substrate and allatostatin-like innervation of the gut of Locusta migratoria

Allatostatin-like immunoreactivity (ALI) is widely distributed in processes and varicosities on the fore-, mid-, and hindgut of the locust, and within midgut open-type endocrine-like cells. ALI is also observed in cells and processes in all ganglia of the central nervous system (CNS) and the stomatogastric nervous system (SNS). Ventral unpaired median neurons (VUMs) contained ALI within abdominal ganglia IV–VII. Neurobiotin retrograde fills of the branches of the 11th sternal nerve that innervate the hindgut revealed 2–4 VUMs in abdominal ganglia IV–VIIth, which also contain ALI. The VIIIth abdominal ganglion contained three ventral medial groups of neurons that filled with neurobiotin and contained ALI. The co-localization of ALI in the identified neurons suggests that these cells are the source of ALI on the hindgut. A retrograde fill of the nerves of the ingluvial ganglia that innervate the foregut revealed numerous neurons within the frontal ganglion and an extensive neuropile in the hypocerebral ganglion, but there seems to be no apparent co-localization of neurobiotin and ALI in these neurons, indicating the source of ALI on the foregut comes via the brain, through the SNS.

Circadian oscillations outside the optic lobe in the cricket Gryllus bimaculatus

Although circadian rhythms are found in many peripheral tissues in insects, the control mechanism is still to be elucidated. To investigate the central and peripheral relationships in the circadian organization, circadian rhythms outside the optic lobes were examined in the cricket Gryllus bimaculatus by measuring mRNA levels of period ( per) and timeless ( tim) genes in the brain, terminal abdominal ganglion (TAG), anterior stomach, mid-gut, testis, and Malpighian tubules. Except for Malpighian tubules and testis, the tissues showed a daily rhythmic expression in either both per and tim or tim alone in LD. Under constant darkness, however, the tested tissues exhibited rhythmic expression of per and tim mRNAs, suggesting that they include a circadian oscillator. The amplitude and the levels of the mRNA rhythms varied among those rhythmic tissues. Removal of the optic lobe, the central clock tissue, differentially affected the rhythms: the anterior stomach lost the rhythm of both per and tim; in the mid-gut and TAG, tim expression became arrhythmic but per maintained rhythmic expression; a persistent rhythm with a shifted phase was observed for both per and tim mRNA rhythms in the brain. These data suggest that rhythms outside the optic lobe receive control from the optic lobe to different degrees, and that the oscillatory mechanism may be different from that of Drosophila.

Can high-field MREIT be used to directly detect neural activity? Theoretical considerations

We sought to determine the feasibility of directly studying neural tissue activity by analysis of differential phase shifts in MRI signals that occurred when trickle currents were applied to a bath containing active or resting neural tissue. We developed a finite element bidomain model of an aplysia abdominal ganglion in order to estimate the sensitivity of this contrast mechanism to changes in cell membrane conductance occurring during a gill-withdrawal reflex. We used our model to determine both current density and magnetic potential distributions within a sample chamber containing an isolated ganglion when it was illuminated with current injected synchronously with the MR imaging sequence and predicted the resulting changes in MRI phase images. This study provides the groundwork for attempts to image neural function using Magnetic Resonance Electrical Impedance Tomography (MREIT). We found that phase noise in a candidate 17.6T MRI system should be sufficiently low to detect phase signal differences between active and resting membrane states at resolutions around 1mm3. We further delineate the broad dependencies of signal-to-noise ratio on activity frequency, current application time and active tissue fractions and outline strategies that can be used to lower phase noise below that presently observed in conventional MREIT techniques. We also propose the idea of using MREIT as an alternative means of studying neuromodulation.

A new role for photoresponsive neurons called simple photoreceptors in the sea slug Onchidium verruculatum: Potentiation of synaptic transmission and motor response

The simple photoreceptors Ip-1 and Ip-2 are intrinsically light-sensitive neurons that exist in the abdominal ganglion of the sea slug Onchidium verruculatum. Using isolated ganglia and semi-intact or intact animal preparations, the present studies examined the light-sensing and physiological roles of Ip-1 and Ip-2 cells, which respond jointly to light by inducing a slow hyperpolarizing receptor potential. First, the synaptic inputs received by Ip-1 and Ip-2 and the axonal branches arising from their cell bodies were investigated. We found that these cells are not only first-order photosensory neurons, but also second-order neurons (interneurons), relaying inhibitory synaptic inputs such as water pressure and/or tactile senses. The amphibian Onchidium opens a pneumostome at low tide in order to aero-breathe. This pneumostome opening; i.e., aero-breathing behavior, was produced by spike discharges of Ip-1 and Ip-2 cells. Furthermore, the present results suggested that the hyperpolarizing photoresponse of Ip-1 and Ip-2 cells operates in the potentiation of inhibitory sensory synaptic transmission. Thus, we conclude that the simple photoreceptors of Onchidium play a role in the long-lasting potentiation of synaptic transmission and the subsequent behavioral response and so may be involved in a new photosensory modality, non-image-forming vision.

Coordination of spermathecal muscle activity with oviposition in Locusta migratoria.

Event Abstract Back to Event Coordination of spermathecal muscle activity with oviposition in Locusta migratoria. Angela Lange1* and Rosa Da Silva1 1 University of Toronto Mississauga, Department of Biology, Canada The spermatheca, oviducts and oviposition digging muscles are under neural and neuromodulatory control of a variety of neuroactive chemicals, including biogenic amines and neuropeptides. Some of these neuroactive chemicals are released following appropriate neural activity and help coordinate the activity of these reproductive tissues such that eggs are fertilized and deposited at appropriate times. Electrophysiological recordings were conducted to determine the control of spermathecal contractions during oviposition of interrupted egg-laying locusts. Following transection of the central nervous system below the metathoracic ganglion, rhythmic patterned bursting was observed in the nerve, N2B2 that innervates the spermatheca. Subsequent transections at more posterior regions of the ventral nerve cord revealed more robust rhythmic bursting in N2B2. This rhythmic bursting pattern was found to be coordinated with bursting in the ventral opener nerve that innervates the ventral opener muscle. This muscle controls the ventral ovipositor valves. Electromyographic recordings from the spermathecal muscle and ventral opener muscle confirmed rhythmic bursting resulted in an increase in muscle activity with observable muscle contractions. Taken together, the results indicate that there is likely a central pattern generator (CPG) that is regulated by descending inhibition that controls the spermathecal muscle activity. This CPG appears to be localized within the VIIth and VIIIth abdominal ganglia, and was found to integrate with the CPG that regulates oviposition digging in locusts. These results provide further insight into the intricate coordination and control of reproductive tissues underlying reproductive behaviours in locusts. Acknowledgements This study was supported by NSERC Keywords: comparative endocrinology Conference: 25th Conference of the European Comparative Endocrinologists, Pécs, Hungary, 31 Aug - 4 Sep, 2010. Presentation Type: Conference Presentation Topic: Comparative endocrinology Citation: Lange A and Da Silva R (2010). Coordination of spermathecal muscle activity with oviposition in Locusta migratoria.. Front. Endocrinol. Conference Abstract: 25th Conference of the European Comparative Endocrinologists. doi: 10.3389/conf.fendo.2010.01.00045 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 26 Aug 2010; Published Online: 29 Aug 2010. * Correspondence: Dr. Angela Lange, University of Toronto Mississauga, Department of Biology, Mississauga, Canada, angela.lange@utoronto.ca Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Angela Lange Rosa Da Silva Google Angela Lange Rosa Da Silva Google Scholar Angela Lange Rosa Da Silva PubMed Angela Lange Rosa Da Silva Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

RNA-Interference Knockdown of Drosophila Pigment Dispersing Factor in Neuronal Subsets: The Anatomical Basis of a Neuropeptide's Circadian Functions

BackgroundIn animals, neuropeptide signaling is an important component of circadian timekeeping. The neuropeptide pigment dispersing factor (PDF) is required for several aspects of circadian activity rhythms in Drosophila.Methodology/Principal FindingsHere we investigate the anatomical basis for PDF's various circadian functions by targeted PDF RNA-interference in specific classes of Drosophila neuron. We demonstrate that PDF is required in the ventro-lateral neurons (vLNs) of the central brain and not in the abdominal ganglion for normal activity rhythms. Differential knockdown of PDF in the large or small vLNs indicates that PDF from the small vLNs is likely responsible for the maintenance of free-running activity rhythms and that PDF is not required in the large vLNs for normal behavior. PDF's role in setting the period of free-running activity rhythms and the proper timing of evening activity under light:dark cycles emanates from both subtypes of vLN, since PDF in either class of vLN was sufficient for these aspects of behavior.Conclusions/SignificanceThese results reveal the neuroanatomical basis PDF's various circadian functions and refine our understanding of the clock neuron circuitry of Drosophila.

Biochemical Analysis and lmmunohistochemical Examination of a GnRH-like Immunoreactive Peptide in the Central Nervous System of a Decapod Crustacean, the Kuruma Prawn (Marsupenaeus japonicus)

We examined whether a gonadotropin-releasing hormone (GnRH)-like peptide exists in the central nervous system (CNS) of the kuruma prawn, Marsupenaeus japonicus, by reverse-phase high performance liquid chromatography (rpHPLC) combined with time-resolved fluoroimmunoassay (TR-FIA) analysis and by immunohistochemistry. The displacement curve obtained for serially diluted extracts of the kuruma prawn brain paralleled the chicken GnRH-II (cGnRH-II) standard curve obtained by cGnRH-II TR-FIA using the anti-cGnRH-II antibody, which cross-reacts not only with cGnRH-II but also with lamprey GnRH-II (lGnRH-II) and octopus GnRH (octGnRH). Extracts of kuruma prawn brains and eyestalks showed a similar retention time to synthetic lGnRH-II and octGnRH in rpHPLC combined with TR-FIA analysis. Using this antibody, we detected GnRH-like-immunoreactive (ir) cell bodies in the anterior-most part of the supraesophageal ganglion (brain), the protocerebrum. Furthermore, GnRH-like-ir fibers were observed in the protocerebrum and deutocerebrum. In the eyestalk, GnRH-like-ir cell bodies were detected in the medulla interna, and GnRH-like-ir fibers were distributed in the medulla interna, medulla externa, and lamina ganglionalis. In the thoracic ganglion, GnRH-like-ir fibers, but not GnRH-like-ir cell bodies, were detected. No GnRH-like-ir cell bodies or fibers were detected in the abdominal ganglion or ovary. Thus, we have shown the existence and distribution of a GnRH-like peptide in the CNS of the kuruma prawn.

Neuromuscular systems in the fifth instar larva of silkworm Bombyx mori (Lepidoptera: Bombycidae): II- Abdominal musculature and its innervation

The gross organisation of abdominal musculature and its innervation by segmental ganglionic nerves were studied in the fifth instar larva of Bombyx mori. The musculature comprises dorsal, ventral and lateral groups of muscles, represented as external and internal layers. The dorsal group includes musculi dorsales interni mediales (DIM), musculi dorsales externi mediales (DEM), musculi dorsales interni laterals (DIL) and musculi dorsales externi laterales (DEL). The ventral group includes musculi ventrales interni mediales (VIM), musculi ventralesexterni mediales (VEM), musculi ventrales interni laterales (VIL) and musculi ventrales externi laterales (VEL). The lateral group is represented by musculi laterales interni (LI) and musculi laterales externi (LE). The abdominal muscles are innervated by the dorsal (DN) and ventral (VN) nerves of abdominal ganglia. The DN innervates ventral internal, lateral internal and both dorsal external and internal muscles, while the VN innervates ventral external and lateral muscles. The sensory branches of DN and VN innervate the bodywall in the dorsal and ventral regions respectively with a sort of overlapping in the lateral region. The neuromuscular integration and intersegmental coordination in the abdominal region is discussed with reference to locomotion in the silkworm larva.

Detailed analysis of leucokinin-expressing neurons and their candidate functions in the Drosophila nervous system

The distribution of leucokinin (LK) neurons in the central nervous system (CNS) of Drosophila melanogaster was described by immunolabelling many years ago. However, no detailed underlying information of the input or output connections of their neurites was then available. Here, we provide a more accurate morphological description by employing a novel LK-specific GAL4 line that recapitulates LK expression. In order to analyse the possible afferent and efferent neural candidates of LK neurons, we used this lk-GAL4 line together with other CNS-Gal4 lines, combined with antisera against various neuropeptides or neurotransmitters. We found four kinds of LK neurons in the brain. (1) The lateral horn neurons connect the antennal glomerula to the mushroom bodies. (2) The suboesophageal neurons connect the gustatory receptors to the suboesophageal ganglia and ventral nerve cord. (3) The anterior neurons innervate the corpus cardiacum of the ring gland but LK expression is surprisingly not detectable from the third instar onwards in these neurons. (4) A set of abdominal ganglion neurons connect to the dorsal median tract in larvae and send their axons to a segmental muscle 8. Thus, the methods employed in our study can be used to identify individual neuropeptidergic neurons and thereby characterize functional cues or developmental transformations in their differentiation.

Characterization of neuronal apoptosis in the ventral ganglia of postembryonic silkworms Bombyx mori (Lepidoptera: Bombycidae)

A fluorescent triple staining method was developed to stain the cytoplasm of neurons red, the nuclei of all kinds of cells, including neurons, blue and the nuclei of apoptotic neurons in cyan in the twelve ventral ganglia (VG) of the Bombyx mori ventral nerve cord. This differential staining method was used to distinguish between apoptotic and normal neurons in the suboesophageal ganglion (SOG), thoracic ganglia (TG)1 to TG3 and abdominal ganglia (AG)1 to AG8 and also determine the changes in the num- bers of apoptotic neurons that occur during postembryonic development. In most of the VG tested, neuronal apoptosis was most marked during the period from the end of larval life to the mid pupal stage. The greatest number of apoptotic neurons was found in SOG of day-5 pupae, TG1 to TG3 and AG1 to AG4 of day-1 pupae, and AG5 to AG8 of day-4 pupae. In vivo injection of 20- hydroxyecdysone (20E) into day-8 5th instar larvae resulted in both a considerable increase in the number of apoptotic neurons and cleavage of procaspase-3 into caspase-3, which induced neuronal apoptosis in SOG and AG6 to AG8 in day-1 pupae, and a slight increase in the number of apoptotic neurons in TG1. In TG3 and AG4, however, it had little effect on the number of apoptotic neu- rons or cleavage of procaspase-3. Treatment of the VG of both day-8 5th instar larvae and day-2 pupae with protein synthesis inhibi- tors by in vivo injection triggered a significant inhibition of neuronal apoptosis and procaspase-3 cleavage in most of these ganglia in day-1 pupae and day-4 pupae, but not TG3 and AG4, in which there was little procaspase-3 and caspase-3. In vivo injection of caspase-8 and -3 inhibitors into day-8 5th instar larvae and day-2 pupae led to a substantial inhibition of neuronal apoptosis and of procaspase-3 cleavage in SOG, AG6 and TAG, but not in TG3 or AG4 of day-1 pupae and day-4 pupae. These findings suggest that neurons that die in SOG, TG1 and AG6 to AG8 in day-1 and -4 pupae may undergo apoptosis induced by the synthesis of a new pro- tein and caspase-8- and -3-implicated signal transduction by the increase in titre of 20E in the haemolymph but not the neuronal aopotosis in TG3 and AG4. This study provides neurobiologists with valuable information and a means of studying neuronal apop- tosis in the nervous system of insects.

Conservation of the egg-laying hormone neuropeptide and attractin pheromone in the spotted sea hare, Aplysia dactylomela

In the marine opisthobranch mollusc, Aplysia, secreted peptides and proteins play an essential role in egg laying and mate attraction. Aplysia californica egg laying is initiated by secretion of the egg-laying hormone (ELH) peptide while mate attraction is made possible by protein pheromones, such as attractin, released into the surrounding seawater with the egg cordon. In this study, we investigated the existence of similar egg-laying hormone and attractin products in the spotted sea hare, Aplysia dactylomela, a species that is widely distributed in almost all tropical and temperate oceans, including Australia's Great Barrier Reef. Immunological analysis revealed that an ELH-like transmitter is present within bag cell somata and processes of the abdominal ganglion. A molecular genetic approach found that the ELH precursor mRNA is synthesized in the abdominal ganglia and encodes a 36-residue peptide (dELH) that is cleaved from the prohormone prior to secretion. It is most closely related to A. californica and A. brasiliana ELH (91.7% identical). We also found that A. dactylomela synthesize an attractin pheromone in the albumen gland that is released during egg laying. The gene encodes a 58-residue mature protein that is 74.9% similar to A. californica attractin. We demonstrate that an increase in seawater temperature can disrupt attractins higher order interactions, such as those with the pheromone temptin, and accelerates attractin degradation. Together, these findings further expands our understanding of pheromone intermolecular interactions and presents an opportunity for further study of how increases in sea water temperature may affect this important marine communication system.

Gonadotropin-releasing hormone-like molecule is not an acute reproductive activator in the gastropod, Aplysia californica

Gonadotropin-releasing hormone (GnRH) is indispensable for reproductive activation in all vertebrates. Although several GnRH-like molecules have been isolated from non-chordates, the function of GnRH in these taxa remains unclear. We previously isolated the full-length cDNA sequence of a prohormone containing a GnRH-like molecule, termed ap-GnRH, from the gastropod mollusk, Aplysia californica. In this study, we characterized the distribution and quantity of ap-GnRH peptide in several central and peripheral tissues of A. californica. Further, we performed in vivo and in vitro studies to explore the function of ap-GnRH in these animals. Immunohistochemistry and radioimmunoassay using specific antisera against ap-GnRH showed that pedal ganglia contained the highest level of ap-GnRH peptide, followed by cerebral ganglia, abdominal ganglia, and then buccal ganglia. Ovotestis did not contain detectable levels of ap-GnRH peptide. Injection of sexually mature and immature animals with synthetic ap-GnRH over a course of 10–14 days had no effects on ovotestis mass, reproductive tract mass, egg-laying, and penile eversion. ap-GnRH also failed to alter oocyte growth and egg-laying hormone accumulation and secretion. Interestingly, ap-GnRH injection triggered acute behavioral responses including the stimulation of parapodial opening, inhibition of feeding, and promotion of substrate attachment. Our results showed that in A. californica, ap-GnRH could modulate a wide range of behavioral attributes. Most strikingly, ap-GnRH is not involved in the acute activation of reproduction in a fashion similar to vertebrate GnRH.

Sex pheromone composition of the cotton caterpillar, Palpita indica (Lepidoptera: Pyralidae), in Korea

This study was conducted to investigate the sex pheromone composition of Palpita (= Diaphania) indica (Saunders) (Lepidoptera: Pyralidae) in Korea. Two sex pheromone components, E11-16:Al and E,E-10,12-16:Al, were identified by GC and GC-EAD analysis of sex pheromone gland extracts. The mean ratios of the two components, E11-16:Al and E,E-10,12-16:Al, were about 6.5:3.5 and 7.5:2.5 in gland extracts and in SPME collection, respectively. In field bioassays, maximum attraction occurred in traps baited with a 7:3 ratio of E11-16:Al and E,E-10,12-16:Al. The head extracts of P. indica stimulated the sex pheromone production of P. indica, as well as Hez-PBAN and PssPT, indicating that a PBAN-like substance exists in the head extracts of P. indica. Whole-mount immunocytochemistry showed that three groups of neurosecretory cells showed PBAN-like immunoreactivity in the SEG of P. indica. The PBAN-like immunoreactivity connected to the Corpora Cardiaca, a neurohemal organ. Also, PBAN-like immunoreactivity was found in the brain and in the thoracic and third/fourth abdominal ganglia. The addition of sex pheromone components of Peridroma saucia to the sex pheromone of P. indica greatly improved the attraction of P. indica males. The mixing of the sex pheromone components of S. exigua did not significantly increase the catches of P. indica, while the sex pheromone of H. armigera completely inhibited the attractiveness.

Detecting intrinsic scattering changes correlated to neuron action potentials using optical coherence imaging.

We demonstrate how optical coherence imaging techniques can detect intrinsic scattering changes that occur during action potentials in single neurons. Using optical coherence tomography (OCT), an increase in scattering intensity from neurons in the abdominal ganglion of Aplysia californica is observed following electrical stimulation of the connective nerve. In addition, optical coherence microscopy (OCM), with its superior transverse spatial resolution, is used to demonstrate a direct correlation between scattering intensity changes and membrane voltage in single cultured Aplysia bag cell neurons during evoked action potentials. While intrinsic scattering changes are small, OCT and OCM have potential use as tools in neuroscience research for non-invasive and non-contact measurement of neural activity without electrodes or fluorescent dyes. These techniques have many attractive features such as high sensitivity and deep imaging penetration depth, as well as high temporal and spatial resolution. This study demonstrates the first use of OCT and OCM to detect functionally-correlated optical scattering changes in single neurons.

Serotonergic Modulation of Crayfish Hindgut

The crayfish hindgut is a morphologically differentiated tube that varies along its length in the distribution of muscles and glands, contractile properties, serotonergic innervation, patterns of 5-HT receptor expression, and sensitivity to serotonin (5-HT). Anatomical differences divide the hindgut into five distinct segments along its length. Spontaneous pulsatile contractions produced by the isolated hindgut decrease in force and increase in frequency along the anterior-posterior axis. Central input to the hindgut comes from a large cluster of 5-HT-immunoreactive neurons in the terminal abdominal ganglion that form a large nerve plexus on the hindgut. 5-HT(1alpha) and 5-HT(2beta) receptors vary in their distribution along the hindgut, and are associated with longitudinal and circular muscles and with axon collaterals of the 5-HT-immunoreactive neurons. Application of 30 nmol l(-1) to 1 mumol l(-1) 5-HT to rostral, middle, or caudal sections of hindgut produced tension changes that varied with the concentration and section. 5-HT also initiated antiperistaltic waves in the posterior hindgut. These results indicate that 5-HT is an important neuromodulator for initiating contractions and coordinating activity in the different functional compartments along the rostral-to-caudal axis of the hindgut.

Distribution of dopamine and octopamine in the central nervous system and ovary during the ovarian maturation cycle of the giant freshwater prawn, Macrobrachium rosenbergii

Dopamine (DA), octopamine (OA) and serotonin (5-HT) are the key neurotransmitters that control gonadal development in decapod crustaceans. 5-HT stimulates, while DA and OA delay gonadal development in Macrobrachium rosenbergii. In the present study, we have further investigated the distribution patterns of DA and OA in the central nervous system (CNS) and ovary during various stages of the ovarian maturation cycle of this giant freshwater prawn. DA- and OA-immunoreactive neurons and fibers were distributed extensively in several regions of the brain, subesophageal ganglion (SEG), thoracic ganglia and abdominal ganglia. In the brain, the two neurotransmitters were present in neurons of clusters 6, 7, 11, 17, and nearby neuropil regions. In the SEG, thoracic ganglia and abdominal ganglia, immunoreactive neurons and fibers were found along the midline and in several neuronal clusters around each neuropil region. Staining for DA and OA was more intense in the thoracic ganglia than in other parts of the CNS. In the ovary, DA- and OA-immunoreactivities were present at high intensity in early oocytes. The presence of DA- and OA-immunoreactivities in neural ganglia as well as ovary suggests that DA and OA may also be involved in the reproductive process, particularly ovarian development and differentiation of oocytes in this species.