Regulation of sex pheromone biosynthesis in two noctuid species,S. littoralis and M. brassicae,may involve both PBAN and the ventral nerve cord

In order to understand better the mechanism of regulation of pheromone production in moth species, we performed ELISA analyses to detect and follow pheromone biosynthesis activating neuropeptide-like immunoreactivity (PBAN-IR) in different tissues of the two noctuidae species, Spodoptera littoralis and Mamestra brassicae. Male S. littoralis and both male and female M. brassicae brain-subesophageal ganglion (Br-SEG), corpora cardiaca-corpora allata complex, and terminal abdominal ganglion extracts showed the presence of PBAN-IR during both the photophase and the scotophase. However, PBAN-IR was found only in scotophase in female hemolymph. Analysis of extracts of Br-SEG, terminal abdominal ganglion, and hemolymph after HPLC fractionation showed that the most immunoreactive fraction in all the extracts exhibited the same retention time as Hez-PBAN, suggesting that similar PBAN-like material is present in all these tissues. In vivo studies demonstrated that severing the ventral nerve cord in M. brassicae anterior to the terminal abdominal ganglion impaired normal sex pheromone production by third-scotophase females, as was previously shown in S. littoralis. Additionally, PBAN-IR levels were lower in hemolymph samples obtained at the peak of pheromone production in both S. littoralis and M. brassicae females that had the ventral nerve cord severed compared with sham operated animals. These results, along with earlier reported data, indicate that control of pheromone production in both species may involve both PBAN (or PBAN-like peptides) and the ventral nerve cord and support the hypothesis that a neural input from the ventral nerve cord triggers the release of the pheromonotropic peptide(s) into the hemolymph, which then acts directly on the pheromone gland to stimulate pheromone biosynthesis. Arch. Insect Biochem. Physiol. 37:295–304, 1998. © 1998 Wiley-Liss, Inc.

1 We thank Germán Lázaro for insect rearing.

     

Respiratory nervous activity in the isolated nerve cord of the larval dragonfly, and location of the respiratory oscillator

ABSTRACT. Rhythmic respiratory nerve activity was recorded in the dragonfly larvae, Anax parthenope Julius Brauer (Anisoptera). Alternating expiratory and inspiratory bursts of spikes occurred in abdominal nerve cords isolated from all peripheral connections. These bursts are similar to the activity recorded in semi-intact preparations, suggesting that the respiratory rhythm can be generated without peripheral sensory feedback. Expiratory bursts started and ended at the same time in different segments of semi-intact preparations. When connectives were severed, the nerve cord separated from the last abdominal ganglion did not normally show rhythmic bursts; the last ganglion alone and the nerve cord connected to the last ganglion exhibited the rhythmic bursts. However, in a few cases the nerve cord separated from the last ganglion exhibited the rhythm. The results suggest that the last ganglion contains the main oscillator, but that other weak oscillators occur elsewhere.     

Biogenic amines in newly-ecdysed cockroaches.

1. Simultaneous quantification (HPLC and electrochemical detection) of biological extracts have shown dopamine, N-acetyl dopamine, tryptophan, 5-hydroxytryptamine, a 5-hydroxyindolacetic acid-like substance in nervous tissue and hemolymph of Blaberus craniifer and Periplaneta americana. 2. 5-Hydroxytryptophan was only detected in head and thoraco-abdominal nerve cord. 3. Octopamine, but not N-acetyl-5-HT was quantified in the hemolymph.     

Nerve growth factor-induced stimulation of dorsal root ganglion/spinal cord co-grafts in oculo: enhanced survival and growth of CGRP-immunoreactive sensory neurons

Intraocular co-grafts of rat fetal spinal cord and dorsal root ganglia were used to examine the enhanced survival, growth, and differentiation of sensory neurons by nerve growth factor. E14 lumbar spinal segments were implanted into the anterior eye chamber of capsaicin-pretreated rats. Two weeks later, an E14 dorsal root ganglion was implanted beside the spinal cord graft. Nerve growth factor or vehicle was injected weekly for 4 weeks into the anterior eye chamber. Co-grafts were examined weekly and, at 6 weeks, processed for calcitonin gene-related peptide (CGRP) immunofluorescence. No differences in overall size were determined for the grafts. Co-grafts treated with nerve growth factor contained many more CGRP neurons (19.4 cells/20 microm) that were significantly larger (mean 764 microm2) than neurons from control co-grafts (8.6 cells/20 microm; mean 373 microm2). In co-grafts treated with nerve growth factor, CGRP-immunoreactive fibers were extensive in the dorsal root ganglion, adjacent iris, and spinal cord compared to control co-grafts. A few CGRP-positive motoneurons were observed in the spinal cord, but no differences in number or size of motoneurons were found. The current report demonstrates that spinal cord and dorsal root ganglia can be co-grafted in oculo for long periods of time. Many dorsal root ganglion neurons survive and send peripheral processes into the iris and central processes into the spinal cord under the influence of exogenous nerve growth factor. The intraocular graft paradigm can be of use to further examine the role of neurotrophic factors in regulating or modulating dorsal root ganglion and spinal cord neurons.     

Scanning electron microscope observations on the muscle innervation of Oikopleura dioica fol (appendicularia,tunicata) with notes on the arrangement of connective tissue fibres

Critical point dried and fractured appendicularia of the species Oikopleura dioica have been examined in the scanning electron microscope. The dorsal nerve cord with ganglion cells and peripheral nerve fibres could easily be observed. Thick peripheral nerve fibres leave the nerve cord as bilateral pairs at constant intervals along the tail. Most of these fibres branch from the naked nerve cord, but some evidently originate in ganglion perikarya bulging out from the nerve cord itself. These paired peripheral nerves always have elaborate end-arborizations on the medial surface of the lateral muscle cells. They are accordingly interpreted as motor axons. Some thinner peripheral nerve fibres originate at irregular intervals from both the nerve cord and the ganglion cells. Due to the numerous extracellular fibrils that connect the bilateral layers of the epidermal fins and the muscle cells to each other, these thin nerve fibres can seldom be traced to their termination. A few ones can, however, be traced ventrally between the notochord and the muscle cells and seem to end in singular bulb-like expansions. Clusters of synaptic vesicles are present in transmission electron micrographs of such nerves, and they are accordingly believed to carry efferent impulses. The extracellular fibrils are arranged in a highly ordered pattern with thick bundles crossing the gap between the structures to be interconnected and with numerous radiating insertions on the surface of the tissues.     

The distribution of pheromone-biosynthesis-activating neuropeptide (PBAN) immunoreactivity in the central nervous system of the corn earworm moth,Helicoverpa zea

Summary Production of sex pheromone in several species of moths has been shown to be under the control of a neuropeptide termed pheromone-biosynthesis-activating neuropeptide (PBAN). We have produced an antiserum to PBAN from Helicoverpa zea (Lepidoptera: Noctuidae) and used it to investigate the distribution of immunoreactive peptide in the brain-suboesophageal ganglion complex and its associated neurohemal structures, and the segmental ganglia of the ventral nerve cord. Immunocytochemical methods reveal three clusters of cells along the ventral midline in the suboesophageal ganglion (SOG), one cluster each in the presumptive mandibular (4 cells), maxillary (12–14 cells), and labial neuromeres (4 cells). The proximal neurites of these cells are similar in their dorsal and lateral patterns of projection, indicating a serial homology among the three clusters. Members of the mandibular and maxillary clusters have axons projecting into the maxillary nerve, while two additional pairs of axons from the maxillary cluster project into the ventral nerve cord. Members of the labial cluster project to the retrocerebral complex (corpora cardiaca and cephalic aorta) via the nervus corpus cardiaci III (NCC III). The axons projecting into the ventral nerve cord appear to arborize principally in the dorsolateral region of each segmental ganglion; the terminal abdominal ganglion is distinct in containing an additional ventromedial arborization in the posterior third of the ganglion. Quantification of the extractable immunoreactive peptide in the retrocerebral complex by ELISA indicates that PBAN is gradually depleted during the scotophase, then restored to maximal levels in the photophase. Taken together, our findings provide anatomical evidence for both neurohormonal release of PBAN as well as axonal transport via the ventral nerve cord to release sites within the segmental ganglia.Abbreviations A aorta - Br-SOG brain-suboesophageal ganglion complex - CC corpus cardiacum - PBS phosphate-buffered saline - PLI PBAN-like immunoreactivity - TAG terminal abdominal ganglion - VNC ventral nerve cord     

Location of efferent sympathetic neurons and afferent neurons in spinal ganglia innervating the heart

Location and numbers of neurons associated with sympathetic innervation of the heart within the right stellate and accessory cervical ganglia, the spinal cord, and spinal ganglia were investigated using horseradish peroxidase retrograde axonal transport techniques in cats. The enzyme was applied to central sections of the anastomosis of the stellate ganglion with the vagus nerve, the inferior cardiac nerve, and the vagosympathetic trunk caudal to the anastomosis. Labeled neurons within the stellate ganglion were located close to the point of departure of the nerves and more thinly distributed in the accessory cervical ganglion. A group of labeled cells was found in the anastomosis itself. Preganglionic neurons associated with sympathetic innervation of the heat were detected at segmental levels T₁–T₅ in the spinal cord. Labeled neurons were diffusely located in the spinal ganglia, concentrated mainly at levels T₂–T₄.Medical Institute, Ministry of Public Health of the RSFSR, Yaroslavl'. Translated from Neirofiziologiya, Vol. 21, No. 1, pp. 106–111, January–February, 1989.     

The subgenus Persicargas (Ixodoidea: Argasidae: Argas). 22. The effect of feeding on hormonal control of egg development in Argas (Persicargas) arboreus

The blood-meal is essential to complete ova development by supplying nutrients and by stimulating hormone production in mated female Argas (Persicargas) arboreus. Within 3 days after feeding, the hormone is synthesized in the nerve ganglion and afterward is released into the hemolymph. Isolating the ovaries by ligation from the nerve ganglion during the hormone synthesis period interfered with ova development. Injecting an extract of nerve ganglia from 3-day-fed, mated females and of hemolymph from 4-day-fed, mated females into mated, recently fed females induced the same degree of ova development in their isolated ovaries as in fed, mated control females. Injecting nerve ganglion extract from 3-day-fed, mated females into mated, unfed females did not induce ova development.     

Afferent fibers and sensory ganglion cells within the oculomotor nerve in some mammals and man. I. Anatomical investigations.

The present research shows that sensory ganglion cells are located within the oculomotor nerve of monkeys and man. Furthermore, afferent fibers have been found in the IIIrd nerve of all the animals examined (lamb, pig, cat, dog and monkey). These fibers have their perikarya prevalently in the semilunar ganglion. Their pathway could be studied after section of either the trigeminal ophthalmic branch or of the intracranial portion of the IIIrd nerve. Following these operations, degenerating fibers were found entering the brain stem through the oculomotor nerve. In the brain stem, they were traced through the pons and the medulla and were seen to end in the spinal cord, within the subnucleus gelatinosus of the nucleus caudalis trigemini. Their degenerating endings found in the neuropil of the SG Rolandi, represented peripheral axonal endings of the glomeruli, rather than central axonal endings, as was the case after trigeminal rhizotomy. On the basis of these different degenerating patterns, the conclusion can be reached that the perikarya of the afferent fibers located in the semilunar ganglion represent, in reality, a ganglion of the IIIrd nerve.     

The Larval Nervous System of Polygordius lacteus Scheinder, 1868 (Polygordiidae,Polychaeta): Immunocytochemical Data

The nervous system of the planktotrophic trochophore larva of Polygordius lacteus has been investigated using antibodies to serotonin (5-HT) and the neuropeptide FMRFamide. The apical ganglion contains three 5-HT-ir neurons, many FMRFamide-ir neurons and a tripartate 5-HT-ir and FMRFamide-ir neuropil. A lateral nerve extends from each side of the apical ganglion across the episphere and the ventral hyposphere, where the two nerves combine to form the paired ventral nerve cord. These nerves have both 5-HT-ir and FMRFamide-ir processes. Three circumferential nerves are associated with the ciliary bands: two prototroch and one metatroch nerve. All contain 5-HT-ir and FMRFamide-ir processes. An oral nerve plexus also contain both 5-HT-ir and FMRFamide-ir processes develops from the metatroch nerve, and an esophageal ring of FMRFamide-ir processes develops in later larval stages. In young stages the ventral ganglion contains two 5-HT-ir and two FMRFamide-ir perikarya; during development the ventral ganglion grows caudally and adds additional 5-HR-ir and FMRFamide-ir perikarya. These are the only perikarya that could be found along the lateral nerve and ventral nerve cord. The telotroch nerve develops from the ventral nerve cord. The 5-HT-ir and FMRFamide-ir part of the nervous system is strictly bilateral symmetric. and much of the system (i.e. apical ganglion, lateral nerves ventral nerve cord, dorsal nerve and oral plexus) is retained in the adult.     

Evidence for both humoral and neural regulation of sex pheromone biosynthesis in Spodoptera littoralis

Selected tissues presumably involved in the control of sex pheromone production were analyzed by ELISA for the presence of PBAN-like immunoreactivity (PBAN-IR) in Spodoptera littoralis. The temporal distribution pattern of PBAN-IR in the hemolymph is similar to that of pheromone production in the gland. On the other hand, analysis of the retrocerebral complex, brain-subesophageal ganglion complex, and terminal abdominal ganglion (TAG) revealed similar PBAN-IR levels in both photophase and scotophase periods. Pheromonotropic activity exhibited by both hemolymph and TAG, as determined by a modified in vitro bioassay, agrees with the results of the immunochemical analyses. Severing the ventral nerve cord anterior to the TAG impaired normal sex pheromone production by second-scotophase females. These results are discussed in the context of how sex pheromone biosynthesis is regulated by PBAN in S. littoralis. © 1996 Wiley-Liss, Inc.     

Physiological control of pheromone production in Choristoneura fumiferana and C. rosaceana

The diel periodicity of calling behavior and pheromone production are synchronous in virgin females of both Choristoneura fumiferana and C. rosaceana (Lepidoptera: Tortricidae). Newly emerged females decapitated prior to scotophase produced no or very little pheromone 24 h later. However, injection of PBAN or Br-SEG homogenates, obtained from donors of the same or the other species, stimulated pheromone production to normal levels. Transection of the ventral nerve cord (VNC) or extirpation of the terminal abdominal ganglion (TAG) did not affect pheromone production in control females. Similarly, injections of PBAN or Br-SEG homogenates into decapitated females reactivated pheromone production to normal levels, whether or not the VNC was intact or the TAG present. Furthermore, octopamine was not effective in stimulating pheromone production in decapitated females. Taken together, these results indicate that the regulation of pheromone production is not neurally mediated in either Choristoneura species. However, there was no evidence that hemolymph collected from pheromone-producing females contained pheromonotropic activity. Similarly, isolated glands incubated with PBAN did not produce pheromone. The presence of the bursa copulatrix was required to produce pheromone in both tortricids as production was not restored in decapitated bursa-less females injected with PBAN or a Br-SEG homogenate. However, an extract of the bursa copulatrix did not elicit pheromonotropic activity in decapitated females or incubated glands of either species. The bursa copulatrix is only involved in pheromone production of some species of tortricids but our results do not support the current explanation for such interspecific differences. We postulate that the relative importance of a bursa factor may be related to the evolution of different desaturation systems used for pheromone biosynthesis in the Tortricidae. Arch.     

Axonal transport: a quantitative study of retained and transported protein fraction in the cat

The fast axonal transport of proteins was studied in the cat sciatic nerve after injection of [3H]leucine into the spinal ganglion or the ventral horn of the seventh lumbar segment. The amount of transported proteins after ganglion injection was linearly related to the amount of label present at the ganglion. At variable intervals after ganglion or spinal cord injection, the sciatic nerves were sectioned in some experiments. The transport of proteins continued in the peripheral nerve stump in a wavelike manner, but the advancing wave leaves a labeled trail behind. A fraction of this trail corresponds to proteins moving at slower velocities than the velocity of proteins in the wave front. Another fraction of the trail corresponds to molecules retained by the axons. Each nerve segment of 5 mm in length retains 1.5% of the transported proteins, and the profile of retained proteins along the sciatic nerves follows a single exponential function. From the proportion of retained proteins, the concentration of transported proteins at the terminals of branching axons as a function of the branching ratio was estimated. In the case of motor axons innervating the soleus muscle of the cat, the concentration of recently transported proteins at the nerve terminals would be approximately 0.83% of the proteins leaving the spinal cord. This low concentration of transported proteins at the nerve terminals may explain the lability of neuromuscular synapses when axonal transport is decreased or interrupted.     

Neural control of rhythmic pheromone gland exposure in Utetheisa ornatrix (Lepidoptera: Arctiidae)

The rhythmic exposure of the sex pheromone gland during calling in female Utetheisa ornatrix (L.) (Lepidoptera: Arctiidae) is under neural control. Two lines of evidence support this conclusion. (1) Bisection of the ventral nerve cord of adult females prevented calling while sham-operations had little effect. (2) Brief electrical stimulation of the ventral nerve cord in isolated abdomens elicited extended trains of regularly spaced gland exposures indistinguishable from normal calling behaviour. The coordination of calling behaviour is localized in the terminal abdominal ganglion and the peripheral structures that it innervates. Removal of the corpora allata and corpora cardiaca, neurohaemal organs previously implicated in calling control, did not affect calling behaviour.     

BDNF 和 IL-1α 免疫组织化学阳性细胞在商城肥鲵脊神经节中的表达

采用了组织学和免疫组织化学的方法对商城肥鲵的脊髓和脊神经节的石蜡切片进行了研究。结果显示,商城肥鲵的脊髓可分为灰质和白质;白质外有3层膜包围,由外向内依次是硬脊膜、蛛网膜和软脊膜。常规染色显示脊神经节位于脊神经后根,外包被膜,呈不规则的卵圆形,神经节内的细胞有两种,一种为节细胞,胞体圆形或者卵圆形,大小不等,根据胞体的大小又可分为大脊神经节细胞和小脊神经节细胞;另一种细胞叫做卫星细胞,包裹在脊神经节细胞的周围。BDNF和IL-1α一抗均显示脊神经节细胞呈阳性,卫星细胞呈阴性,前者大神经节细胞阳性明显强于小神经节细胞,后者两种神经节细胞的阳性强度无显著差异。     

Control of pheromone biosynthesis in mated redbanded leafroller moths

Mating in the redbanded leafroller moth, Argyrotaenia velutinana, causes a permanent decline in pheromone titers. Three hours following the termination of mating, phermone titers were significantly decreased from premating levels, and titers remained low for at least four days after mating. Pheromone titers were similar in females that had been decapitated or mated for twenty-four hours. In the redbanded leafroller moth, two peptides control pheromone production. The pheromone biosynthesis activating neuropeptide is produced in the brain and the pheromonotropic bursa peptide is produced in the corpus bursae. Both peptides stimulated pheromone biosynthesis in mated females and extracts prepared from brains and bursae of mated females contained pheromonotropic activity. However, severing the ventral nerve cord before mating prevented the decline in pheromone titer that occurred in mated females. Hemolymph collected during scotophase from mated females did not have pheromonotropic activity, whereas hemolymph collected during scotophase from virgin females contained activity. These results indicate that mating produces a signal sent by the ventral nerve cord to the brain to stop the release of pheromone biosynthesis activating neuropeptide. © 1993 Wiley-Liss, Inc.     

Patterns of serotonin-immunoreactive neurons in the central nervous system of the earthworm Lumbricus terrestris L.

Summary The distribution patterns of serotonin-immunoreactive somata in the cerebral and subpharyngeal ganglion, and in the head and tail ganglia of the nerve cord of Lumbricus terrestris are described from whole-mount preparations. A small number of serotonin-immunoreactive neurons occurs in the cerebral ganglion, in contrast to the large population of serotonin-immunoreactive neurons that exists in all parts of the ventral nerve cord. From the arrangement of serotonin-immunoreactive somata in the subpharyngeal ganglion, we suggest that this ganglion arises from the fusion of two primordial ganglia. In head and tail ganglia, the distribution of serotonin-immunoreactive somata resembles that in midbody segments. Segmental variations in the pattern and number of serotonin-immunoreactive somata in the different body regions are discussed on the background of known developmental mechanisms that result in metameric neuronal populations in annelids and arthropods.Abbreviations CG1, CG2 cerebral soma group 1, 2 - CNS central nervous system - GINs giant interneurons - 5-HT 5-hydroxytryptamine, serotonin - 5-HTi 5-HT-immunoreactive - N side nerve - SG19 subpharyngeal soma group 1–9 - SN segmental nerve     

Control of leech swimming activity by the cephalic ganglia

We investigated the role played by the cephalic nervous system in the control of swimming activity in the leech, Hirudo medicinalis, by comparing swimming activity in isolated leech nerve cords that included the head ganglia (supra- and subesophageal ganglia) with swimming activity in nerve cords from which these ganglia were removed. We found that the presence of these cephalic ganglia had an inhibitory influence on the reliability with which stimulation of peripheral (DP) nerves and intracellular stimulation of swim-initiating neurons initiated and maintained swimming activity. In addition, swimming activity recorded from both oscillator and motor neurons in preparations that included head ganglia frequently exhibited irregular bursting patterns consisting of missed, weak, or sustained bursts. Removal of the two head ganglia as well as the first segmental ganglion eliminated this irregular activity pattern. We also identified a pair of rhythmically active interneurons, SRN1, in the subesophageal ganglion that, when depolarized, could reset the swimming rhythm. Thus the cephalic ganglia and first segmental ganglion of the leech nerve cord are capable of exerting a tonic inhibitory influence as well as a modulatory effect on swimming activity in the segmental nerve cord.     

Similarities and differences in the structure of segmentally homologous neurons that control the hearts in the leech,Hirudo medicinalis

Summary The neural circuit that controls the hearts in the leech comprises an ensemble of synaptically interconnected cardiac motor neurons (HE cells) and cardiac interneurons (HN cells). Both the HE cells and the HN cells constitute segmentally homologous sets. We have investigated the structure of these neurons by iontophoretic injection of Lucifer Yellow dye.Bilateral pairs of HE cells have been identified in segmental ganglia 3–19 of the nerve cord. Their structure was found to be nearly identical from ganglion to ganglion and from animal to animal.Bilateral pairs of HN cells have been identified in segmental ganglia 1–7 of the nerve cord. Their dendritic structure was found to vary from ganglion to ganglion. These segmental differences among HN cells were observed consistently from animal to animal. Some of the segmental differences in HN cell structure correlate with previously described physiological differences.