Localization of Lom-AG-myotropin I-like substances in the male reproductive and nervous tissue of the locust,Locusta migratoria

Summary Lom-AG myotropin I (Lom-AG-MTI) was the first peptide to be isolated from the male accessory reproductive glands of the locust, Locust migratoria. It shows no sequence similarity to any of the peptides identified from vertebrate or invertebrate tissues. A polyclonal antiserum was used to localize Lom-AG-MTI-like material in the male reproductive system and nervous system of the locust. Immunoreactivity was found in two of the hyaline gland tubules. In the brain, cell bodies were detected in the proto- and deuterocerebrum as well as the frontal ganglion. Nerve fibers were stained in the neuropils of the brain and throughout the labial nerves into the recurrent nerve. Thoracic and last abdominal ganglia contained neurons which could be stained with Lom-AG-MTI antiserum. The pronounced reactivity in the central nervous system suggests a possible neuroregulatory function of the peptide.     

Immunocytochemical demonstration of octopamine-immunoreactive cells in the nervous system of Locusta migratoria and Schistocerca gregaria

Summary The distribution of octopamine in the metathoracic ganglion, brain and corpus cardiacum of Locusta migratoria and Schistocerca gregaria was investigated by means of immunocytochemistry with an antiserum against octopamine. The dorsal unpaired median (DUM) cells of the metathoracic ganglion were found to be strongly octopamine-immunoreactive. In the rostroventral part of the protocerebrum a group of seven immunopositive cells was demonstrated. Stained nerve fibres of these cells run into three directions: circumoesophageal connectives, midbrain, and optic lobes. As far as the protocerebrum is concerned, immunoreactive fibres were found in the central body, the protocerebral bridge, and in other neuropile areas. In the optic lobe a dense plexus of immunopositive fibres was found in the lobula and in the medulla. In the brain one other immunopositive cell was demonstrated, situated at the lateral border of the tritocerebrum. Octopamine could not be shown to occur either in the globuli cells of the mushroom bodies or in the dorsolateral part of the protocerebrum, where the perikarya of the secretomotor neurones are located that innervate the glandular cells of the corpus cardiacum. In the nervi corporis cardiaci II, which contain the axons of the neurones that extend into the glandular part of the corpus cardiacum, and in the corpus cardiacum proper no specific octopamine immunoreactivity could be found.     

Locustatachykinin III and IV: two additional insect neuropeptides with homology to peptides of the vertebrate tachykinin family

Two myotropic peptides termed locustatachykinin III and IV were isolated from 9000 brain-corpora cardiaca-corpora allata-suboesophageal ganglion extracts of the locust, Locusta migratoria. The primary structures of Lom-TK III and IV were established as amidated decapeptides: Ala-Pro-Gln-Ala-Gly-Phe-Tyr-Gly-Val-Arg-NH2 (Lom-TK III) and Ala-Pro-Ser-Leu-Gly-Phe-His-Gly-Val-Arg-NH2 (Lom-TK IV). The locustatachykinins were synthesized and shown to have chromatographic and biological properties identical with those of the native materials. They stimulate visceral muscle contractions of the oviduct and the foregut of Locusta migratoria and of the hindgut of Leucophaea maderae. Both peptides exhibit sequence homologies with the vertebrate tachykinins. Sequence similarity is greater with the fish and amphibian tachykinins (up to 40%) than with the mammalian tachykinins. In addition, the intestinal and oviducal myotropic activity of the locustatachykinins is analogous to that of vertebrate tachykinins. Both chemical and biological similarities of vertebrate and insect tachykinins substantiates the evidence for a long evolutionary history of the tachykinin peptide family.     

Locustatachykinin I and II, two novel insect neuropeptides with homology to peptides of the vertebrate tachykinin family

Two myotropic peptides termed locustatachykinin I (Gly-Pro-Ser-Gly-Phe-Tyr-Gly-Val-Arg-NH2) and locustatachykinin II (Ala-Pro-Leu-Ser-Gly-Phe-Tyr-Gly-Val-Arg-NH2) were isolated from brain-corpora cardiaca-corpora allata-suboesophageal ganglion extracts of the locust, Locusta migratoria. Both peptides exhibit sequence homologies with the vertebrate tachykinins. Sequence homology is greater with the fish and amphibian tachykinins (up to 45%) than with the mammalian tachykinins. In addition, the intestinal myotropic activity of the locustatachykinins is analogous to that of vertebrate tachykinins. The peptides discovered in this study may just be the first in a whole series of substances from arthropod species to be identified as tachykinin family peptides. Moreover, both chemical and biological similarities of vertebrate and insect tachykinins substantiate the evidence for a long evolutionary history of the tachykinin peptide family.     

Gastrin/cholecystokinin-like immunoreactivity in the nervous system of Aeschna cyanea (Insecta,Odonata)

Summary Gastrin/cholecystokinin (gastrin/CCK)-like immunoreactivity has been detected in the brain, suboesophageal ganglion and corpora cardiaca of the larva of Aeschna cyanea by radioimmunoassay and immunohistochemistry, by use of two antisera raised against the sulfated (CCK-8S) and the unsulfated form (CCK-8NS) of the carboxyl terminal octapeptide. Numerous immunoreactive neurons were demonstrated in the protocerebrum (exclusive of optic lobes) and suboesophageal ganglion where 20 and 15 symmetrical clusters of reactive cells, respectively, were observed. Immunoreactive cells also occurred in the tritocerebrum, the optic lobes and the frontal ganglion. In the corpora cardiaca, gastrin/CCK-like material was found both within intrinsic cells and axon terminals. RIA measurements support the immunohistochemical results in so far as large amounts of gastrin/CCK-like material were detected in the brain, corpora cardiaca and suboesophageal ganglion complex. Both boiling water-acetic acid- and methanol-extraction procedures were performed. Comparisons of the results lead to the conclusion that a large part of the gastrin/CCK-like material occurs as small molecules. Immunohistochemical procedures performed on material fixed in a solution of picric acid-paraformaldehyde demonstrated differences in the immunoreactivity of the tested antisera. First, the immunohistochemical reaction was always more pronounced when the CCK-8NS antiserum was used instead of the CCK-8S antiserum, which may be interpreted by a lower affinity of the latter. In the second place, some neurons strongly stained by the CCK-8NS antiserum were only very faintly if at all stained by the CCK-8S antiserum, which may mean that different peptides or at least distinct forms of the same precursor are detected.     

Leucokinin and callitachykinin immunoreactive neurons during postembryonic development of calliphora vomitoria (L.) (DIPTERA : CALLIPHORIDAE)

Neurons containing 2 types of myotropic neuropeptides were investigated by immunocytochemistry during postembryonic development of the brain and ventral nerve cord of the blowfly Calliphora vomitoria (Diptera : Calliphoridae). Antisera raised against the insect neuropeptides Callitachykinin II (CavTK II), Locustatachykinin I (LomTK I), and Leucokinin I (LK I) were used. Callitachykinin immunoreactive (CavTK–IR) neurons were detected from the 1st-instar larva throughout development to adult. The number of CavTK–IR cell bodies in the brain was 4–16 in larval stages, 10–84 in pupal stages, and over 140 neurons in the newly emerged fly. With the CavTK antiserum, the fibers of only 4 descending neurons were detected in thoracico–abdominal ganglia throughout development. The antiserum to LomTK displayed the same neurons as that to CavTK II as well as a small number of additional neurons. Notably, there were seen about 14–20 locustatachykinin-like immunoreactive (LomTK-LI) cell bodies in the thoracico–abdominal ganglia throughout development. Leucokinin-like immunoreactive (LK-LI) neurons were labeled throughout postembryonic development. In the brain, 2–4 LK-LI cell bodies were labeled from 1st-instar larva to 8-day-old pupa, and 6 LK-LI cell bodies were labeled in the adult brain. In the abdominal ganglia, 7 pairs of LK-LI cell bodies were labeled from 1st-instar larva to 96-h-old pupa, 8 pairs in 8-day-old pupa, and 9 pairs in newly emerged fly, respectively. The CavTK containing neurons in the brain displayed a drastic increase in numbers from larval stages to adult, which indicates an addition of functional roles for this type of peptide. During earlier pupal stages, the number of CavTK–IR neurons decreased. The LK-LI neurons, however, were strongly immunoreactive throughout postembryonic development. Only one additional pair of cells appeared in the brain and 2 additional pair of cells appeared in the abdominal ganglia of the adult as compared with larvae. The continuous high expression of LK-LI material may suggest a functional role for this type of peptide during development.     

棉铃虫幼虫脑和咽下神经节的三维结构构建

【目的】解剖棉铃虫Helicoverpa armigera (Hübner) 5龄幼虫脑和咽下神经节及其内部神经髓形态结构,并分析和构建幼虫脑和咽下神经节以及各神经髓的三维结构模型。【方法】采用免疫组织化学方法解剖脑和咽下神经节的内部神经髓结构,利用激光共聚焦显微镜获取脑和咽下神经节扫描图像,然后利用AMIRA 三维图像分析软件进行图像分析,从而构建脑和咽下神经节的三维结构模型,并测量脑和咽下神经节以及内部各神经髓的体积,并分析了相对比例。【结果】 棉铃虫5龄幼虫脑和咽下神经节由围咽神经索连接在一起。脑主要由前脑、中脑和后脑3部分组成。前脑内包括视叶、蕈形体和中央体等形态结构较明显的神经髓。此外,前脑还包括其他位于脑的左右两侧以及背侧和腹侧大量神经髓区域,约占脑总神经髓的59.65%。这些神经髓区域边界不明显。中脑主要包括1对触角叶;后脑位于脑的腹侧和触角叶的下方,体积较小。咽下神经节由3个神经节融合构成,从前到后分别为上颚神经节、下颚神经节和下唇神经节,由于融合的紧密程度高,3个神经节间的边界不明显。【结论】阐明了棉铃虫5龄幼虫脑和咽下神经节的神经髓形态结构,构建了脑和咽下神经节以及内部神经髓的三维结构模型。三维模型可以任意旋转,能从任何角度观察脑、咽下神经节和内部不同神经髓的结构及其它们之间的空间关系。本研究结果对研究棉铃虫脑和咽下神经节信息接收、处理及调控行为的机制奠定了解剖学基础。     

Distribution of tachykinin-related neuropeptide in the developing central nervous system of the moth Spodoptera litura

Neuropeptides with similarities to vertebrate tachykinins, designated tachykinin-related peptides (TRPs), have been identified in several insect species. In this investigation we have utilized an antiserum raised to one of the locust TRPs, locustatachykinin-I (LomTK-I), to determine the distribution pattern of LomTK-like immunoreactive (LTKLI) neurons in the developing nervous system of the moth Spodoptera litura. A number of LTKLI neurons could be followed from the larval to the adult nervous system: a set of median neurosecretory cells (MNCs) in the brain, a pair of brain descending neurons and a few sets on neurons in the ventral nerve cord. The distribution of LTKLI neurons in the adult brain is very similar to that seen in other insect species with prominent arborizations in the central body, antennal lobes, mushroom body calyces, optic lobe neuropils and other distinct neuropil areas in the protocerebrum and tritocerebrum. A new finding is the presence of LTKLI neurosecretory cells with axon terminals in the anterior aorta and corpora cardiaca, suggesting for the first time a neurohormonal role of tachykinin-related peptide(s) in insects. During postembryonic development the number of LTKLI neurons in the ventral nerve cord decreases somewhat, whereas the number increases in the brain. Thus the functional roles of TRPs may change to some extent during development.     

Aminergic neurons in the brain of blowflies and Drosophila: dopamine- and tyrosine hydroxylase-immunoreactive neurons and their relationship with putative histaminergic neurons

Summary The distribution and morphology of neurons reacting with antisera against dopamine (DA), tyrosine hydroxylase (TH) and histamine (HA) were analyzed in the blowflies Calliphora erythrocephala and Phormia terraenovae. TH-immunoreactive (THIR) and HA-immunoreactive (HAIR) neurons were also mapped in the fruitfly Drosophila melanogaster. The antisera against DA and TH specifically labeled the same neurons in the blowflies. About 300 neurons displayed DA immunoreactivity (DAIR) and THIR in the brain and subesophageal ganglion of the blowflies. Most of these neurons were located in bilateral clusters; some were distributed as bilateral pairs, and two ventral unpaired median (VUM) neurons were seen in the subesophageal ganglion. Immunoreactive processes were found in all compartments of the mushroom bodies except the calyces, in all divisions of the central body complex, in the medulla, lobula and lobula plate of the optic lobe, and in non-glomerular neuropil of protocerebrum, tritocerebrum and the subesophageal ganglion. No DA or TH immunoreactivity was seen in the antennal lobes. In Drosophila, neurons homologous to the blowfly neurons were detected with the TH antiserum. In Phormia and Drosophila, 18 HA-immunoreactive neurons were located in the protocerebrum and 2 in the subesophageal ganglion. The HAIR neurons arborized extensively, but except for processes in the lobula, all HAIR processes were seen in non-glomerular neuropil. The deuto- and tritocerebrum was devoid of HAIR processes. Double labeling experiments demonstrated that TH and HA immunoreactivity was not colocalized in any neuron. In some regions there wasm however, substantial superposition between the two systems. The morphology of the extensively arborizing aminergic neurons described suggests that they have modulatory functions in the brain and subesophageal ganglion.     

Crustacean cardioactive peptide-immunoreactive neurons innervating brain neuropils,retrocerebral complex and stomatogastric nervous system of the locust,Locusta migratoria

The distribution and morphology of crustacean cardioactive peptide-immunoreactive neurons in the brain of the locust Locusta migratoria has been determined. Of more than 500 immunoreactive neurons in total, about 380 are interneurons in the optic lobes. These neurons invade several layers of the medulla and distal parts of the lobula. In addition, a small group of neurons projects into the accessory medulla, the lamina, and to several areas in the median protocerebrum. In the midbrain, 12 groups or individual neurons have been reconstructed. Four groups innervate areas of the superior lateral and ventral lateral protocerebrum and the lateral horn. Two cell groups have bilateral arborizations anterior and posterior to the central body or in the superior median protocerebrum. Ramifications in subunits of the central body and in the lateral and the median accessory lobes arise from four additional cell groups. Two local interneurons innervate the antennal lobe. A tritocerebral cell projects contralaterally into the frontal ganglion and appears to give rise to fibers in the recurrent nerve, and in the hypocerebral and ingluvial ganglia. Varicose fibers in the nervi corporis cardiaci III and the corpora cardiaca, and terminals on pharyngeal dilator muscles arise from two subesophageal neurons. Some of the locust neurons closely resemble immunopositive neurons in a beetle and a moth. Our results suggest that the peptide may be (1) a modulatory substance produced by many brain interneurons, and (2) a neurohormone released from subesophageal neurosecretory cells.     

Tachykinin-related neuropeptide in the crayfish olfactory midbrain

Immunoreactivity indicative of tachykinin-related peptide (TRP) was detected in the olfactory midbrain of the crayfish Pacifastacus leniusculus when using an antiserum to the insect neuropeptide locustatachykinin I (LomTK-I). A monoclonal antibody to the mammalian tachykinin substance P was shown in double-labeling experiments to label structures in the crayfish brain identical to those labeled with the LomTK antiserum. Within the midbrain LomTK-like immunoreactive (LomTK-LI) material was observed in a limited population of neuronal somata and their varicose processes. A single pair of large interneurons gave rise to numerous varicose LomTK-LI processes innervating a cluster of cell bodies (cluster 10) as well as the olfactory neuropils. The latter neuropil was also innervated by a population of LomTK-LI globuli cells with cell bodies in cluster 9. Radioimmunoassay (RIA), utilizing the LomTK antiserum, and reverse-phase high-performance liquid chromatography (HPLC) were used to partially characterize the immunoreactive material in extract of the portion of the midbrain that houses the olfactory (OL) and accessory (AL) lobes and cell clusters 9 and 10 on the one hand, and in extract of the remaining parts of the brain on the other. Approximately the same amounts of LomTK-LI material were observed for the two extracts. RIA showed that the immunoreactive material of both extracts diluted roughly in parallel to synthetic LomTK-I and HPLC analysis of the extracts revealed immunoreactive material in both tissues which eluted with retention times in the range of synthetic LomTK-I and LomTK-II. These results suggest that TRPs similar to LomTKs are present in the olfactory midbrain of Pacifastacus. The distribution of immunolabeled neuronal structures suggests that in the crayfish, peptide(s) closely related to insect TRPs may act as a neuroactive substance released from nerve fibers in olfactory neuropil areas and at certain neuronal cell bodies.     

Immunocytochemical demonstration of S-antigen (arrestin) in the brain of the blowfly Calliphora vicina

S-Antigen (arrestin)-immunoreaction can be considered as a marker for retinal and extraretinal photoreceptors in both vertebrate and invertebrate species. The present immunocytochemical study with the blowfly Calliphora vicina revealed S-antigen immunoreaction in retinal photoreceptors and various groups of neurons bilaterally distributed in the optic lobes and in the proto-, deuto- and tritocerebrum. S-Antigen-immunoreactive processes and terminal formations were found in the lower division of the central body complex and in the neuropil of the mushroom body. Also neuropil regions of the optic lobe, the lamina, medulla and lobula displayed S-antigen-immunoreactive fibers which were arranged in different patterns. These immunocytochemical data suggest that extraocular photoreceptors may be located in various parts of the blowfly brain. They provide a structural basis for further experiments which are needed to identify definitely these elements as extraretinal photoreceptors.     

Restricted occurrence of Locusta migratoria ovary maturing parsin in the brain-corpora cardiaca complex of various insect species

Ovary maturing parsin (OMP) is a gonadotrophic molecule previously isolated from the neurosecretory lobes of the corpora cardiaca of Locusta migratoria (acridian Orthoptera). A polyclonal antiserum directed against the two biologically active domains of the L. migratoria (Lom) OMP was used to investigate the occurrence of Lom OMP-like substances in brain-corpora cardiaca complexes of other insect species. Using immunohistochemistry, specimens of 40 different insect species belonging to 13 insect orders were tested. The Lom OMP-like substance was strictly limited to specimens of insect species belonging to the Acridae. It occurred in non-basophilic cells of the pars intercerebralis that project to the corpora cardiaca, as in Locusta. Although the antiserum only detected Lom OMP-like material in the Acridae, it is possible that related molecules exist in other insects. The antiserum may be very specific for domains of the Lom OMP molecule that have not been highly conserved during evolution or possibly these domains are not accessible to the antiserum in other insects.     

NPY-like peptides occur in the nervous system and midgut of the migratory locust, Locusta migratoria and in the brain of the grey fleshfly, Sarcophaga bullata

The distribution of the NPY-like substances in the nervous system and the midgut of the migratory locust, Locusta migratoria and in the brain of the grey fleshfly, Sarcophaga bullata was determined by immunocytochemistry using an antiserum directed against synthetic porcine NPY. The peroxidase-antiperoxidase procedure revealed that NPY immunoreactive cell bodies and nerve fibers were observed in the brain, optic lobes, corpora cardiaca, suboesophageal ganglion and ventral nerve cord of the locust and in the brain, optic lobes and suboesophageal ganglion of the fleshfly. In the locust midgut, numerous endocrine cells and nerve fibers penetrating the outer musculature contained NPY-like immunoreactivity. The concentrations of NPY immunoreactive material in acetic acid extracts of locust brain, optic lobes, thoracic ganglia, ovaries and midguts was measured using a specific radioimmunoassay technique. The dilution curves of the crude tissue extracts were parallel to the standard curve. The highest amount of NPY-like immunoreactivity was found in the locust ovary and midgut. Reverse-phase high-performance liquid chromatography (RP-HPLC) and radioimmunoassay were used to characterize the NPY-like substances in the locust brain and midgut. HPLC-analysis revealed that NPY-immunoreactivity in the locust brain eluted as three separate peaks. The major peak corresponded to a peptide less hydrophobic than synthetic porcine NPY. RP-HPLC analysis of midgut extracts revealed the presence of an additional NPY-immunoreactive peak which had a retention time similar to the porcine NPY standard. The present data show the existence of a widespread network of NPY immunoreactive neurons in the nervous system of the locust and the fleshfly. Characterization of the immunoreactive substances indicates that peptides similar but not identical to porcine NPY are present in the central nervous system and midgut of insects.     

Insect optic lobe neurons identifiable with monoclonal antibodies to GABA

Five monoclonal antibodies against GABA were tested on glutaraldehyde fixed sections of optic lobes of three insect species, blowflies, houseflies and worker bees. The specificity of these antibodies was analyzed in several tests and compared with commercially available anti-GABA antiserum. A very large number of GABA-like immunoreactive neurons innervate all the neuropil regions of these optic lobes. Immunoreactive processes are found in different layers of the neuropils. The immunoreactive neurons are amacrines and columnar or noncolumnar neurons connecting the optic lobe neuropils. In addition some large immunoreactive neurons connect the optic lobes with centers of the brain. Some neuron types could be matched with neurons previously identified with other methods. The connections of a few of these neuron types are partly known from electron microscopy or electrophysiology and a possible role of GABA in certain neural circuits can be discussed.     

Insect optic lobe neurons identifiable with monoclonal antibodies to GABA

Summary Five monoclonal antibodies aginst GABA were tested on glutaraldehyde fixed sections of optic lobes of three insect species, blowflies, houseflies and worker bees. The specificity of these antibodies was analyzed in several tests and compared with commercially available anti-GABA antiserum.A very large number of GABA-like immunoreactive neurons inncrvate all the neuropil regions of these optic lobes. Immunoreactive processes are found in different layers of the neuropils. The immunoreactive neurons are amacrines and columnar or noncolumnar neurons connecting the optic lobe neuropils. In addition some large immunoreactive neurons connect the optic lobes with centers of the brain.Some neuron types could be matched with neurons previously identified with other methods. The connections of a few of these neuron types are partly known from electron microscopy or electrophysiology and a possible role of GABA in certain neural circuits can be discussed.     

Comparative anatomy of pigment-dispersing hormone-immunoreactive neurons in the brain of orthopteroid insects

Summary In a comparative study, the anatomy of neurons immunoreactive with an antiserum against the crustacean -pigment-dispersing hormone was investigated in the brain of several orthopteroid insects including locusts, crickets, a cockroach, and a phasmid. In all species studied, three groups of neurons with somata in the optic lobes show pigment-dispersing hormone-like immunoreactivity. Additionally, in most species, the tritocerebrum exhibits weak immunoreactive staining originating from ascending fibers, tritocerebral cells, or neurons in the inferior protocerebrum. Two of the three cell groups in the optic lobe have somata at the dorsal and ventral posterior edge of the lamina. These neurons have dense ramifications in the lamina with processes extending into the first optic chiasma and into distal layers of the medulla. Pigment-dispersing hormone-immunoreactive neurons of the third group have somata near the anterior proximal margin of the medulla. These neurons were reconstructed in Schistocerca gregaria, Locusta migratoria, Teleogryllus commodus, Periplaneta americana, and Extatosoma tiaratum. The neurons have wide and divergent arborizations in the medulla, in the lamina, and in several regions of the midbrain, including the superior and inferior lateral protocerebrum and areas between the pedunculi and -lobes of the mushroom bodies. Species-specific differences were found in this third cell group with regard to the number of immunoreactive cells, midbrain arborizations, and contralateral projections, which are especially prominent in the cockroach and virtually absent in crickets. The unusual branching patterns and the special neurochemical phenotype suggest a particular physiological role of these neurons. Their possible function as circadian pacemakers is discussed.     

Serotonin immunoreactive neurons in the central nervous system of an insect (Periplaneta americana)

Serotonin-like immunoreactivity was mapped in the central nervous system (CNS) of the cockroach, Periplaneta americana. Immunoreactive staining occurred in every ganglion of the CNS. The largest numbers of immunoreactive somata were detected in the optic lobes and the brain, and lowest numbers in the first and second thoracic ganglia. Dense stained fibers, ramifications, and varicosities were found in all ganglia, and numerous axon like processes occurred in all interganglionic connectives. Immunoreactive processes were not, however, detected in most of the peripherally projecting nerve roots. Processes were found only in roots of the suboesophageal ganglion and the tritocerebral lobes of the brain. A comparison of the map for serotonin immunoreactivity with one generated for the pentapeptide transmitter proctolin suggests that the two systems overlap only in the suboesophageal ganglion and the tritocerebrum. The amine and peptide may co-occur in neurons in these regions. The serotonin immunoreactive system appeared significantly different from the octopaminergic system of the ventral nerve cord. Seventy-two potentially identifiable immunoreactive cells were located in the cockroach CNS. Some of these may be suitable for physiological study of the functional role of serotonin.     

烟青虫成虫脑结构解剖和三维模型构建

【目的】解剖分析烟青虫 Helicoverpa assulta 成虫脑的结构,并构建脑三维结构数字化模型。【方法】利用神经突触蛋白抗体,对烟青虫成虫脑进行免疫组织化学染色标记,利用共聚焦激光扫描显微镜获得脑扫描数码图像,并结合三维图像分析软件对烟青虫脑结构进行识别分析,构建三维模型。【结果】突触蛋白抗体免疫染色将烟青虫脑和颚神经节的神经髓区域清晰标记出来。烟青虫成虫脑与颚神经节愈合而成为一体,中间具有一个孔洞,为食道穿过的通道。脑主要包括前脑、中脑和后脑3部分。依据染色标记结果识别和构建了至少16个脑神经髓结构。这些神经髓包括边界清晰的视叶、前视结节、蕈形体、中央复合体和触角叶及其亚结构。除此之外,还包括围绕这些神经髓的其他前脑神经髓区域,但这部分前脑神经髓内部边界模糊,不容易细分,而将其与颚神经节区域作为一个整体标记为中间脑,占脑总神经髓的55.05%。【结论】识别出烟青虫脑的主要功能结构区域,并成功构建了三维模型。该研究结果为进一步研究烟青虫脑接收、处理和整合感觉信息及调控行为的机制奠定了解剖学基础,并为研究烟青虫或其他昆虫脑结构发育、变异和重塑提供结构形态和体积大小依据。     

Immunolocalisation of crustacean-SIFamide in the median brain and eyestalk neuropils of the marbled crayfish

Crustacean-SIFamide (GYRKPPFNGSIFamide) is a novel neuropeptide that was recently isolated from crayfish nervous tissue. We mapped the localisation of this peptide in the median brain and eyestalk neuropils of the marbled crayfish (Marmorkrebs), a parthenogenetic crustacean. Our experiments showed that crustacean-SIFamide is strongly expressed in all major compartments of the crayfish brain, including all three optic neuropils, the lateral protocerebrum with the hemiellipsoid body, and the medial protocerebrum with the central complex. These findings imply a role of this peptide in visual processing already at the level of the lamina but also at the level of the deeper relay stations. Immunolabelling is particularly strong in the accessory lobes and the deutocerebral olfactory lobes that receive a chemosensory input from the first antennae. Most cells of the olfactory globular tract, a projection neuron pathway that links deuto- and protocerebrum, are labelled. This pathway plays a central role in conveying tactile and olfactory stimuli to the lateral protocerebrum, where this input converges with optic information. Weak labelling is also present in the tritocerebrum that is associated with the mechanosensory second antennae. Taken together, we suggest an important role of crustacean-SIFamidergic neurons in processing high-order, multimodal input in the crayfish brain.