Tryptophanyl-tRNA synthetase-like immunoreactivity in the central nervous system and midgut of the migratory locust. Comparisons with gastrin-cholecystokinin-like and octopamine-like immunoreactivity.

A tryptophanyl-tRNA synthetase (TrpRS)-immunoreactivity is localized in various neurosecretory cells of all ganglia of the central nervous system of the Orthoptera Locusta migratoria, except in deutocerebrum, and in endocrine cells of the midgut. It has been observed that TrpRS-like material never co-localizes either with CCK-like or octopamine-like material. TrpRS immunoreactive perikarya and processes that ramify extensively throughout the neuropiles have been detected in the protocerebrum, optic lobes, tritocerebrum, suboesophageal, thoracic and abdominal ganglia. In the lateral protocerebrum, a particular TrpRS pathway different from the lateral gastrin cholecystokinin (CCK-8(s] pathway is revealed, certain of these processes terminating in the glandular part of the corpora cardiaca. In the metathoracic ganglion, have been observed numerous immunoreactive cell bodies and processes in the neuropiles. Some of them constitute a major pathway and which are distinct from octopamine (OA) cells but in close vicinity with the latter. In the midgut immunopositive TrpRS-like cells are dispersed among the regenerative and digestive cells of the epithelium; they are different from gastrin-cholecystokinin positive cells. The various TrpRS-like immunoreactivities identified in Locusta indicate that TrpRS-like material may occur in different tissues of organisms other than Vertebrates. These results suggest also that TrpRS-like enzyme could be involved in functions other than aminoacylation, as in Vertebrates.

Immunocytochemical localization of acetylcholine receptors in locust brain using auto-anti-idiotypic acetylcholine antibodies.

Auto-anti-idiotypic antibodies have been detected in antisera of rabbits immunized with an acetylcholine (ACh) conjugate. These antibodies were found to bind to ACh receptor (ACh-R) purified from different species membranes. They competed with the ACh-R antagonist alpha-bungarotoxin and some agonists such as ACh conjugate and ACh itself. They did not recognize acetylcholinesterase. Their characterization 'in vitro' suggested their employment as an immunohistological marker for ACh-R. In the locust brain, specific immunoreactivity was found in neuropils of the protocerebrum, the optic lobes, the deutocerebrum and the tritocerebrum.

Anti-acetylcholine antibodies and the pathogenesis of myasthenia gravis.

Using an ELISA system, antibodies recognizing conjugated acetylcholine (ACh) were detected in sera of patients suffering from myasthenia gravis. The mean antibody level was three times higher in sera from myasthenic than from control patients. No correlation was found between anti-ACh antibody levels and anti-ACh receptor (AChR) titer. Also, the anti-ACh antibody titers were independent of sex and age of patients. Competition experiments demonstrated that the most immunoreactive compounds were choline-glutaryl-bovine serum albumin (BSA) and choline-succinyl-BSA. Antibodies present in the sera of myasthenic patients recognized an antigenic determinant mimicking conjugated ACh. The antibody affinity and specificity were sufficiently high for the detection of ACh in locust brain.

Anti-acetylcholine antibodies and first immunocytochemical application in insect brain.

A specific immunological approach was developed to enable acetylcholine (ACh) to be visualized in biological tissues. A variety of ACh-like immunogens were synthesized, and injected into rabbits. Antibody specificity was tested using an enzyme-linked immunosorbent assay (ELISA) method. The most immunoreactive ACh derivative was found to be choline-glutaryl-lysine. A mixture of allyl alcohol and formaldehyde was found to be the best fixative of ACh in tissues. The specificity of this antibody recognition was tested in vitro and in immunochemistry. There was excellent agreement between the in vitro results and the ACh staining. Moreover, visualization using these anti-ACh antibodies appeared identical to the results using anti-choline acetyltransferase antibodies.

Immunohistochemical localization of dopamine in the brain of the insect Locusta migratoria migratorioides in comparison with the catecholamine distribution determined by the histofluorescence technique.

As part of a follow-up study to our previous investigation of the catecholaminergic neurosecretory cells in the brain of adult female locusts (Locusta migratoria migratorioides) by means of the formaldehyde-induced fluorescence method, we have attempted to specify the identity of the amines present in these cells by an immunohistological technique. Using a recently developed anti-dopamine serum, we have demonstrated that the majority of the catecholaminergic median neurosecretory cells contain dopamine. Moreover, dopamine is present in some cell bodies of other zones of the brain, i.e. the median subocellar neurosecretory cells, perikarya in external areas of the protocerebrum, below the calyces, around the pedunculus, in the optic lobes (between the lobula and the medulla, between the medulla and the lamina), and in external zones of the tritocerebrum. Among the structured neuropils, which were particularly fluorescent in the formaldehyde-induced fluorescence method, only the pedunculus, the posterior part of the central body, the external zones of the alpha- and beta lobes and the proximal part of the lamina contain little dopamine.

[Histochemical fluorescence study of aminergic cells throughout the central nervous system of the migratory locust (author's transl)]. / Etude en histofluorescence de cellules aminergiques dans le systeme nerveux central du criquet migrateur.

We have investigated the aminergic neurosecretory cells in the brain and the ganglia of the ventral nerve cord of the adult female locust, by means of the Falck and Hillarp method, with or without a block of the degradation of amines by nialamide. In the brain, we have confirmed the presence of catecholamines and probably indolamines-containing cells and defined their positions in the protocerebrum and the lateral zones of the deutocerebrum and the tritocerebrum. In the ventral cord, we have found groups of catecholaminergic cell bodies in suboesophageal, thoracic and abdominal ganglia, and probably indolaminergic cell bodies in thoracic and some abdominal ganglia. Aminergic fibres are present in all the ventral cord. They are especially numerous in suboesophageal and thoracic ganglia. In these ganglia, some fibres enter the roots of some somatic nerves.