Nerve endings isolated from chick embryonic optic tectum. 2. Developmental aspects of synaptosomal membrane

Summary Fractions enriched in nerve endings (synaptosomes) have been isolated from chick embryonic optic tectum during development. After osmotic shock, these fractions appeared to be enriched in membranes which during development acquire typical features of mature synaptosomal membranes.     

Modifications ultrastructurelles provoquées par quelques médicaments sur les terminaisons nerveuses adrénergiques et sur la médullaire surrénale

Summary It has been shown that reserpine and guanethidine deplete granules containing catecholamine in sympathetic nerve endings of both the pineal gland and the vas deferens. This effect is blocked by iproniazid. Bretylium is not able to deplete these granules but it modifies their aspect. It has also been observed that granules of the adrenal medulla are depleted less easily than those of sympathetic nerve endings.     

Destruction of afferent nerve terminals in the inner ear of frog by aminooxyactic acid.

The drug aminooxyacetic acid, which inhibits GABA-transaminase, destroys the afferent nerve ending in the inner ear of the frog. The efferent nerve endings and the sensory cells are not affected.     

Studies on the cytochemical localization of adenylate-cyclase activity in Dugesia lugubris s.I.

The localization of adenylate-cyclase activity in Dugesia lugubris s.1. has been investigated cytochemically using 5'-adenylyl-imidodiphosphate as substrate. The enzyme was localized in mucous gland cells, in rhabdite cells, in intercellular spaces and also in nerve endings of this planarian. The presence of adenylate-cyclase on the membrane suggests that it might mediate different stimulus-secretion coupling by increasing cyclic AMP synthesis in specialized areas of the planarian.     

Localization of substance P-immunoreactive nerve fibers in the human digital skin

Substance P-immunoreactive nerve endings were localized in human digital skin by the use of indirect immunohistochemical technique. It was found that substance P-like immunoreactivity was present in free nerve endings in the dermal papillae and in the epidermis. Some Meissner's corpuscles also contained substance P positive nerve endings. Furthermore, substance P-immunoreactive nerves were localized in close connection to sweat gland ducts and blood vessels. The functional significance of these findings was discussed with regard to pain mediation and inflammatory response.     

Destruction of afferent nerve terminals in the inner ear of frog by aminooxyacetic acid

Summary The drug aminooxyacetic acid, which inhibits GABA-transaminase, destroys the afferent nerve endings in the inner ear of the frog. The efferent nerve endings and the sensory cells are not affected.     

Modulator role of prostaglandins (Pg) in adrenergic neurotransmission in carotid sinus]

In Rabbit carotid sinus, the presence of sympathetic nerve endings capable of releasing noradrenaline has been demonstrated. The release of NA in response to sympathetic nerve stimulation was decreased by PgE2 and a precursor of Pg (arachidonic acid) but was strongly increased by an inhibitor of Pg biosynthesis (indomethacin). The experiments carried out demonstrated that freshly synthesized Pg acts in the same way as exogenous Pg and suggested that Pg could have a regulating effect on adrenergic neurotransmission in carotid sinus. The role of this regulating mechanism in the physiology of carotid sinus has been discussed.     

Ultrastructural evidence of a secretory process in the rat pineal gland.

Pericapillar spaces of the rat pineal gland belong to the most active sites of this organ. Neighborhood of sympathetic nerve endings, capillaries and pinealocyte processes facilitates possibly the synthesis and the secretion of methoxyindoles. Lipid droplets migrate through the pinealocyte cellular processes towards the terminal enlargement or poles, where they are secreted into the pericapillar space, and the possibility that indoleamines are included in the lipid droplets has been discussed.     

Innervation of the ovarian interstitial cell of the chick embryo.

Electron microscopic examination of the developing ovary of 15-20-day chick embryos revealed that the interstital cells well innervated. Nerve fibres and nerve endings were observed in close contact with steroid-producing cells.     

Peptidergic innervation of the temporomandibular disk in the rat

Summary The peptidergic innervation of the temporomandibular disk was investigated in the postnatal young rat by using an indirect immunofluorescence method. Calcitonin gene-related peptide-containing nerve fibers were located around the blood vessels and terminated as free nerve endings in the disk. These nerve fibers may be of a sensory nature.     

Peptidergic innervation of the temporomandibular disk in the rat

The peptidergic innervation of the temporomandibular disk was investigated in the postnatal young rat by using an indirect immunofluorescence method. Calcitonin gene-related peptide-containing nerve fibers were located around the blood vessels and terminated as free nerve endings in the disk. These nerve fibers may be of a sensory nature.     

Central terminals of capsaicin-sensitive primary afferent make synaptic contacts with neuronal soma in the mouse substantia gelatinosa

Degeneration of primary afferent central terminals (C-terminals) that contact neuronal soma in the substantia gelatinosa of the spinal dorsal horn was examined by electron microscopy 2 h after s.c. injection of capsaicin into newborn and adult mice. The C-terminals were small, dark, sinuous or slender terminals with clear synaptic vesicles in the early postnatal period. They are thought to develop into scalloped CI-terminals, surrounded by dendrites and a few axonal endings, forming synaptic glomeruli. The same type of nonglomerular terminals making presynaptic contacts with neuronal soma showed degeneration in both the newborn and adult animals, and were identified as capsaicin-sensitive CI-terminals. This finding suggests that capsaicin-sensitive C-fibers have a modulatory role on their own nociceptive input besides functioning in nociceptive transmission in the substantia gelatinosa.     

Studies on the cytochemical localization of adenylate-cyclase activity inDugesia lugubris s.l.

Summary The localization of adenylate-cyclase activity inDugesia lugubris s.l. has been investigated cytochemically using 5-adenylyl-imidodiphosphate as substrate. The enzyme was localized in mucous gland cells, in rhabdite cells, in intercellular spaces and also in nerve endings of this planarian. The presence of adenylate-cyclase on the membrane suggests that it might mediate different stimulus-secretion coupling by increasing cyclic AMP synthesis in specialized areas of the planarian.Supported in part by a grant from Consiglio Nazionale delle Ricerche, Rome.Acknowledgments. This work was performed with the technical assistence of the laboratory of Electron Microscopy of the University of Perugia.     

The neurosecretory system of the octopus vena cava: A neurohemal organ

Summary Endings of about two million small neurones form a voluminous neuropil inside the vena cava of cephalopods, in direct contact with the blood. These nerve endings are filled with masses of typical neurosecretory granules. By immunocytochemistry we could distinguish three different populations of secretory endings in the vena cava neuropil ofOctopus vulgaris: 1) a population of endings which were immunoreactive with antibodies against the pentapeptide proctolin; 2) a population with oxytocin/vasopressin- and neurophysin-like immunoreactivity; 3) a population immunoreactive with antibodies which were raised against the molluscan cardioexcitatory peptide Phe-Met-Arg-Phe-amide, against -melanotropin, and against atriopeptin. Extracts of the octopus vena cava stimulated amplitude and frequency of the isolated octopus heart preparation. Similar effects were exerted by peptides with the C-terminal structure-Arg-Phe-amide. Recently, we could isolate and identify in vena cava extracts four peptides; Phe-Met-Arg-Phe-amide, Phe-Leu-Arg-Phe-amide, Ala-Phe-Leu-Arg-Phe-amide and Thr-Phe-Leu-Arg-Phe-amide. Other peptides have not yet been identified. The fact that the peptides against which the immunoreactive antibodies were raised affected, in different organisms, blood volume, blood pressure, renal function and heart contraction suggests that one of the main functions of the neurosecretory system of the vena cava is a hormonal control of circulation.     

Multiple Innervation von Muskelfasern imM. vocalis des Menschen

Summary In contrast to the narrow terminal innervation bands of human skeletal muscles, the vocal muscle shows a particularly extended region of synaptic contacts. A great number of muscle fibres receive two or more motor endings forming individual endplates at a distance of several hundred micra. The physiological significance would be a more rapid activation.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.

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Frl.Ingeborg Schnöring danke ich für wertvolle techn. Hilfe.     

The intrapulmonary neuroepithelial bodies after vagotomy: demonstration of their sensory neuroreceptor-like innervation

Summary In the neonatal rabbit, infranodosal vagotomy destroys most of the intracorpuscular nerve endings of the pulmonary neuroepithelial bodies (NEB), while supranodosal vagotomy leaves these nerve endings intact. We conclude that NEB are mainly innervated by sensory neurons whose cell bodies lie in the nodose ganglion of the vagus nerve. These findings support the hypothesis that although secretory in nature, NEB are neuroreceptor structures.This study was supported by the Nationaal Fonds voor Wetenschappelijk Onderzoek. Fonds voor Geneeskundig Wetenschappelijk Onderzoek, Belgium. The authors thank R. Renwart and K. Armee for technical, G. Pison for photographical assistance.     

Uptake and transport of exogenous peroxidase in the masticatory muscles of cats. Localization of ganglionic neurons]

Retrograde axonal transport of Horseradish peroxydase (HRP) has been used to trace the cells of origin of proprioceptive fibers in jaw-closing and jaw-opening muscles. After injection of HRP in young cats' masticatory muscles (masseteric, temporal, pterygoid, mylohyoid and digastric) labelled neurons were found in the ipsilateral semi-lunar ganglion and trigeminal mesencephalic nucleus. It is concluded that sensory endings are present in jaw-opening as in jaw-closing muscles; possibly the afferent fibers from muscle endings of the opener muscles have their somata in the mesencephalic nucleus, afferent fibers from tendinous receptors in the semi-lunar ganglion.     

The synapsins: beyond the regulation of neurotransmitter release

The synapsins are a family of five closely related neuron-specific phosphoproteins associated with the membranes of synaptic vesicles. The synapsins have been implicated in the regulation of neurotransmitter release. They tether synaptic vesicles to actin filaments in a phosphorylation-dependent manner, controlling the number of vesicles available for release at the nerve terminus. A growing body of evidence suggests that the synapsins play a broad role during neuronal development. They participate in the formation and maintenance of synaptic contacts among central neurons. In addition, each synapsin has a specific role during the elongation of undifferentiated processes and their posterior differentiation into axons and dendrites. In this review, we focus on these novel roles of synapsins during the early stages of development. Received 26 September 2001; received after revision 8 November 2001; accepted 9 November 2001     

Innervation of the ovarian interstitial cell of the chick embryo

Summary Electron microscopic examination of the developing ovary of 15–20-day chick embryos revealed that the interstitial cells were well innervated. Nerve fibres and nerve endings were observed in close contact with steroid-producing cells.     

Neocortical transplants in the rat brain: an ultrastructural study

Electron microscopic analysis of neocortical transplants in the cerebellum of the host animals showed that the nerve cells, glial cells, and neuropil of the transplants were normal. These transplants showed anatomical integration with the host brain through various regions of interface. Neuropil interfaces were found to have a high density of synaptic profiles, and medullary interfaces had a very small number of synaptic profiles.