Ultrastructural changes in the dorsal root ganglia evoked by thalidomide in rabbits

Summary Administration of the teratogenic drug thalidomide to pregnant does produces ultrastructural changes in foetal ganglion cells, Schwann cells and axons in the posterior root ganglia corresponding to forelimb segments deformed by the drug. Ultrasttructural changes in ganglia appear on the 13th day of gestation, i.e., preceding the appearance of limb malformation.This work was supported by a grant from Foundation 41.We are grateful to MissC. Ellis and Mr.P. Westphal for technical assistance.     

Dopamine-containing cells in rabbit nodose ganglia

Summary Microspectrofluorometry of rabbit nodose ganglia exposed to formaldehyde vapor revealed that the intraganglionic fluorescent cells (SIF-cells) contain dopamine.     

Pigment-dispersing hormone in <Emphasis Type="Italic">Daphnia</Emphasis> interneurons,one type homologous to insect clock neurons displaying circadian rhythmicity

We report identification of a beta-type pigment-dispersing hormone (PDH) identical in two water flea species, Daphnia magna and Daphnia pulex. It has been identified by cloning of precursors, chromatographic isolation from tissue extracts followed by immunoassays and de novo-mass spectrometric sequencing. The peptide is restricted to a complex system of distinct interneurons in the brain and visual ganglia, but does not occur in neurosecretory cells projecting to neurohemal organs as in decapod crustaceans. Thirteen neuron types individually identified and reconstructed by immunohistochemistry were almost identical in terms of positions and projection patterns in both species. Several neurons invade and form plexuses in visual ganglia and major brain neuropils including the central body. Five neuron types show contralateral pathways and form plexuses in the lateral, dorsal, or postlateral brain neuropils. Others are local interneurons, and a tritocerebral neuron connects the protocerebrum with the neuropil of the locomotory second antenna. Two visual ganglia neuron types lateral to the medulla closely resemble insect medulla lateral circadian clock neurons containing pigment-dispersing factor based upon positional and projectional criteria. Experiments under 12:12 h light/dark cycles and constant light or darkness conditions showed significant circadian changes in numbers and activities of one type of medulla lateral PDH neuron with an acrophase in the evening. This simple PDH system shows striking homologies to PDH systems in decapod crustaceans and well-known clock neurons in several insects, which suggests evolutionary conservation of an ancient peptidergic interneuronal system that is part of biological clocks.     

The occurrence of small,intensely fluorescent (SIF) cells in human sympathetic ganglia

Summary Small, intensely fluorescent (SIF) cells were found histochemically in lumbar sympathetic ganglia (L2) obtained from sympathectomy of 3 patients suffering from chronic occlusive diseases of leg arteries. 3 types of SIF cells were distinguished. These cells will probably contain dopamine.     

Autoradiographic localization of the uptake of 3H-beta-alanine in rat nervous tissue cultures.

Autoradiographic studies on the uptake of 3H-beta-alanine have shown that, in spinal cord and brain stem cultures, both neurones and glial cells have accumulated the amino acid. In contrast, in cultures of cerebellum and dorsal root ganglia, 3H-beta-alanine was only t aken up by glial elements.     

Quantitative histological study of spinal afferent innervation on the ventral surface of the cat stomach by horseradish peroxidase (HRP) method.

Retrograde axonal transport of horseradish peroxidase (HRP) was applied to the ventral surface of the cat stomach. We investigated the number, size and distribution of HRP-positive cells in spinal ganglia. The unexpected finding was the wide distribution of these cells from T3 down to L3. This would result in a diffuse pattern of referred pain.     

Quantitative histological study of spinal afferent innervation on the ventral surface of the cat stomach by horseradish peroxidase (HRP) method

Summary Retrograde axonal transport of horseradish peroxidase (HRP) was applied to the ventral surface of the cat stomach. We investigated the number, size and distribution of HRP-positive cells in spinal ganglia. The unexpected finding was the wide distribution of these cells from T3 down to L3. This would result in a diffuse pattern of referred pain.     

Impairment of rapid axonal transport and concomitant anomaly of smooth endoplasmic reticulum in acrylamide induced neuropathy]

The axonal transport of proteins was studied by radioautography in preganglionic axons of ciliary ganglia in Leghorn chickens treated by acrylamide. The slow axonal transport of proteins was hardly affected. In contrast, the fast axonal transport was severely impaired. Indeed, radioactive proteins accumulated focally at the periphery of several preterminal axons in regions showing a local disorganization of the smooth endoplasmic reticulum which seemed to be one of the earliest changes induced by acrylamide.     

Nerves and taste-buds degeneration in the cat-fishIctalurus melas

Summary After nerve transection, external taste-buds remain apparently normal for more than 3 weeks, become round, then disappear. Cryonecrosis of the cranial ganglia V and VII induces a loss of polarity of the buds, which, though keeping up their form for 50 and even 150 days, are progressively deprived of sensory cells. This shows a dissociation of the actions of nerve factors.     

Effetto della ouabaina sul tessuto nervoso in coltura in vitro

Summary The addition of 1 · 10^–4 ouabain (strophantin-G), a Na⁺-K⁺-dependent ATP-ase inhibitor, to the cultivating medium of chick embryo spinal ganglia in vitro cultures caused the vacuolization of the cytoplasm of the fibroblast-like cells, but not of the nervous ones, after 6 h of culture, with a maximum after 24 h.     

Gas chromatographic-mass spectrometric identification of epinine in rat superior cervical ganglia and formation in vivo

Summary Epinine was identified in rat superior cervical ganglia by a gas chromatographic-mass spectrometric method. The deuterated methyl group of i.v. administered labeled methionine was incorporated into epinine at a slow rate, although epinephrine-CD₃ was rapidly formed. These results indicated that epinine found in the ganglia is not a precursor of epinephrine.Acknowledgments. We wish to thank Dr Magda Claeys for helpful discussions.     

Substance P-like immunoreactivity in the frog dorsal root ganglia

The distribution of substance P-like immunoreactivity was studied in the thoracic dorsal root ganglia of the frog Rana esculenta by immunohistochemistry. Substance P-like immunoreactivity was contained in approximately 50% of primary sensory neurons. The immunoreactive fibers arising from the cell bodies are collected in small bundles within the ganglia neuropil before entering the central and peripheral roots.     

Caffeine as a psychomotor stimulant: mechanism of action

The popularity of caffeine as a psychoactive drug is due to its stimulant properties, which depend on its ability to reduce adenosine transmission in the brain. Adenosine A₁ and A_2A receptors are expressed in the basal ganglia, a group of structures involved in various aspects of motor control. Caffeine acts as an antagonist to both types of receptors. Increasing evidence indicates that the psychomotor stimulant effect of caffeine is generated by affecting a particular group of projection neurons located in the striatum, the main receiving area of the basal ganglia. These cells express high levels of adenosine A_2A receptors, which are involved in various intracellular processes, including the expression of immediate early genes and regulation of the dopamine- and cyclic AMP-regulated 32-kDa phosphoprotein DARPP-32. The present review focuses on the effects of caffeine on striatal signal transduction and on their involvement in caffeine-mediated motor stimulation.Received 8 July 2003; received after revision 7 September 2003; accepted 6 October 2003     

Substance P-like immunoreactivity in the frog dorsal root ganglia

Summary The distribution of substance P-like immunoreactivity was studied in the thoracic dorsal root ganglia of the frogRana esculenta by immunohistochemistry. Substance P-like immunoreactivity was contained in approximately 50% of primary sensory neurons. The immunoreactive fibers arising from the cell bodies are collected in small bundles within the ganglia neuropil before entering the central and peripheral roots.     

Sympatho-inhibitory mechanisms acting at sympathetic ganglia to attenuate hypothalamic-induced pressor effect in the cat

Summary Pressor and tachycardic effects induced in the cat by stimulation of a lateral hypothalamic (LH) site, are shown to be mediated by sympathetic ganglia nicotinic receptor, and potentiated under atropine methyl nitrate sympathetic ganglia blockage. It is postulated that a sympatho-inhibitory pathway muscarinic ganglionic mechanism, co-activated by the LH stimulation, attenuates the pressor and tachycardic effects, the potentiation presumably being a manifestation of blockage of that mechanism.     

Sympatho-inhibitory mechanisms acting at sympathetic ganglia to attenuate hypothalamic-induced pressor effect in the cat

Pressor and tachycardic effects induced in the cat by stimulation of a lateral hypothalamic (LH) site, are shown to be mediated by sympathetic ganglia nicotinic receptor, and potentiated under atropine methyl nitrate sympathetic ganglia blockage. It is postulated that a sympatho-inhibitory pathway muscarinic ganglionic mechanism, co-activated by the LH stimulation, attenuates the pressor and tachycardic effects, the potentiation presumably being a manifestation of blockage of that mechanism.     

Hypnotic effect of serotonin administered in the vago-aortic afferent pathway

A minute amount of serotonin injected in the nodose ganglion circulation area develops abrupt myosis and general electrocortical synchronization activity in "encéphale isolé" Cat preparation. This hypnogenic effect of serotonin can still be reproduced after transection of vago-aortic nerves caudally to the nodose ganglia. The same injections become ineffective after rostral transection of the same pathway. These results suggest that serotonin may trigger some signs of sleep through peripheric nervous elements in which are probably localized in the nodose ganglia.     

Electrophysiological characteristics ofBombyx mori L. ventral nerve cord (effect of sodium and potassium on the membrane potential)

Summary Na⁺ and K⁺ effects on the resting cellular membrane potential of desheathed ganglia of theBombyx mori L. ventral nerve cord have been studied. The cells are depolarized by high concentrations of external potassium ions in the same way as in vertebrates, mollusca and crustacean cells. The possibility that the behaviour of the resting potential is not only influenced by the potassium equilibrium potential, but also by the conductances to other ions, is discussed.The authors are indebted to Prof V. Capraro, Drs B. Giordana and F. Sacchi for helpful comments and criticism.     

Effects of various media on tissular and cellular structures of the superior cervical ganglion of the rat.

The superior cervical ganglia of the rat have been incubated in vitro for 1 h in basal medium Eagle (BME) with Hanks' salts, BME with Earle's salts, Kreb's solution and NCTC 109 medium. Comparison of the cell areas, established by a semi-automatic quantitative method, shows that the three former induce a 30--35% neuronal retraction, whereas NCTC 109 has no effect. Thus this latter medium seems the best one for studies using incubation of these cells.     

Neuroendocrine control of carbohydrate metabolism in the freshwater bivalve molluscLamellidens marginalis

Summary Blood sugars and foot muscle glycogen were measured in the mussel,L. marginalis after ablation of the cerebral ganglia, and in mussels injected with cerebral ganglionic extract 3 h after ablation. There is a rise in the blood sugar and decrease in foot muscle glycogen 3 h after operation, but no change in sham-operated controls. The effect of ablation is reversed by injecting brain extract into ablated mussels. No such effect could be seen in the controls. The results are suggestive of the presence, in the cerebral ganglia, of a hypoglycaemic factor similar to insulin.