Uptake of L-glutamate and L-aspartate in neurones and glial cells of cultured human and rat spinal cord.

Autoradiographic investigations on the uptake of L-glutamate and L-aspartate have shown that the amino acids were taken up by neurones as well as by glial cells of cultured human and rat spinal cord. The activity of glutamate and aspartate varied considerably between individual neurones, whereas glial cells showed a more even distribution of the labelled amino acids. Our results suggest that both neurones and glial cells are involved in the uptake of amino acid transmitters.     

Uptake ofl-glutamate andl-aspartate in neurones and glial cells of cultured human and rat spinal cord

Summary Autoradiographic investigations on the uptake ofl-glutamate andl-aspartate have shown that the amino acids were taken up by neurones as well as by glial cells of cultured human and rat spinal cord. The activity of glutamate and aspartate varied considerably between individual neurones, whereas glial cells showed a more even distribution of the labelled amino acids. Our results suggest that both neurones and glial cells are involved in the uptake of amino acid transmitters.     

Localization of biogenic amines in the central nervous system of Crepidula fornicata (Phil.), Mollusca, Gastropoda, Prosobrancha]

Two categories of neurones at least can be demonstrated in Crepidula fornicata, some containing catecholamines (DA) others indolamines (5 HT). These cells, which are well localized, are often close to azanophilous neurosecretory cells but nevertheless distinct from the latter.     

Ba++ induced square-shaped potential waves in molluscan neurones

Summary Rhythmic slow square-shaped potential waves lasting 20–50 sec are induced in Aplysia neurones when Ca⁺⁺ is replaced by Ba⁺⁺. During the plateau, the membrane is highly permeable to Ba⁺⁺ ions, whereas in the inter-wave period the membrane resistance increases by 60 times. Analysis with slow current ramps suggests that the membrane properties of Ba-treated neurones and normally burst-generating neurones are similar.     

Paraventricular neurones in the rat hypothalamic slice: Lucifer Yellow injection and immunocytochemical identification

Summary Intracellular records were obtained from paraventricular neurones injected with Lucifer Yellow in slices from the rat hypothalamus. Slices containing fluorescent neurones were then serially cut and alternating sections were stained immunocytochemically for vasopressin or oxytocin. Double-labelled cells were found which fluoresced and which had reacted with either vasopressin, or oxytocin antiserum.This study was supported in part by grant 3.469.79 from the Swiss National Science Foundation.     

The action of substance P on mesencephalic reticular and substantia nigral neurones of the rat

Summary Extracellular recordings were made from neurones in the mesencephalic reticular formation and substantia nigra of the rat which was anaesthetized with urethane 1.5–2 g/kg i.p. Out of 44 cells tested 42 were excited by Substance P applied iontophoretically and in some cases this excitation was rapid. Evidence is presented for Substance P as a putative excitatory transmitter onto reticular and nigral neurones possibly released from primary sensory afferents.     

The action of substance P on mesencephalic reticular and substantia nigral neurones of the rat.

Extracellular recordings were made from neurones in the mesencephalic reticular formation and substantianigra of the rat which was anaesthetized with urethane 1.5-2 g/kg i.p. Out of 44 cells tested 42 were excited by Substance P applied iontophoretically and in some cases this excitation was rapid. Evidence is presented for Substance P as a putative excitatory transmitter onto reticular and nigral neurones possibly released from primary sensory afferents.     

Effect of cyproheptadine on the octopamine-induced responses in the mammalian central nervous system

Summary Extracellular recordings have been made from rat thalamic neurones anaesthetized with urethane, 1.5–2 g/kg i.p. Iontophoretically applied octopamine excited certain thalamic neurones in the ventral basal complex while inhibiting others. Both effects were reversibly antagonized by iontophoretically applied cyproheptadine without affecting responses to noradrenaline and dopamine.Acknowledgment. We are grateful to Merck, Sharp and Dohme for a gift of cyproheptadine HCl.     

Role of serotonin in the diffuse inhibitory controls induced by nociceptive stimulation

In the anaesthetized Rat, the entire population of dorsal horn convergent neurones is differentially affected by a noxious stimulus: while exciting the segmental pool, it strongly inhibits the remaining population. The inhibitory effects, which involve supraspinal mechanisms, are reduced to a great extent in parachlorophenylalanine pretreated animals. The role of raphé-spinal serotonergic pathways in nociception is discussed.     

Is glutamic acid the pyramidal tract neurotransmitter?

Applied by microiontophoresis, 1-hydroxy-3-amino-pyrrolidone-2 (HA-966) antagonized excitation by glutamic acid but not by acetylcholine of neurones in the rat cuneate nucleus. HA-966 blocked the short latency excitation of cuneate neurones following stimulation of the pyramidal tract on 28 of 40 cells (70%). Thus, glutamate or a related amino-acid may be the neurotransmitter released by pyramidal tract neurones.     

Amine and amino acid microanalysis of two identified snail neurons with known characteristics

Résumé La microanalyse de l'amine et de l'amine acide de deux neurones identifiés a prouvé la présence de sérotonine dans l'un des neurones et son absence dans l'autre, celui qui contenait plus de méthionine. A l'exception d'un intéressant composé non identifié, les autres substances étaient essentiellement semblables dans les deux neurones.     

Slice cultures of cerebellar,hippocampal and hypothalamic tissue

Summary Cerebellar, hippocampal and hypothalamic slices prepared from newborn and 7-day-old rats were cultured by means of the roller-tube technique. Identification of cells was made easier by the fact that at least part of the characteristic cytoarchitecture of the tissue was preserved in vitro. Cerebellar Purkinje cells and neurones of the deep cerebellar nuclei were recognized on the basis of their size, their location within the culture and their dendritic arborization. Pyramidal cells of all hippocampal subfields displayed their characteristic basal and apical dendritic trees with numerous spinous processes. Hippocampal granule cells gave rise to a monopolar dendritic arbor; their axons terminated in the dentate hilus and CA3 region. Golgi-like immuniperoxidase staining allowed localization of groups of neurophysin-positive neurones in slices prepared from the anterior hypothalamus. These neurones, bilaterally bordering the third ventricle, usually displayed a simple dendritic arborization and fine beaded axons.—Cultivation of brain slices prepared from young rats offers particular advantages in that the cultured cells are organized in an organotypic monolayer and individual living neurones may be directly visualized.Acknowledgments. I would like to thank Dr J. Zimmer and Dr M. Sofroniew for their valuable help with the Timms and immunoperoxidase staining techniques and Mr R. Schlichter and L. Wohlfart for illustrating the culture procedure. The excellent technical assistance of Ms L. Rietschin and E. Hoffmann is gratefully acknowledged.     

Is glutamic acid the pyramidal tract neurotransmitter?

Summary Applied by microiontophoresis, 1-hydroxy-3-amino-pyrrolidone-2 (HA-966) antagonized excitation by glutamic acid but not by acetylcholine of neurones in the rat cuneate nucleus. HA-966 blocked the short latency excitation of cuneate neurones following stimulation of the pyramidal tract on 28 of 40 cells (70%). Thus, glutamate or a related amino-acid may be the neurotransmitter released by pyramidal tract neurones.Acknowledgment. I wish to thank Dr.J. C. Watkins for the gift of a sample of HA-966.     

Myosin isoenzymes during in vivo and in vitro differentiation of chick muscles

Muscle fibers differentiated, in vitro, from myoblasts of embryonic Pectoralis (presumptive fast) and embryonic Adductor magnus (presumptive slow) muscles synthesise the same type of myosin, which is identical to the type synthesised in day 10 embryonic muscles. This type of myosin comigrates with the third isozyme of the adult fast-twitch muscle. There is no change in the kind of myosin in cultures aged from 2 to 7 weeks, whereas during the in vivo differentiation of the same muscles, new isozymes appear which are different in the two muscles. With regard to myosin, the muscle fibers differentiated, in vitro, from myoblasts of fast or slow muscles expressed the same phenotype.     

Nervenzellen im Bereich des ösophagus der Grillen und ihre mögliche Funktion

Summary Multiterminal nerve cells have been found in the foregut of crickets (Acheta domesticus (L.),Gryllus campestris L.) which are sensitive to stretching the wall of the gut. These cells are spontaneously active and they respond to stretch in a phasic-tonic way. Within the ventricular nerves there are also neurones being spontaneously active.     

La barrière capillaire enzymatique pour la DOPA au niveau de quelques noyaux du tronc cérébral du rat

Summary An enzymatic barrier for Dopa exists at the level of the cerebral capillaries which changes Dopa into Dopamine by means of endothelial decarboxylase. It is abolished by a decarboxylase inhibitor. Its intensity is weaker in structures containing Dopamine (Striatum, Locus Niger). Neurones of the Raphé containing serotonin can be charged with catecholamines. There are close contacts between neurones and capillaries.     

Regeneration of entire legs in cockroaches as a model for developmental events

Summary Young cockroach nymphs have the ability to generate entire legs which become the same size as normal legs when the animal is an adult. Studies of the physiological, structural and biochemical properties of some of the regenerated muscles suggest that these muscles are different from normal ones.     

Histochemical localization of cholinesterases in the neural tissue of the pineal in the rhesus monkey.

The neural tissue of the monkey pineal contains both acetyl and butyryl cholinesterases. Acetylcholinesterase was localized in the cisternae of the nuclear membrane, rough endoplasmic reticulum, on the plasma membrane of the neurones, and on the axolemma of both non-myelinated and myelinated fibres. The enzyme was not found in the axosomatic or axo-dendritic synapses. It is therefore suggested that the pineal neurones have a cholinergic function rather than a cholinoceptive one.     

Some interesting points on the histochemistry of the cytoplasmic inclusions of the ageing spinal neurones of reptiles,birds and mammals

Résumé L'analyse histochimique comparée des neurones des Reptiles, des Oiseaux et des Mammifères révèle que les divers corps qui y sont inclus ont une histochimie identique. Les sphéroïdes lipides abondent dans les phospholipides des jeunes neurones qui sont transformés en corps triglycérides chez les adultes. Les corps lipides ne sont pas un produit de sécrétion de l'appareil canaliculaire de Golgi dont l'homologue a été observé seulement dans les neurones adultes. La substance de Nissl est pleine de RNA.     

Electrotonic synapses in the visceral ganglion of Planorbis

Summary In the visceral ganglion of Planorbis the postsynaptic neurones of the characterized dopamine neurone are connected by non-rectifying electrotonic junctions. The coupling, which is reduced by stimulation of the dopamine neurone and by applied dopamine, may be important in the generation of burst activity. Specialized areas of close apposition of membranes in the neuropile are considered to be the morphological correlate of electrotonic coupling.This work was supported by grants from the S. R. C. and M. R. C. to Dr G. A. Cottrell, whose help is gratefully acknowledged.