Spontaneous transmitter release from nerve endings and contractile properties in the soleus and diaphragm muscles of senile rats

Zusammenfassung Die Frequenz der spontanen Mediatorfreilegung von Nervenendigungen und die Kontraktionsgeschwindigkeit sinken im Soleus- und Zwerchfellmuskel während des Alterns von Ratten. Die Frequenzerniedrigung ist weit stärker ausgeprägt im Soleus als im Zwerchfellmuskel, während die Unterschiede in den Kontraktionsgeschwindigkeiten unbeträchtlich sind. Die relativ geringe Senkung der ACh-Freisetzung im senilen Zwerchfellmuskel wird zur intensiven Nerv-Impulsaktivität beim Atmungsprozess in Beziehung gebracht.     

Cobalt-staining of motor nerve endings in the locust (Locusta migratoria)

Summary A method is described for axonal cobalt-staining of peripheral nerve branches. First experiments were carried out on abdominal muscles of the locust.     

Control of muscle insulin receptors by the motor nerve

Summary I¹²⁵ insulin binding and the uptake of oxygen and 2-deoxyglucose are increased in skeletal muscle after denervation, suggesting an increase in insulin receptors (IR). Sustained increases in the number of affinity of IR molecules may account for some properties of denervated muscle fibres.Supported by the Medical Research Service of the Veterans Administration.     

Spontaneous junctional currents in Drosophila muscle fibres: effects of temperature, membrane potential and ethanol.

Fast, slow and fast multiquantal spontaneous junctional currents were recorded from glutamate sensitive muscle fibres of Drosophila larvae. Decrease of temperature and hyperpolarization prolonged the time course of fast currents. Ethanol (0.4 M) markedly shortened their duration, whereas several other drugs known to modify the time course of currents at cholinergic synapses were ineffective at this neuromuscular junction.     

Coordinated activation of muscle fibres by different conduction velocities in branches of a crustacean motor axon

Summary Higher conduction velocities in branches of the fast excitor axon to distal muscle fibres ensure that these fibres are activated almost simultaneously with proximal fibres in the claw closer muscle of lobsters, producing a contraction of maximal force.Supported by Muscular Dystrophy Association and National Research Council of Canada.Supported by National Institute of Health and Muscular Dystrophy Association of America.     

Monoamine oxidase inhibition by d-amphetamine in ganglia and nerve endings

Summary The inhibition of monoamine oxidase (MAO) activity by d-amphetamine was measured in homogenates of cat superior cervical ganglion and nictitating membrane, using tyramine (TM) and noradrenaline (NA) as substrates. In both tissues, d-amphetamine was shown to be a competitive inhibitor of the oxidation of TM. The Ki for d-amphetamine, as a MAO inhibitor, was lower in the ganglia than in the peripheral nerve endings.Supported by a Contract from the National Research Council of Argentina (CONICET) (Res. 67/79).     

Histochemical changes in upper motor lesions,parkinsonism and diuse. Differential effect on white and red muscle fibres

Zusammenfassung Muskelbiopsiematerial aus Patienten mit motorischen Störungen bei Verletzung der Pyramidenbahn, Parkinsonismus und Kreuzbandverletzung wurde mit histochemischer Technik analysiert. Eine Atrophie der weissen Fasern wurde bei Pyramidenbahnverletzung und Parkinsonismus beobachtet. Kreuzbandverletzung ergab hauptsächlich Atrophie der roten Fasern, während diese bei dauernder Spastizität und Rigidität Hypertrophietendenzen zeigen.     

A simple silver nitrate impregnation of nerve fibres with preservation of acetylcholinesterase activity at the motor end-plate

Summary A rapid silver nitrate impregnation of nerve fibres has been devised to maintain a histochemically detectable acetylcholinesterase activity at the motor end-plates.We thank Mrs Paulette Cloup and Mr D. Levieux for their valuable technical assistance.     

A simple silver nitrate impregnation of nerve fibres with preservation of acetylcholinesterase activity at the motor end-plate

A rapid silver nitrate impregnation of nerve fibres has been devised to maintain a histochemically detectable acetylcholinesterase activity at the motor end-plates.     

Fluctuations in excitability of single myelinated nerve fibres

Résumé Il est possible de montrer des fluctuations aléatoires de l'excitabilité électrique de fibres nerveuses myélinisées isolées excitées au moyen de chocs proches du seuil. L'amplitude de cette fluctuation a été comparée pour des excitants rectangulaires de deux durées (0,1 et 10 msec); elle est plus grande quand on utilise des chocs brefs. Ces résultats suggèrent que les composantes de relativement haute fréquence du spectre de la fluctuation sont importantes.     

Evolution in time of transmitter release at frog neuromuscular junction]

It has previously been shown that the unitary quantal end-plate potentials observed at synapses blocked by low Ca++ high Mg++ ringer, belong to distinct clusters according to their amplitude, time to peak and latency characteristics. These clusters correspond probably to distinct releasing units dispersed along the presynaptic terminal branches. The distribution versus time of the occurence of unitary potentials belonging to one latency cluster has been studied over long lasting evoked nerve activity (stimulation frequencies: 1 to 10 Hz). It was observed that transmitter release at one releasing site is statistically periodic with emitting periods separated by rest periods. At a given end-plate the period of emitting activity seems to be independent from one emitting site to another.