Apparent activation energy of the nerve impulse conduction

Résumé On définit la notion d'énergie apparente d'activation de la transmission nerveuse et on calcule les valeurs de l'enthalpie d'activation de ce processus. Les résultats sont discutés par rapport au mécanisme moléculaire de la conduction.

---

---

This paper is based on an investigation in progress which will be submitted byD.-G. Mrgineanu in partial fulfilment of the requirements for a Doctoral Degree in Biophysics under the leadership of Prof. Dr.V. Vasilescu.     

Sensory functions of the chorda tympani nerve in the chicken

Summary The peripheral course of the chorda tympani nerve in the chicken was described and the area of the mouth it innervates was investigated by mechanical stimulation of the oral epithelium. Afferent neural activity recorded from the chorda tympani nerve showed that it relays information from oral chemoreceptors, mechanoreceptors, thermoreceptors and possibly nociceptors. The results indicate that the previously held ideas on the function of the chorda tympani nerve in the chicken are incorrect.     

Spatial filtration in the nerve networks]

A simplified neuronal model leads to studies of multiunit nerve nets. Properties of spatial integration and differentiation are exhibited according to the structure of the interconnections. A spatial periodicity of nervous signal appears in nets with backward lateral inhibitions. It is a fundamental property of this structure.     

Endothelial nerve fibres in the cornea of the frogRana ridibunda

Summary The ultrastructural study of the frog cornea revealed the existence of intraendothelial nerve fibres. These nerve fibres are unmyelinated elements but surrounded by cytoplasmic lamellae of Schwann cells.Supported by D.C.I.N.P. Grant 78-77.     

Variation in the number and size of myelinated nerve fibers regenerated after repeated localized freezing of the sciatic nerve of rats]

The number and size of myelinated fibres have been determined in the nerve to medial head of the gastrocnemius muscle of Rats in which the sciatic nerve had been frozen locally 1 to 5 times at monthly intervals. The contralateral nerve was used as a control. When the measurements were made one month after the last freezing, the number of fibres increased progressively until the 3rd freezing, reaching about 220% of the normal value. No higher values were observed after 4 or 5 freezings. The mean diameter of fibres decreased with the number of operations. When the measurements were made 3, 6, 12 or 18 months after the 3rd freezing, the number of fibres decreased by about 30% between the 1st and the 3rd month and then stabilized. The mean diameter of fibres increased progressively. However, at the 18th month, the size of the myelinated fibres had not reached the normal value.     

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.     

Adrenergic nerve endings in the peripheral autonomic ganglion

Zusammenfassung Mittels elektronenmikroskopischer Untersuchungen wird die Anwesenheit adrenergischer Nervenendigungen im Ganglion hypogastricum des Meerschweinchens bewiesen.     

An experimental method for compressing the sciatic nerve

Zusammenfassung Ein leichter Druck wurde auf den Nervus ischiadicus der Ratte ausgeübt. Die electromyographischen Veränderungen sind den Veränderungen in pathologisch umklammerten menschlichen Nerven ähnlich. Die pathologische Anatomie dieser Nerven wird jetzt untersucht.     

An histochemical study of the nerve supply to the developing alimentary tract

Riassunto I neuroblasti dei plessi intramurali del canale alimentare mostrano attività acetilcolinesterasica istochimicamente dimostrabile sin dalle prime fasi di differenziazione. Essi sono riconoscibili nei differenti tratti del canale secondo una successione cronologica sovrapponibile a quella di comparsa di fibre estriseche con identici caratteri istochimici. Le tappe di penetrazione di queste fibre sono differenti nel polio, a confronto con quanto si osserva nel ratto e nel coniglio.     

Use of glyoxylic acid in the demonstration of autonomic nerve profiles

Summary 2% glyoxylic acid buffered to pH 7 could be used to improve the localization of cholinergic, adrenergic and nonspecific nerve profiles both in frozen sections and stretch preparations. The results are better than those obtained by conventional techniques, exhibiting the distinct reactions, with the least possible background and diffusion. The results are quickly obtained.