Respiratory influences upon depressor and pressor responses to stimulation of the aortic nerve in the decerebrate cat

Riassunto Le risposte circolatorie alla stimolazione elettrica del nervo aortico sono notevolmente modificate dalla ventilazione polmonare. In particolare le risposte a stimoli di intensità intermedia ed elevata, che attivano oltre a fibre pressocettive anche fibre chemocettive, divengono da ipotensive ipertensive durante ipoventilazione. Gli effetti dell'ipoventilazione sono sempre riprodotti sia dall'ipercapnia (respirazione con CO₂ 5–7% in O₂) sia dall'ipossia (respirazione di O₂ 5–8% in N₂).

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This research has been sponsored jointly by the Aeronautical Systems Division, ASD and the Office of Aerospace Research, OAR, through its European Office, Office of Aerospace Research, United States Air Force, under Contract No. AF 61 (052)-253, and by Consiglio Nazionale delle Ricerche.     

Relationship between the resting blood pressure and depressor responses evoked by compression of the eyeballs

Résumé Les corrélations entre le niveau de repos de la pression artérielle et le degré des effets dépressifs provoqués par la compression des yeux sont positives. Leur valeur dépend de l'intensité de la stimulation. Elle atteint son maximum à une intensité semblable à celle qui conditionne la plus forte amplification des réactions étudiées.     

Interaction between human evoked electrospinograms elicited by segmental and descending volleys

Summary Interaction between the slow negative-positive waves of human evoked electrospinograms produced by descending and segmental volleys was tested under general anaesthesia. A partial occlusion was demonstrated in these slow waves.This work was supported in part by the Japanese Ministry of Education.     

Interaction between human evoked electrospinograms elicited by segmental and descending volleys.

Interaction between the slow negative-positive waves of human evoked electrospinograms produced by descending and segmental volleys was tested under general anaesthesia. A partial occlusion was demonstrated in these slow waves.     

Distribution of bilateral dorsal root potentials evoked by volleys in afferents entering lumbar and sacral segments of the spinal cord

Ipsilateral dorsal root potentials evoked by volleys entering lumbar and sacral segments of the cord are largest at the level of entry of afferent volleys. Contralateral potentials resulting from stimulation of any of these nerves attain maximum amplitude in lower sacral and upper caudal segments.     

Antidromic responses evoked in the central end of the phrenic nerve by stimulation of the ipsilateral dorsal column in the cat]

In 15 adult cats under nembutal anaesthesia the dorsal columns have been stimulated at the level of the first and the second cervical segments. Under these conditions antidromically evoked responses appear both on the ipsilateral radial and phrenic nerves. Some of the afferent phrenic fibres thus activated may be related to the diaphragm muscle receptors. In some experiments a group of thin fibres (conduction velocity comprised between 16-20 m/sec) were also activated.     

Distribution of bilateral dorsal root potentials evoked by volleys in afferents entering lumbar and sacral segments of the spinal cord

Summary Ipsilateral dorsal root potentials evoked by volleys entering lumbar and sacral segments of the cord are largest at the level of entry of afferent volleys. Contralateral potentials resulting from stimulation of any of these nerves attain maximum amplitude in lower sacral and upper caudal segments.     

Reflex motility of the stomach evoked by electrical stimulation of the hepatic vagus nerve

Summary Electrical stimulation of the cranial end of the cut hepatic branch of the vagus nerve produced an increase in the motility of the empty stomach in the rat, whereas systemic injection of insulin produced a gradual increase in the motility.Acknowledgment. The authors are indebted to Dr K. Yamaguchi and Prof. A. Niijima for their encouragement of the project.     

Inhibition and enhancement of photically evoked responses by different doses ofl-DOPA

Summary Administration of small doses ofl-DOPA (10 and 20 mg/kg) resulted in reduction in amplitude of photically evoked responses in the primary visual, association, and cerebellar vermal cortices, while large doses (40 and 80 mg/kg) produced enhancement.Acknowledgment. We thank Prof.K. Kuriyama and Sr.M. McCormick for their help.     

Prostaglandin E2 increases mechanically evoked potentials in the peripheral nerve

Summary Subdermal injections of PGE₂ (5 g) in the rat foot lead to increases in the potentials evoked in sensory nerve branches by the mechanical stimulation of the skin. This sensitization of both A and C fibres complements the previously described hyperalgesic effects of prostaglandins of the E series.     

Somatic evoked responses in cats during natural sleep

Riassunto Le risposte corticali evocate da stimoli somatici, sia periferici che centrali, aumentano di ampiezza durante il sonno profondo. Tale amplificazione è dovuta, almeno in parte, ad una facilitata trasmissione degli impulsi ascendenti a livello del nucleo ventro-postero-laterale del talamo.

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Part of these results has been presented at a meeting of the Società Italiana di Biologia Sperimentale held in Genova on July 25th 1962.     

Influence of the visual cortex upon collicular evoked responses in the rabbit

Summary In rabbit, the depression of the visual cortex by KCl showed an enhancement of the collicular evoked potentials. This enhancement revealed that the visual cortex had exerted a tonic type influence upon the superior colliculus. M. Dubuc was supported by training grant No. 217-617-489 of the Ministère de l'Education du Québec.     

Facilitation of the dorsat root potentials by volleys spreading caudally and cranially in the spinal cord

Summary Conditioning volleys spreading along 3 segments of the cord produce larger facilitation of bilateral dorsal root potentials in sacral cord than volleys in neighbouring dorsal roots used to evoke the testing depolarization. Contralateral potentials are more facilitated by volleys descending from lumbar than ascending from caudal segments.     

Influence of the visual cortex upon collicular evoked responses in the rabbit.

In rabbit, the depression of the visual cortex by KCl showed an enhancement of the collicular evoked potentials. This enhancement revealed that the visual cortex had exerted a tonic type influence upon the superior colliculus.     

Facilitation of the dorsal root potentials by volleys spreading caudally and cranially in the spinal cord.

Conditioning volleys spreading along 3 segments of the cord produce larger facilitation of bilateral dorsal root potentials in sacral cord than volleys in neighbouring dorsal roots used to evoke the testing depolarization. Contralateral potentials are more facilitated by volleys descending from lumbar than ascending from caudal segments.     

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.