Oculomotor reflex evoked by vibrassae stimulation in the cat]

The oculomotor effects of vibrissae stimulation have been studied in the "encéphale isolé" non-anaesthetized Cat. Intracellular recording of lateral rectus motoneurones showed an excitatory projection via the ipsilateral infraorbital nerve to these motoneurones. The afferent fibers are type A alpha, recuited with a low threshold (0.2-0.5 mA) and convey information about vibrissae displacement.     

Depressor effects of muscarinic and non-muscarinic mediation induced by lateral hypothalamic stimulation in the cat

Transient sympathetically-mediated depressor effects were induced by stimulation of a small locus in the lateral hypothalamic peri-fornical region, medial to the fields of Forel. The ganglionic blocking agent, atropine methyl nitrate (ATMN), was used to show that muscarinic as well as non-muscarinic sympathetic ganglion receptor neurotransmission was involved. Evidence is presented that stimulation of this LH site co-activates a number of mechanisms and that depending on which of these are activated, the ganglionic blocking agent ATMN may either block, reverse or potentiate the depressor effect.     

Generalized inhibition of spinal reflexes induced by cutaneous nerve stimulation in unrestrained cats

Riassunto Nell'animale integro non anestetizzato la stimolazione a bassa frequenza delle fibre cutanee del gruppo II produce una riduzione generalizzata del tono posturale e dei riflessi spinali mono- e polisinaptici, che si accompagna di solito, ma non necessariamente, ad un quadro di sincronizzazione elettroencefalografica. In particolari condizioni sperimentali la stimolazione cutanea suddetta può anche precipitare il quadro di sonno desincronizzato.

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This investigation was supported by PHS research grant B-2990 from the National Institute of Neurological Diseases and Blindness, N.I.H., Public Health Service (U.S.A.).     

Regional blood flow antagonism induced by central thermal stimulation in the conscious dog

Zusammenfassung Am wachen Hund wurde bei selektiver thermischer Reizung von Rückenmark und Hypothalamus ein regionaler Durchblutungsantagonismus für das kutane und intestinale Gefässgebiet als thermoregulatorische Antwort nachgewiesen.     

Inhibition of a monosynaptic reflex by electrical stimulation of the basal forebrain or the orbital gyrus in the cat

Zusammenfassung Der monosynaptische Reflex des Nervus massetericus, durch elektrische Reizung des Nucleus mesencephalicus des Trigeminus hervorgerufen und vom Nervus massetericus abgeleitet, konnte durch Reizung bestimmt umschriebener Gebiete des präoptischen basalen Telencephalons oder durch Reizung des Gyrus orbital im Katzen-Cortex effektiv gehemmt werden. Entsprechende Reizung der gleichen Hirngebiete führt zur Synchronisation des Elektrocorticogramms und ruft Schlaf hervor.     

The role of the substantia nigra on the rage reaction elicited by hypothalamic stimulation,in the cat

Summary The effects of substantia nigra stimulation on the rage reaction evoked by hypothalamic activation were studied. The reference value of the rage reaction was the latency of the hissing, which was constant in all animals when hypothalamic stimulation was performed with the same parameters. Simultaneous activation of substantia nigra and hypothalamus determined a significant decrease in hissing latency. The influence of the substantia nigra on the affective components of the aggressive behavior is underlined.This work was supported by a grant from the Consiglio Nazionale delle Ricerche Roma, Italy.     

The role of the substantia nigra on the rage reaction elicited by hypothalamic stimulation, in the cat

The effects of substantia nigra stimulation on the rage reaction evoked by hypothalamic activation were studied. The reference value of the rage reaction was the latency of the hissing, which was constant in all animals when hypothalamic stimulation was performed with the same parameters. Simultaneous activation of substantia nigra and hypothalamus determined a significant decrease in hissing latency. The influence of the substantia nigra on the affective components of the aggressive behavior is underlined.     

Facilitation of avoidance conditioning by reticular stimulation in the cat]

Learning is facilitated in Cats by posttrial reticular stimulation. It has been pointed out that this stimulation has no immediate anterograde effect and does not evoke any change in the cortical, motor or autonomic functions during its delivery. Moreover this stimulation has no effect on the time course of cortical and autonomic responses to the conditioned stimulus. Therefore, these results suggest that reticular stimulation has a specific action on memory consolidation or information processing.     

Depressor effects of muscarinic and non-muscarinic mediation induced by lateral hypothalamic stimulation in the rat

Summary Transient sympathetically-mediated depressor effects were induced by stimulation of a small locus in the lateral hypothalamic peri-fornical region, medial to the fields of Forel. The ganglionic blocking agent, atropine methyl nitrate (ATMN), was used to show that muscarinic as well as non-muscarinic sympathetic ganglion receptor neurotransmission was involved. Evidence is presented that stimulation of this LH site co-activates a number of mechanisms and that depending on which of these are activated, the ganglionic blocking agent ATMN may either block, reverse or potentiate the depressor effect.     

Sleep induced by the administration of melatonin (5-methoxy-N-acetyltryptamine) to the hypothalamus in unrestrained cats

Zusammenfassung An nicht narkotisierten Katzen wurde die Wirkung einer direkten lokalen chemischen Reizung subkortikaler Strukturen durch Melatonin untersucht. Diese Substanz, appliziert im Bereich der Area praeoptica, löste trophotropische Effekte und Schlaf aus.     

Changes in the distensibility of the cat aortic arch induced by noradrenaline

Summary In the isolated preparation of the aortic arch of the cat, noradrenaline (NA) reduced at low pre-loads, and increased at high pre-loads, the arterial wall distensibility. For each dose of NA, the changes were directly related to the pressure level in the system.     

The effect of lidocaine on the secretion induced by cholera toxin in the cat small intestine

The intraluminal administration of lidocaine, a local anaesthetic agent, inhibits the net loss of fluid into the intestinal lumen produced by cholera toxin in the cat. It is suggested that the activation of a nervous reflex is involved in the pathogenesis of cholera.     

The effect of lidocaine on the secretion induced by cholera toxin in the cat small intestine

Summary The intraluminal administration of lidocaine, a local anaesthetic agent, inhibits the net loss of fluid into the intestinal lumen produced by cholera toxin in the cat. It is suggested that the activation of a nervous reflex is involved in the pathogenesis of cholera.This research was sponsored by grants from the Swedish Medical Research Council (14X-2855), from the Swedish Society for Medical Sciences, from Magnus Bergvalls Stiftelse and from the Medical Faculty, University of Göteborg.     

Effect of stimulation on synaptic vesicles in the superior cervical ganglion of the cat

Résumé La stimulation préganglionique à 60/sec pendant 4 min produit un épuisement des vésicules synaptiques et une réduction de 30% du contenu de l'acétylcholine. Après cette période de stimulation, on observe fréquemment l'enflure de l'éclatement des mitochondries aux extrémités des nerfs. Ces changements dans l'ultrastructure de ces dernières ne se sont pas encore montrés reversibles lorsque l'on laisse par la suite les ganglions se reposer pendant plusieurs minutes.

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This research was supported by a grant from the Medical Research Council of Canada.     

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.     

Antidromic inhibition of presumed fusimotor neurones by repetitive stimulation of the ventral root in the decerebrate cat

Résumé On a enregistré des décharges de 17 fibres fusimotrices dont on suppose l'existence dans les filaments de racines ventrales des chats décérébrés. 8 fibres ont été inhibées par stimulation répétée de la portion centrale isolée du reste de la racine ventrale. Ces résultats montrent qu'il existe une inhibition antidromique dans les neurones fusimoteurs.