Effects of carotid sinus nerve stimulation on respiratory sinus arrhythmia and respiratory blood pressure waves of the dog

The effect on the amplitudes of RSA and RBPW of the time of the stimulus in the cardiac cycle, and also of continuous stimulation were studied. When the stimulus train was applied near peak systole the amplitudes of RSA and RBPW decreased. Stimulation in late systole increased both RSA and RBPW. Continuous stimulation did not exert any effects on RSA and RBPW.     

Effects of carotid sinus nerve stimulation on respiratory sinus arrhythmia and respiratory blood pressure waves of the dog

Summary The effect on the amplitudes of RSA and RBPW of the time of the stimulus in the cardiac cycle, and also of continuous stimulation were studied. When the stimulus train was applied near peak systole the amplitudes of RSA and RBPW decreased. Stimulation in late systole increased both RSA and RBPW. Continuous stimulation did not exert any effects on RSA and RBPW.     

Effect of norepinephrine and vasopressin on carotid sinus baroreceptor activity in the anesthetized rabbit

Summary Norepinephrine (NE) 10^–6 M or vasopressin (VP) 12.5 U/ml were injected into the isolated carotid sinus of anesthetized rabbits. The sinus was exposed either to the arterial pressure or to a pressure controlled reservoir. Multifiber and single fiber recordings were made. Both NE and VP increased baroreceptor activity at all sinus pressures but decreased activity in a few fibers. The results are consistent with the drugs having their effects on smooth muscle fibers in the adventitia.Acknowledgments. This work was supported by grants from the Medical Research Council of Canada and the B.C. Heart Foundation. The authors are grateful to J. Sharp and D. Morton for their excellent assistance.     

Influence of continuous and intermittent (R-wave triggered) electrical stimulation of the carotid sinus nerve on the static characteristic of the circulatory regulator

Zusammenfassung Bei narkotisierten Hunden wurde der Karotissinusnerv sowhl mit Dauerimpulsen als auch mit R-Zacken-gesteuerten Impulszügen elektrisch gereizt. Die Blutdruckcharakteristik zeigt, dass der Messbereich des Kreislaufreglers unter kontinuierlicher und ohne Reizung bei etwa gleichen Druckwerten liegt. Die Reizung mittels Impulszügen führt dagegen zu einer Verlagerung des Messbereiches zu niederen endosinualen Drücken.     

A negative inotropic response of cat atria to sympathetic nerve stimulation or norepinephrine

Zusammenfassung Isolierte, sympathisch innervierte Katzenvorhöfe wurden durch den rechten Nervus accelerans mit Impulsen von 1–5 msec Dauer und mit einer Frequenz von 0.5–60 Impulsen/sec stimuliert. In allen Präparaten wurde eine positiv chronotrope Wirkung beobachtet, während nur in 52% der Fälle eine inotrope Wirkung nachweisbar war. Bei 26% war die Kontraktionsstärke nicht beeinflusst, während bei 22% eine negativ inotrope Wirkung festgestellt wurde, für deren Variieren bis jetzt keine Erklärung gefunden werden konnte.

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Formerly pre-doctoral Fellow (U.S.P.H.S. Grant No. 5-T4-CA-5012).

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Pre-doctoral Fellow (U.S.P.H.S. Grant No. 5-T4-CA-5012).

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Established investigator of the American Heart Association.     

Frequency of spontaneous impulsation in rat cervical sympathetic nerve preganglionic fibres after chemical sympathectomy

Summary The frequency of spontaneous activity of single preganglionic fibres in the cervical sympathetic nerve of sympathectomized and intact animals was compared, and was found to be higher in the sympathectomized group, averaging 5.9±1.4 pulses per sec, compared with 2.3±0.5 in the control group.     

The effect of prolonged sympathetic stimulation on conduit vessel diameter

Zusammenfassung Wird die Reizfrequenz 8 imp/sec nicht überschritten, vermögen mittelgrosse Arterien — ungleich den Resistenzgefässen — während 10 min andauernder Sympathicusreizung ohne Erschlaffung in anhaltender Kontraktion zu verharren. Bei Anwendung höherer Reizfrequenzen ist eine Tendenz zur Erschlaffung der Gefässmuskeln trotz andauernder Stimulation bemerkbar.-Rezeptoren-Erregung scheint zur Erschlaffung quantitativ beizutragen.     

Carotid chemoreceptor influence on the cardiac sympathetic nerve discharge

Summary Pure stimulation of carotid chemoreceptors induces, as a primary effect, the general spontaneous activation of both the cardioexcitatory and the cardioinhibitory medullary centres. These effects have been shown by keeping constant those parameters which, when modified, produced secondary effects hiding the investigated primary ones.     

Carotid chemoreceptor influence on the cardiac sympathetic nerve discharge.

Pure stimulation of carotid chemoreceptors induces, as a primary effect, the general spontaneous activation of both the cardioexcitatory and the cardioinhibitory medullary centres. These effects have been shown by keeping constant those parameters which, when modified, produced secondary effects hiding the investigated primary ones.     

Functional reinnervation of cat sympathetic ganglia with splenic nerve homografts

Zusammenfassung Sympathische Ganglien, wenn mit Fasern desN. splenicus reinnerviert, bilden 2 pharmakologisch differente Synapsengruppen: normale, vom cholinergischen Typ und ca. 20% exitatorische vom «monoaminergischen» Typ, wenn sie von adrenergen Fasern reinnerviert wurden.     

Influence of thalamic stimulation on cortical epileptogenic focus

Summary Single stimuli applied to the non-specific thalamic nuclei do not change the activity of a cortical epileptogenic focus whereas rhythmic stimulation of these structures transforms the interictal activity into an ictal one.     

Post-tetanic changes of bilateral dorsal root potentials evoked by stimulation of the cutaneous afferents

Summary In spinal cats following tetanic stimulation of the cutaneous nerve bilateral dorsal root potentials in the lumbar spinal cord are depressed. Because of differences between ipsi- and contralateral potentials, this depression can usually be evoked only on one side of the cord.     

Excitation of sham rage behaviour by controlled electrical stimulation of group I muscle afferents

Riassunto La stimolazione elettrica ad alta cadenza (100–600 c/sec) del puro contingente di fibre muscolari appartenenti al gruppo I è in grado di scatenare accessi di falsa rabbia nel gatto decorticato, anche dopo ablazione del cervelletto e somministrazione di curarizzanti.

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This research has been sponsored by the Air Force Office of Scientific Research, through the European Office of Aerospace Research (OAR), United States Air Force, under Grant AF EOAR 65-6, and by the Consiglio Nazionale delle Ricerche (Electrophysiology Group).     

Tension of the lower abdominal aorta as influenced by sympathetic stimulation

Zusammenfassung Blutdruck und Durchmesser der Aorta abdominalis wurden in vivo bei Ruhe und während Sympathikusreizung zur Berechnung der Wandstärke und-Spannung direkt registriert.     

Activation of sustained sympathetic vasodilatation in dog by spinal cord stimulation

Summary Electrical stimulation in lateral sites of the upper cervical spinal cord evoked vasodilatation after adrenergic blockade. Sympathetic fibres mediating sustained vasodilatation were shown to be separate from adrenergic sympathetic fibres since the adrenergic vasoconstrictor response in the paw evoked by vasomotor stimulation in the medulla was not reversed to vasodilatation after bretylium.Supported by USPHS Grant No. HL 08570 and part of thesis work by Dr.Rolewicz.     

Significance of ‘empty vesicles’ in postganglionic sympathetic nerve terminals

Résumé Nous avons montré que dans les terminaisons nerveuses sympathiques de l'iris de chat, la proportion de vésicules à contenu osmiophile (noradrénaline) dépend essentiellement de la technique de fixation. Par ailleurs, après incubation des iris dans des solutions de noradrénaline et après fixation convenable, la quasi-totalité de ces vésicules renferment de la noradrénaline. Nous concluons que ces vésicules représentent une population potentiellement homogène, toutes étant capables de stoquer la noradrénaline.     

The effect of asphyxia and re-oxygenation on bilateral dorsal root potentials produced by stimulation of the cutaneous afferents

Résumé Les potentiels conditionnants et les tests effectués sur la racine dorsale des deux cotés de la moelle montrent une sensibilité différenciée à l'asphyxie. Après le rétablissement de l'oxygénation la dépression du potentiel ipsilatéral testé est augmentée et les potentiels contralatéraux n'apparaissent qu'après un retard prolongé.     

Influence of thalamic stimulation on cortical epileptogenic focus.

Single stimuli applied to the non-specific thalamic nuclei do not change the activity of a cortical epileptogenic focus whereas rhythmic stimulation of these structures transforms the interictal activity into an ictal one.