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Spontane und reizbedingte Änderungen der antidromen Erregbarkeit von bulbären respiratorischen Nervenzellen der Katze

  • R. von Baumgarten
  • S. Nakayama
Article

Zusammenfassung

1. Die Erregbarkeit inspiratorischer und exspiratorischer Neurone der Medulla oblongata ist, gemessen an ihrer antidromen Invasionsbereitschaft, am größten während der spontanen Entladungsperioden, weniger groß unmittelbar vor und am kleinsten nach den Entladungsperioden.

2. Während der Hyperventilationsapnoe ist die Erregbarkeit an den von uns geprüften inspiratorischen Neuronen deutlich größer als während der Atempause zwischen zwei spontanen respiratorischen Entladungsperioden.

3. Durch Erhöhung der Reizstärke an den absteigenden Atmungsbahnen im Rückenmark gelingt es, zusätzliche antidrome Entladungen auch in den Atempausen auszulösen. Dies kann durch fördernde synaptische Querverbindungen zwischen den Atmungsneuronen erklärt werden.

4. Antidrome Reizung exspiratorischer Neurone führt zu kurzfristiger Hemmung der inspiratorischen Neurone. Dieser Befund wird mit der reziproken Innervation inspiratorischer und exspiratorischer Neurone über Axonkollateralen erklärt.

5. Bei antidromer Reizung mit frequenten Impulsen, sowie auch bei niederfrequenter Reizung in den Intervallen zwischen den spontanen Entladungsperioden tendieren respiratorische Zell-Aktionspotentiale besonders leicht zur „Disintegration“, Latenzzeitverlängerung und periodischer Gruppenbildung.

Abstract

1. The excitability of inspiratory and expiratory neurones in the medulla oblongata was measured by means of their facility to be invaded antidromically. Their antidromic excitability was found to be greatest during periods of spontaneous discharging, less immediately before, and least immediately after such discharge period.

2. The antidromic excitability of the tested inspiratory neurones was markedly increased during hyperventilation apnoea, compared with that during the pause between two spontaneous respiratory discharge periods.

3. It is possible to trigger additional antidromic discharges even in the respiratory pauses by augmenting the stimulation voltage applied to the descending respiratory pathway. This may be explained by facilitating synaptic interconnections between the respiratory neurones.

4. Antidromic stimulation of expiratory neurones brings about transient inhibition of inspiratory neurones. This finding may best be explained by reciprocal innervation of inspiratory and expiratory neurones by axon collaterals.

5. Action potentials from medullary respiratory nerve cells tended easily to disintegrate into their “A” and “B” fractions when antidromic tetanization was applied. They also showed prolongation of their latencies and a tendency for periodic following and failing to follow the antidromic stimuli.

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Copyright information

© Springer-Verlag 1964

Authors and Affiliations

  • R. von Baumgarten
    • 1
  • S. Nakayama
    • 1
    • 2
  1. 1.Aus dem Physiologischen Institut der Universität GöttingenGermany
  2. 2.Universität OkayamaJapan

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