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Sensory interaction with central 'generators' during respiration in the dogfish
1Department of Zoology, University of Amsterdam, The Netherlands.
Journal of Comparative Physiology. A, Sensory, Neural, and Behavioral Physiology
|April 1, 1988
Summary
This study reveals how sensory and motor nerves in dogfish gills coordinate breathing. Vagal nerve stimulation influences gill muscle activity and respiratory rhythm stability.
Area of Science:
- Neuroscience
- Comparative Physiology
- Marine Biology
Background:
- The regulation of gill ventilation in fish is complex, involving intricate neural circuits.
- The vagus nerve plays a crucial role in coordinating respiratory movements in elasmobranchs.
Purpose of the Study:
- To investigate the role of vagal sensory and motor nerve activity in the control of gill ventilation in dogfish (Scyliorhinus canicula).
- To elucidate the mechanisms by which vagal nerve stimulation affects respiratory rhythm and muscle activity.
Main Methods:
- Recording of neural activity from vagal nerve branches in decerebrate dogfish.
- Electrical stimulation of vagal sensory fibers to observe effects on ventilatory movements.
- Assessment of respiratory rhythm under conditions of paralysis (curare) and entrainment.
Main Results:
- Vagal motoneuronal activity precedes pharyngeal contraction, while sensory activity precedes gill expansion.
- Electrical stimulation of vagal sensory fibers evoked reflex muscle contractions, reset the respiratory cycle, and could entrain the respiratory rhythm.
- Vagal motor rhythm was disrupted by trigeminal nerve stimulation, but not when entrained by vagal stimulation.
Conclusions:
- Vagal sensory activity is critical for maintaining the stability of the neural circuits generating gill ventilation.
- The findings highlight the intricate interplay between sensory feedback and motor output in respiratory control.