ISSN:
1432-2013
Keywords:
Arterial chemoreceptors
;
Cat
;
Control of breathing
;
Electrical stimulation
;
Intracranial chemosensitivity
;
Oesophageal pressure
;
Respiration
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Ventilatory responses to stimulation of chemoreceptor afferents were studied in the anesthetized, spontaneously breathing cat. Short bursts of electrical stimuli were applied, at various times in the inspiratory or expiratory phase of consecutive breaths, to the carotid sinus (CSN) and aortic nerves (AN) and to the ventral medulla (VM), and effects on tidal volume (V T), inspiratory, expiratory and cycle durationst I,t E,t tot) and in ventilation (E) were measured. The responses evoked by stimulating CSN, AN and VM were qualitatively the same, although there were quantitative differences. It was found that effects of stimulation in expiration were restricted to the expiratory phase, and vice versa for inspiration. Stimulation during both inspiration and expiration resulted in increasedV T, by increasing end-inspiratory or decreasing end-expiratory lung volume, respectively, and also increased ventilation, E. These effects were most marked in response to stimulation in inspiration. During both phases there was an increasing effect with increasing delay of the stimulus,t St, from onset of inspiration or expiration, respectively. There was a continuous increase int I, from below control to above control values, with increasingt St during inspiration and similarly fort E during expiration. Hence, the total respiratory cycle duration was shortened when a stimulus was applied early in either phase, and was prolonged, when it was applied late. The results show that stimulation of peripheral and of central chemoafferents exerts qualitatively similar effects on respiration. The central neuronal mechanisms generating both inspiration and expiration show the same changes in reactivity in the respiratory cycle.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00589255
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