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1
Content available remote

Chemoreceptor and vagal influences on genioglossal muscle responses to inspiratory resistive load

100%
Aleksandrova N. P.
Journal of Physiology and Pharmacology. Supplement
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2004
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tom 55
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nr 3
7-14
The present study was undertaken to determine the mechanisms underlying the involvement of upper airway dilating muscles in compensatory responses to added inspiratory resistive load. Experiments were performed in tracheostomized, anaesthetised rabbits. The effect of inspiratory resistive loading on the electromyographic activity of the genioglossus muscle, the major dilating muscle of the pharynx, was studied in vagotomized and vagally intact rabbits during spontaneous breathing with a hypoxic gas mixture (10% O2 in N2) or oxygen. In the vagally intact animals the peak value and duration of genioglossus muscle inspiratory activity increased in the first loaded breath before any noticeable change in the arterial blood gases. Hyperoxia decreased, whereas hypoxia increased the immediate response of the genioglossus activity to inspiratory loading. Removal of vagal volume-related feedback (by vagotomy) significantly increased the genioglossus muscle activity; the increase being more under hypoxia than under hyperoxia. In contrast to vagally intact animals, there was no first-breath increase in genioglossus activity during loading. The results indicate that the immediate involvement of the genioglossus muscle in response to inspiratory resistive load is mediated by vagal-volume feedback. Baseline oxygen tension before loading modulates the immediate reflex vagal-related response of the genioglossus muscle.
2

Antennal sensilla in Mallophaga in scanning electron microscope

100%
Zlotorzycka J., Kassner J.
Folia Histochemica et Cytobiologica
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1986
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tom 24
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nr 4
3
Content available remote

Influence of the stimulation of carotid body chemoreceptors on the gastric mucosal blood flow in artificially ventilated and spontaneously breathing rats

84%
Sinski M., Kowalczyk P., Stolarczyk A., Sawionek L., Przybylski J.
Journal of Physiology and Pharmacology
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2002
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tom 53
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nr 3
The cardiovascular effects of the stimulation of arterial chemoreceptors are different in spontaneously breathing and artificially ventilated animals. Respiratory failure and long term sojourn at high altitude coincide frequently with the occurrence of gastric ulceration. In both these situations a profound stimulation of arterial chemoreceptors is present. The purpose of the paper was to investigate the reflex effect of stimulation carotid chemoreceptors on gastric mucosal blood flow in the rat. Arterial chemoreceptors were stimulated by two methods (I) substitution gas mixture of 10% oxygen in nitrogen for room air and (II) direct injection of acid saline ( 0.05 ml, pH=6.8) into the distal part of left common carotid artery. In artificially ventilated rats stimulation of arterial chemoreceptors caused significant increase in gastric mucosal vascular resistance, accompanied by marked decline in blood flow. This effect was mediated by adrenergic mechanism. On the contrary to artificially ventilated rats, decline of gastric mucosal vascular resistance with concomitant increase in blood flow was found in spontaneously breathing animals. This effect was not abolished either by phentolamine or atropine. As vasodilatatory effect of arterial chemoreceptors stimulation was abolished by bilateral vagotomy, we postulate that non adrenergic and non cholinergic vagal fibers mediate observed vascular changes in gastric mucosa in spontaneously breathing rats. We hypothesize that in artificially ventilated patients with respiratory failure stimulation of arterial chemoreceptors by hypoxemia and or acidosis may contribute to the development of gastric mucosal lesions.
4
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Transient O2-dependent effects of CO2 on ventilation in the anesthetized mouse

84%
Pokorski M., Izumizaki M., Homma I.
Journal of Physiology and Pharmacology
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2005
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tom 56
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nr 3
In this study we sought to determine the effects of background hyperoxia on the ventilatory response to hypercapnia. We addressed this issue by examining the temporal profile of the first minute transients of minute ventilation, and its frequency and tidal components, in response to 5% and 10% CO2 each co-applied with the natural (balanced with air) and hyperoxic (balanced with O2) levels of oxygen. The study was performed on the urethane-anesthetized, tracheostomized, spontaneously breathing mouse, placed in a flow-through body plethysmograph. We identified an early suppressant effect of CO2-in-O2 on breathing frequency. The frequency declined to 88.5 ±1.4% and 87.8 ±1.9% relative to the pre-test, baseline level for 5% and 10% CO2, respectively. There was a compensatory rise in tidal volume and no major change in the overall ventilation. In contrast, CO2-in-Air resulted in ventilatory stimulation caused in equal measure by frequency and tidal components. Thus, the inhibitory effect on breathing frequency of the CO2-in-O2 resulted from the O2 content in the mixture and had the temporal characteristics consistent with carotid body function. In conclusion, transient O2-dependent effects can bear on the nascent hypercapnic ventilatory response. The complexity of the O2-CO2 interaction regarding the breathing pattern components should be taken into account while designing the optimal conditions for a hypercapnic test.
5
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Aging and expression of heme oxygenase-1 and endothelin-1 in the rat carotid body after chronic hypoxia

67%
Di Giulio C., Verratti V., Artese L., Petruccelli G., Walski M., Pokorski M.
Journal of Physiology and Pharmacology. Supplement
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2009
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tom 60
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nr 5
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