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Query: UMLS:C0010200 (cough)
 23,843 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The lowest concentrations of citric acid were measured that caused coughing in 10 normal subjects who inhaled successively higher concentrations. Two subjects did not cough at any concentration. In the remaining eight the threshold concentration was significantly higher when measured in the afternoon than it was in the morning (p less than 0.05). The expected diurnal variation in peak expiratory flow rate (PEFR) was found (significant in the whole group--p less than 0.05); but PEFR did not change significantly when measured before and immediately after coughing caused by citric acid inhalations. In a second group of 10 normal subjects two series of citric acid inhalations were given, separated by one hour. The total number of coughs was significantly lower on the second run (p less than 0.05). Thus diurnal variation and adaptation of the cough response must be taken into account when antitussive drugs are tested.
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PMID:Diurnal variation and adaptation of the cough response to citric acid in normal subjects. 406 Jan 6

Inhalation of aerosols of citric acid, histamine phosphate, or carbon dust, or air cooled to - 20 degrees C or rapid respiratory maneuvers (inspiration or expiration) results in an increase in airway resistance in some patients with asthma or bronchitis. It has been shown previously in animals that stimulation of cough receptors results in bronchoconstriction through efferent cholinergic pathways. In the patients studied, the administration of atropine sulfate, which would block such pathways, abolished the bronchoconstrictor effects of all the stimuli except large doses of histamine, which may exert a direct effect on airway smooth muscle. These data suggest that sensitized cough receptors may be involved in triggering reflex airway constriction in such patients.
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PMID:Role of autonomic nervous system and the cough reflex in the increased responsiveness of airways in patients with obstructive airway disease. 607 Mar 26

The main pharmacological activities of 2-(7'theophyllinemethyl)-1,3-dioxolane (ABC 12/3), a new theophyllinic derivative, were studied. This compound was shown to possess an extremely high anti-bronchospastic activity in vitro and in vivo, its effectiveness being much greater than that of theophylline; and it also showed a strong activity as an antitussive on experimental cough induced by citric acid or histamine aerosol. However the compound showed little activity on the intestinal smooth muscle, the cardiovascular and the central nervous systems. The acute toxicity of ABC 12/3 is rather low and therefore it should be possible to utilize it for therapeutic purposes in tracheobronchial diseases.
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PMID:Pharmacological researches on 2-(7'-theophyllinemethyl)1,3-dioxolane. 626 5

The cough threshold to citric acid inhalation was measured in eight subjects by single inhalations of increasing concentrations of citric acid until a cough was consistently produced. The cough threshold was measured before and after 60 mg glaucine, 60 mg codeine and matched placebo on three separate days a week apart. Base-line cough threshold in each subject was consistent from week to week. Codeine increased the threshold by more than one citric acid concentration in three subjects. Placebo and glaucine did not produce a threshold change of more than one citric acid concentration. We conclude that the citric acid threshold is a simple measure of antitussive activity. No such activity was found with glaucine.
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PMID:Assessment of antitussive effects by citric acid threshold. 634 1

The integrated surface abdominal electromyogram (EMG) has been used as a simple measurement of cough intensity which correlates well with the volume, air flow and noise produced in different coughs. Using the integrated abdominal EMG as a measure of cough intensity, dose response curves to inhaled citric acid can be drawn which are highly reproducible. We have studied the effects of codeine (60 mg) on these curves, and have demonstrated a reduction in cough intensity. It is suggested that this method of testing the effects of an antitussive on such a dose-response curve may be a useful one.
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PMID:An electromyographic method of objectively assessing cough intensity and use of the method to assess effects of codeine on the dose-response curve to citric acid. 648 76

The pathological changes in the airway epithelium of patients with asthma and viral upper respiratory tract infection is similar. We have shown that such infections temporarily increase the airway reactivity to histamine and lower the threshold for citric acid-induced cough in normal subjects. We have postulated that sensitisation of airway irritant receptors played a part in this phenomena. Other workers have confirmed these results and in dogs with airway infections an exaggerated discharge of irritant receptors has been shown in response to histamine challenge.
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PMID:Effect of airway infections on bronchial reactivity. 657 84

1. The relationship between coughing and spinal monosynaptic reflexes (SMR) in extensors and flexors was investigated in eight healthy subjects by using the Hoffmann technique. Coughing exerted major depression (81% in extensor and 83% in flexor SMR). This depressant effect began simultaneously with the first cough and lasted through the coughing phase. Complete recovery to initial values occurred an average of 40 s thereafter. 2. In comparison, mental tasks induced only a slight decrease in SMR amplitude. In contrast, the Mueller and Valsalva manoeuvres induced facilitation. 3. During coughing, large variations in extensor amplitudes were observed that were coupled with the ventilatory cycle. Slight facilitation was observed during inspiration, but expiration induced pronounced depression, occurring 0.20 s after the beginning of the expiratory period. Experiments performed during baseline breathing failed to show any change throughout inspiratory or expiratory phases. 4. Chemical stimulation of irritant receptors (inhalation of citric acid) produced no specific modification of extensor responses compared with the effect of placebo inhalation (distilled water). 5. These data suggest that coughing exerts a major depressant effect on motor activity via a loop that possibly includes cardiopulmonary receptors and inhibitory supraspinal descending pathways.
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PMID:Depressive effect of coughing on spinal monosynaptic reflexes in conscious man. 685 19

To determine whether anaesthesia of the intrathoracic airways would attenuate the development of exercise-induced asthma, we studied eight symptomless asthmatic patients by cycle ergometry after saline or lignocaine pretreatment while they were breathing air at 24 degrees C with 9.1 mg of H2O/l. Pulmonary mechanics were measured before and after the administration of each agent, and again five minutes after cessation of exercise. Sufficient lignocaine was administered to abolish the gag reflex and the cough response to aerosols of citric acid. Before exercise there were no significant differences for any lung function variable between the saline and lignocaine results. Equally, there were no significant differences between these agents for minute ventilation (VE) during exercise (VE lignocaine = 71.0 +/- 7.4 (SEM) l/min; VE saline 67.2 +/- 8.1 l/min;), or in the severity of the subsequent bronchospastic response (for example, the FEV1 with saline was 22.6 +/- 2.9% decrease, and with lignocaine 23.6 +/- 8.5%). Thus these results do not support the idea that there are thermally sensitive neural receptors in intrathoracic airways that play a role in the pathogenesis of exercise-induced asthma.
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PMID:Controlled-analysis of the effects of inhaled lignocaine in exercise-induced asthma. 715 12

1. In 10 patients with pulmonary fibrosis and in seven control subjects, we measured the pressure at the mouth 0 . 1 s after onset of an inspiration against occluded airway (P 0 . 1), minute ventilation (VI), breathing frequency (fr), tidal volume (VT), inspiratory duration (Ti) and calculated the mean inspiratory flow (VT/Ti) and the fraction of the breath cycle devoted to inspiration (Ti/T tot.). In the patients measurements were made at normal arterial oxygen saturations (SaO2), before and after lignocaine airway anaesthesia. 2. Efficacy of airway anaesthesia was tested by the cough response to citric acid inhalation. 3. In pulmonary fibrosis P 0 . 1, f1 and VT/Ti were greater than in the control subjects, VT and Ti were smaller and Ti/T tot. and VI were not different. 4. Effective airway anaesthesia did not modify P 0 . 1 and breathing pattern parameters observed in pulmonary fibrosis. 5. These results suggest that airway receptors do not contribute to a major extent to the control of breathing in pulmonary fibrosis.
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PMID:Role of vagal airway reflexes in control of ventilation in pulmonary fibrosis. 729 40

An aerosol of 4% lidocaine was delivered during the last third of inspiration to patients with bronchial asthma while they were quietly breathing. After this procedure, both cough reflex (inhalation of 10% citric acid) and gag reflex (mechanical irritation of the larynx) were absent in all patients for 15 to 20 min. This type of anesthesia was tolerated well by all patients, and did not significantly influence baseline pulmonary function tests. On another day, this procedure was used prior to treadmill exercise testing. Anesthesia blocked the development of exercise-induced bronchoconstriction (EIB) after the exercise period, as measured by FEV1, FEF25-75%, Vmax70% TLC, and specific airway conductance (SGaw). It was also found that the degree of minute ventilation (VE), as measured during exercise with airway anesthesia, significantly decreased (p < 0.01) compared with VE measured during exercise without lidocaine. The results suggested that local anesthesia of the upper and large airways in patients with bronchial asthma can significantly inhibit EIB and significantly decrease VE during moderate exercise. It can be postulated that mucosal receptors in the upper and large airways are directly involved in the initiation of EIB, and that their stimulation may be responsible for increased ventilation during exercise.
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PMID:Effect of lidocaine on the ventilatory and airway responses to exercise in asthmatics. 745 56


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