Prolonged methacholine-induced bronchoconstriction in dogs. 1979

J W Ramsdell, and P F Georghiou

We studied the effect of prolonged airways obstruction induced by extended cholinergic stimulation in five anesthetized, mechanically ventilated dogs. A continuous intravenous metacholine infusion was utilized to maintain pulmonary resistance (RL) at 200--1500% preinfusion levels for 13--23 h. At maximum RL (18.86 +/- 7.74 vs. 2.09 +/- 0.18 (mean +/- SD) cmH2O/ (L/S) PREINfusion; P less than 0.01), dynamic lung compliance (Cdyn) fell from 67.5 +/- 14.6 to 32.7 +/- 11.6 ml/cmH2O (P less than 0.005) and arterial partial pressure of oxygen (PaO2) fell modestly from 95.8 +/- 6.1 Torr preinfusion to 83.2 +/- 12.7 Torr (P less than 0.05). Tachyphylaxis to methacholine developed, requiring increases in infusion rates to maintain elevated RL. Abnormalities in lung function resolved promptly upon termination of the infusion. Two similarly instrumented control animals ventilated for 19 and 25 h without metacholine infusion had no change in RL, Cdyn, or PaO2. Histological examination of the lungs revealed no differences between infused and control animals. In spite of marked increases in RL, prolonged cholinergic stimulation produced only mild changes in gas exchange and no sustained changes in lung function or structure.

UI MeSH Term Description Entries
D008168 Lung Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood. Lungs
D008170 Lung Compliance The capability of the LUNGS to distend under pressure as measured by pulmonary volume change per unit pressure change. While not a complete description of the pressure-volume properties of the lung, it is nevertheless useful in practice as a measure of the comparative stiffness of the lung. (From Best & Taylor's Physiological Basis of Medical Practice, 12th ed, p562) Compliance, Lung,Compliances, Lung,Lung Compliances
D008176 Lung Volume Measurements Measurement of the amount of air that the lungs may contain at various points in the respiratory cycle. Lung Capacities,Lung Volumes,Capacity, Lung,Lung Capacity,Lung Volume,Lung Volume Measurement,Measurement, Lung Volume,Volume, Lung
D008688 Methacholine Compounds A group of compounds that are derivatives of beta-methylacetylcholine (methacholine). Compounds, Methacholine
D012119 Respiration The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration ( Breathing
D001986 Bronchial Spasm Spasmodic contraction of the smooth muscle of the bronchi. Bronchospasm,Bronchial Spasms,Bronchospasms,Spasm, Bronchial,Spasms, Bronchial
D004285 Dogs The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065) Canis familiaris,Dog
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia

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