Role of vagus nerves and inhalative aerosols of acetylcholine and histamine on dynamic pulmonary elastance in anesthetized spontaneously breathing and artificially ventilated dog

The role of the vagus nerves on resting respiratory resistance (R1) and dynamic lung elastance (Edyn) and the mechanism of action of inhaled aerosol of histamine (Hist) and acetylcholine (ACH) were studied in anesthetized spontaneously breathing and artificially ventilated dogs. Observations were al...

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Bibliographic Details
Published in:Research in experimental medicine 1982-01, Vol.181 (3), p.155-170
Main Authors: Islam, M S, Ulmer, W T
Format: Article
Language:English
Subjects:
Acetylcholine - pharmacology
Aerosols
Animals
Dogs
Elasticity
Electric Stimulation
Female
Histamine - pharmacology
Lung - physiology
Male
Respiration - drug effects
Respiration, Artificial
Tidal Volume
Vagotomy
Vagus Nerve - physiology
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Summary:The role of the vagus nerves on resting respiratory resistance (R1) and dynamic lung elastance (Edyn) and the mechanism of action of inhaled aerosol of histamine (Hist) and acetylcholine (ACH) were studied in anesthetized spontaneously breathing and artificially ventilated dogs. Observations were also extended to study the effect of electrical stimuli to cut ends of both vagi alone and during inhalation of aerosols. Bilateral cervical vagal blockade by local application of novocaine solution (2.5%) or bilateral vagotomy reduced resting R1 and Edyn and prevented increase of these parameters following inhalation of aerosols of Hist or ACH in spontaneously breathing dogs. However, the similar vagal blockade or vagotomy in artificially ventilated animals showed neither an influence on resting R1 and Edyn nor could it prevent their increase following the exposure to aerosol of Hist or ACH. Electrical stimuli to the peripheral cut ends of vagi induced slight increase in R1 and Edyn, but the effect on heart rate and systemic blood pressure was very strong. The combined effects of aerosol of Hist or ACH and electrical stimuli were additive. It is concluded that inhalation of aerosol of Hist or ACH produced two kinds of effects on respiration: (1) Increased respiratory rates with reduced tidal volume and with bronchoconstriction which were vagus-dependent (spontaneous breathing model), and (2) bronchoconstriction which was a direct response of smooth muscle without involving a reflex (artificial ventilation model).
ISSN:0300-9130
1433-8580
DOI:10.1007/bf01851186