Reflex changes in breathing pattern evoked by inhalation of wood smoke in rats
- National Yang-Ming Medical College, Taipei (China)
The acute ventilatory response to inhalation of wood smoke was studied in 58 anesthetized Sprague-Dawley rats. Wood smoke ([approximately]6 ml) was inhaled spontaneously via a tracheal cannula. Within the first two breaths of smoke inhalation, either a slowing of respiration (SR) (n=39) or an augmented inspiration (AI) (n=19) was elicited consistently in each rat. The SR was primarily due to a prolongation of expiratory duration, whereas the AI was characterized by a two-step inspiratory flow leading to an exceedingly large tidal volume. Both initial responses, usually accompanied by bradycardia and hypotension, were reduced by inhaling smoke at a decreased concentration. After these initial responses, a delayed tachypnea developed and reached its peak 6-10 breaths after inhalation of smoke. Both the SR and AI were completely abolished by bilateral cervical vagotomy. In contrast, the delayed tachypneic response was not prevented by vagotomy but was significantly attenuated by denervation of peripheral chemoreceptors. The authors conclude that the initial responses to inhalation of several tidal breaths of wood smoke are mediated through vagal bronchopulmonary afferents, whereas the delayed tachypnea may involve nonvagal mechanisms that include a stimulation of peripheral chemoreceptors.
- OSTI ID:
- 7060474
- Journal Information:
- Journal of Applied Physiology (1985); (United States), Vol. 76:6; ISSN 8750-7587
- Country of Publication:
- United States
- Language:
- English
Similar Records
Autonomic cardiovascular responses to smoke exposure in conscious rats
In vitro receptor autoradiography reveals angiotensin IL (ANG II) binding associated with sensory and motor components of the vagus