Abstract
Vagal control of respiration is mediated by the classical Hering-Breuer reflexes. The Hering-Breuer reflexes are easy detected in infants and disturbance in the functioning of vagal pathways may play a role in breathing disorders during the early postnatal period. Central terminations of vagal afferents are found in the nucleus of solitary tract (NTS). IL-1β receptors are located in the same site of NTS. This suggests involvement of IL-1β in the modulation of vagal control of ventilation during the early postnatal period in infections and inflammations.
Our goal was to study the effects of elevated system level of IL-1β on breathing pattern and the Hering-Breuer reflexes in anaesthetized rats in which these reflexes are also easy detected.
The experiments were performed on tracheostomized rats, which were anaesthetized intraperitoneally with urethane (1000 mg kg-1). Recombinant human IL-1β was administered in the jugular vein in an amount of 500 ng dissolved in 1 ml of saline. In the control experiments the same amount of saline solution containing no IL-1β was injected into the vein. Tracheal occlusion was used in order to test the Hering-Breuer reflex. All animal procedures were conducted in accordance with the ethical guidelines of the European Community Council Directives 86/609/EEC.
It was obtained that the rise in IL-1β level in blood evokes the increase in minute ventilation, respiratory rate, tidal volume and inspiratory swings of intrathoracic pressure. Moreover it was sown that IL-1β enhances Hering-Breuer inspiratory-inhibitory reflex which mediates volume-related feedback in breathing system.
We concluded that IL-1β may disturb vagal control of respiration in infections and inflammations in infants.
- © 2014 ERS
