Activation of medullary post-inspiratory related neurons during clonidine-induced central apnea in anesthetized goats.

Abstract

α2-adrenoceptors (α2-ARs) are widely distributed in the CNS including brainstem sites associated with cardiorespiratory control. 1,2 Several lines of evidence strongly suggest a role for α2-ARs in the regulation of respiratory rhythm. We have recently demonstrated that systemic administration of clonidine and other α2-AR agonists cause profound disturbances in respiratory pattern in the goat that are characterized by alternating episodes of tachypnea and respiratory depression (prolonged and variable expiratory time intervals).3-8 Dysrhythmic breathing induced by α2-AR agonists in the goat is associated with continuous tonic activation of expiratory-related drive in laryngeal4,5 and pharyngeal motoneurons6,8 leading to active airway closure during central apnea.6,8