Effects of lignocaine blockades and kainic acid lesions in the Bötzinger complex on spontaneous expiratory activity and cough reflex responses in the rabbit.

We investigated the role played by Bötzinger complex (Böt. c.) region in the genesis of the cough reflex and expiratory drive to expiratory neurons of the caudal ventral respiratory group (cVRG) in pentobarbitone-anesthetized spontaneously breathing rabbits. Phrenic nerve and abdominal muscle activities were monitored. Microinjections (30-50 nl) of 4% lignocaine or 4.7 mM kainic acid in the Böt. c. region suppressed spontaneous rhythmic expiratory activity as well as the inspiratory and expiratory components of the cough reflex evoked by mechanical stimulation of the tracheobronchial tree. These results support the view that neurons located in the Böt. c. have an important role not only in the genesis of the synaptic drive to cVRG expiratory neurons, but also in determining the overall characteristics of the cough motor pattern.