Respiratory responses to chemical stimulation of the parabrachial nuclear complex in the rabbit

The respiratory role of the parabrachial nuclear complex (PNC) was investigated in α-chloralose–urethane anesthetized, vagotomized, paralysed and artificially ventilated rabbits by means of unilateral microinjections (10–20 nl) of 20 mM -homocysteic acid. Chemical stimulation elicited three main types of site-specific respiratory effects: excitatory, apneustic and inhibitory responses. The results suggest that the PNC plays a complex role in the control of breathing.