Figure 12. The WHBP family.

WHBP descendants assist studies of integrated cardiorespiratory control. A and A1, thoracic preparation with data illustrating rhythmic splanchnic (sympathetic) bursts produced in response to specific thoracic spinal cord ischaemia. B, cervical and thoracic preparation and C, WHBP, provided as a reference. D and D1, dual perfused preparation with data showing PACAP‐38 activation of normoxic carotid bodies reverses central apnoea caused by specific brainstem hypocapnia (data from Fiamma et al., 2013). E and E1, triple perfused preparation with data showing greater splanchnic, phrenic and vagus nerve responses to specific brainstem ischaemia (carotid body and thoracic spinal cord maintained under baseline conditions). Note the hyperpnoea followed by apnoea and gasps concurrent with sympathetic activation. F, illustration of the ‘udder’ (exit of only one perfusion line is illustrated for clarity; red and blue are oxygenated and discharged perfusate, respectively) and PID pressure feedback system. The pressure feedback system is used initially to tune the preparation with a temperature‐dependent pressure ramp and then to maintain the perfusion to the CNS compartment(s) at 90 mmHg. Modifications to the classic WHBP are: (1) the vagi and cardiac depressor nerves are ligated in the neck region; (2) sucrose replaces Ficoll as an oncotic agent as it is less expensive; (3) brainstem temperature is increased from 31°C to 33°C, and (4) brainstem $P_{\mathrm{C}{\mathrm{O}}_2}$ is increased from 35 to 40 Torr and perfusate [K⁺] is reduced from 5 to 4 mM.