Fig. 5.

Schematic of the experimental arrangement to measure eNO, eCO₂ and breathing frequency in spontaneously breathing, conscious rats. Rats were placed into a two-compartment restraining tube for data collection periods of 10 min (thoracic compartment: volume displacement plethysmograph; head-out compartment: bias-flow of synthetic air with manifold to the NO-chemiluminescence and infrared CO₂-gas analyzers connected to a mass-flow controlled vacuum). ‘Flow’: mass flow meter/controllers. Dotted lines electrical connections, double lines: ducts for analyses in expired gas