The purpose of a study by Balzamo et al. (A-24) was to investigate, in anesthetized rabbits, the effects of mechanical ventilation on the concentration of substance P (SP) measured by radioimmunoassay in nerves and muscles associated with ventilation and participating in the sensory innervation of the respiratory apparatus and heart. SP is a neurotransmitter located in primary sensory neurons in the central and autonomic nervous systems. Among the data collected were the following measures of SP concentration in cervical vagus nerves (X) and corresponding nodose ganglia

(NG), right and left sides:

SPXright SPNGright SPXleft SPNGleft 0.6500 9.6300 3.3000 1.9300 2.5600 3.7800 0.6200 2.8700 1.1300 7.3900 0.9600 1.3100 1.5500 3.2800 2.7000 5.6400 35.9000 22.0000 4.5000 9.1000 19.0000 22.8000 8.6000 8.0000 13.6000 2.3000 7.0000 8.3000 8.0000 15.8000 4.1000 4.7000 7.4000 1.6000 5.5000 2.5000 3.3000 11.6000 9.7000 8.0000 19.8000 18.0000 13.8000 8.0000 8.5000 6.2000 11.0000 17.2000 5.4000 7.8000 11.9000 5.3000 11.9000 16.9000 8.2000 10.6000 47.7000 35.9000 3.9000 3.3000 14.2000 10.2000 3.2000 1.9000 2.9000 1.6000 2.7000 3.5000 6.6000 3.7000 2.8000 2.5000 3.7000 1.3000