Respiration, chemical stimuli

Kaya et aL monitored the respiration activity of HeLa cells. Similar to other cell substrate, a decrease in the respiration activity following chemical stimulus (KCN, ethyl alcohol, and antimy-cin) was observed. Respiration activity of HeLa cells was also monitored on micropatterns of HeLa cells. The oxygen pattern mapped around the patterns with a Pt electrode demonstrated that fully adhered cells consumed more oxygen than round-shaped cells, which are often dying. 

The Chemical Stimuli. The chemical stimuli of respiration have been known for many years. Before the start of the twentieth century there was some agreement on the important chemical components responsible for ventilatory control. As early as 1868 it was reported that hypoxia (abnormally low oxygen supply) stimulated ventilatory response beyond normal levels (9). This was followed by observations that acid perfusion also stimulates respiration (10). In 1892 J. S. Haldane and L. Smith (II) carried out a series of tests on the ventilatory behavior of subjects breathing in a closed chamber where the carbon dioxide accumulated with time. The observations were similar to those observed previously—i.e.9 a small increase in C02 concentration resulted in significant increases in the ventilation. By using a C02 adsorber in the chamber, the breathing was unaffected until the 02 content in air dropped from 21 to 15.5%. These tests showed that except for cases of low 02 supply, CO2 is the principal stimulus of respiration. 

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