Figure 6. In vitro carotid sinus nerve CO₂ chemosensitivity is not increased by decreasing [glucose].

Single-fibre chemoafferent discharge recorded from one carotid body during control (10 mm glucose; above) and low-glucose superfusion (2 mm glucose; below). Discharge was binned into 20-s periods and frequency calculated as impulses s⁻¹ (Hz). Hypercapnia, raising the superfusate P_CO2 from 40 mmHg to 80 mmHg, indicated by the horizontal bars, increased the chemoreceptor discharge frequency during control glucose perfusate. This effect was absent during low glucose superfusion. On the right are shown four superimposed afferent action potentials from this recording. The vertical scale bar is 100 μV, horizontal scale bar 0.4 ms.