Differential expression of voltage-gated k' channels in glomus cells and sheath cells of cat carotid body

We have previously shown three types of cat carotid body cells according to the expression of voltage-gated K channels: One type possesses oxygen-sensitive K channels (A type), and the other possesses oxygen-insensitive K channels (B type). Some celis do not have voltage gated K Channels (C type). In ihis study we have investigated if these biophysical cell types correlate with hislologîca! cell types of the carotid body (glomus cells and sheath cells). Carotid bodies were harvested from anesthetized adult cats, and dissociated cells were cultured on a glass coverslip, which served as a bottom of a recording chamber. Cells with long processes were selected, and a whole cell configuration was obtained wilh a pipel contained Lucifer yellow to label the tested cells K" currents were measured by applying a voltage step from -60 mV of holding potential to +40 mV during normoxia (PO2 150 mmHg) and hypoxia (25 mmHg) After determination of biophysical cell types, the patch pipet was removed, and the cells were fixed with methanol Immunofluorescent techniques were applied to visualize tyrosine hydroxylase (TH) in glomus cells, and glial fibrillary acidic protein (GFAP) in sheath cells. The results were shown in the table, and they indicate that glomus cells express oxygen sensitive K⁺ channels, and sheath cells express oxygen-insensitive K⁺ ' channels.