Figure 1. The NO donor SNP markedly inhibits the single L-channel activity in bovine chromaffin cells.
A, representative traces of L-channel activity, recorded in a cell-attached patch containing more than one channel under control conditions (left) and during exposure to 200 μM SNP (right). ω-CTx-MVIIC (10 μM), Bay K 8644 (5 μM) and a mixture of purinergic and opioidergic receptor antagonists (100 μM suramin, 10 μM naloxone) were present in the pipette solution. Bottom traces are averaged currents calculated over 10 (control) and 40 sweeps (SNP) from the same patch. B, NPoversus time before (▪) and during SNP exposure (□). Horizontal segments indicate the selected traces shown in A. C, averaged currents obtained from 13 patches, taking 10 traces in control and 40 traces from the third to the sixth minute of SNP application from each individual patch. D, NPoversus time for a representative control cell. Channel activity was tested for rundown for 18 min.