Fig. 4.

Inhibitors of phospholipase and lipoxygenase reduce the responses to dopamine, APGWa, and FMRFa. A, Percentage reduction of the potassium current elicited by dopamine, APGWa, and FMRFa (top, middle, andbottom, respectively) after perfusion of the cells with standard medium (control), 0.01% DMSO-containing medium (DMSO), the inhib itor of AA-release 4-BPB (10 μm), the lipoxygenase inhibitor NDGA (15 μm), and the cyclooxygenase inhibitor indomethacin (Indom; 5 μm). Asterisks indicate significant difference with respect to the DMSO control (unpaired ttest; p < 0.01). Apart from controls in whichn = 6, experimental groups weren = 3 for each agonist. B, NDGA also blocks the current induced by bee venom-derived PLA₂, indicating that exogenous PLA₂acts specifically to produce AA. Shown are the average response amplitudes to applications of PLA₂ (50 U/ml) in the absence and presence of 15 μm NDGA (n = 11). NDGA was applied for 10 min before PLA₂ was tested.Inset, Superimposed traces showing a control response to PLA₂ and the strong reduction of this response by NDGA (responses from the same cell). *p < 0.01; paired t test.