Amiloride 100 M OPC 0.5 mM DIDS 1.5 mM 30 min Amiloride 100 M Amiloride 100 M ATP 100 M OPC 0.5 mM DIDS 1.5 mM 30 min Amiloride 100 M 0 -20 2 ) m c /A-40 ( y t is -60 n e d t en -80 r r u C-100 -120 20 0 2 ) m /c -20 A ( y t is -40 n e d t ren -60 r u C -80 -100 120 ) % ( e d litu 80 p m a e v i t la 40 e R 0 B B Lee JH et al.: Ion Channel Modulators in Nasal Polyps 77 A C 0 2 ) /cm-20 A (y -40 t i s n de -60 t n rre -80 u C -100 -120 50 ) ? ( 2 ) 0 m c / A (y -50 t i s n e td-100 n e r r C-150 u -200 3 min A 4 min Fig. 1. Effects of DIDS, DPC, and ATP in the presence of amiloride on the Isc. (A) A raw trace representative of 17 experiments was shown. The majority of the remained Isc in the presence of amiloride is accounted for by DPC-sensitive chloride conductance. (B) Effects of DIDS and DPC on the Isc after activation of chloride secretion by ATP in the presence of amiloride. A raw trace representative of 7 experiments was shown. DPC: N-phenylanthranilic acid; DIDS: 4,4’-Diisothiocyanatostilbene-2,2’-disulfonic acid disodium salt hydrate. 0.1 1 ATP ( M) 10 100 300 0.1 1 UTP ( M) 10 100 300 0.1 1 10 100 Agonist ( M) Fig. 2. Dose-response relationships of ATP (A) and UTP (B) in the pres- ence of amiloride. (C) EC50 of ATP (dashed line) and UTP (continu- ous line) was 5.3 and 7.3 M, respectively (n=5). to =50.0±5.5 μA/cm2, n=7, Fig. 3B). In the presence of 100 μM 8-SPT, a P1 receptor blocker, the response of adenosine was decreased by 90.0±3.7% (from -50.0±5.5 to -23.4±6.5 μA/ cm2, n=7, Fig. 3B). P2X receptor agonists and other modulators for ion transport were introduced to test the effects on polyps (Fig. 4). The addi- tion of αβmeATP and BzATP (100 μM) had no significant res- ponse in the presence of amiloride (from -13.2±4.5 to -13.9± 3.9 μA/cm2 and -12.7±2.5 to -12.4±2.5 μA/cm2, respectively, n=5 each, Fig. 4A). The addition of genistein (20 μM), the CFTR