Table 6.
Acetylcholinesterase inhibition by various organophosphates in rat serum.
| Serum Acetylcholinesterase | Serum + Selective Inhibitors | |||
|---|---|---|---|---|
| PND 1 | PND 12 | PND 70 | PND 70 | |
| Oxon | IC50 nM (95%CI) | IC50 nM (95%CI) | IC50 nM (95%CI) | IC50 nM (95%CI) |
| Azinphos-methyl-oxon | 117 (58,175) | 127 (68,185) | 178 (118,236) | 232 (160,304) |
| Methyl paraoxon | 137 (70,163) | 114 (68,161) | 219* (172,265) | 75 (18,131) |
| Dicapthon-oxon | 94 (86,101) | 84 (77,92) | 144* (137,152) | 46* (37,55) |
| Methyl coumaphos-oxon | 217 (195,238) | 212 (191,234) | 295* (273,317) | 138* (110,163) |
| Paraoxon | 56 (46,64) | 47 (38,56) | 106* (97,116) | 48 (36,60) |
| Chlorpyrifos-oxon | 10 (7,13) | 10 (6,13) | 54* (51,57) | 7 (3,11) |
| Ethyl cyanophos-oxon | 1140 (926,1354) | 1359 (1144,1573) | 1534 (1319,1748) | 1234 (972,1496) |
| Ethyl ronnel-oxon | 462 (409,515) | 477 (424,530) | 490 (437,543) | 399 (334,463) |
| Diazoxon | 157 (127,186) | 194 (164,223) | 309* (280,338) | 213 (177,248) |
| Naftalophos | 39 (29,49) | 34 (24,44) | 67* (57,77) | 32 (20,44) |
| Nitropyrifos-oxon | 46 (43,49) | 51 (47,54) | 83* (80,86) | 23* (19,27) |
| Phoxim-oxon | 30 (25,35) | 31 (26,36) | 109* (103,114) | 29 (23,35) |
f
IC50s are expressed as means with 95% confidence intervals of three independent replications for each age group. Means for each compound followed by an * are significantly different (p < 0.05) among ages within a tissue. Serum + selective inhibitors for CaE (SCPP) and BChE (ethopropazine).