Table 2.

In vivo inhibition of KD₅₀ of 2,3-dimethylmaleic anhydride on acetlycholinesterase in neural ganglion of P. americana and S. oryzae homogenate at different exposure.

Exposure period (min)	% of AChE inhibition (mean ± SE)
	P. americana		S. oryzae
	Control	Treated	Control	Treated
30	2.1 ± 0.4a	40.5 ± 2.4a	2.4 ± 0.2a	47. 2 ± 2.4a
60	4.2 ± 0.2b	80.3 ± 2.2b	6.3 ± 0.4b	63.2 ± 1.8b
90	5.8 ± 0.5c	90.2 ± 3.4c	7.2 ± 0.4c	87.4 ± 1.2c
120	8.3 ± 0.4d	98 ± 2.2d	8.8 ± 0.6d	90. 1 ± 3.2cd
150	10.2 ± 1.2e	98.2 ± 2.4de	13.6 ± 2.4e	96.8 ± 1.2e

The values were expressed within a column indicate that mean ± standard error of four replicates and significantly different (P < 0.05) by Newman-Keuls test.