Table 3.

Uncoupled respiration rates (%) of PC12 cells after different time of incubation with increasing concentration of Hg²⁺, Cd²⁺, or Cu²⁺.

Time (h)	[Hg2+], μM		[Cd2+], μM				[Cu2+], μM
	10	50	10	50	100	500	10	50	100
3	66 ± 11*	15 ± 3*	77 ± 2*	48 ± 3*	35 ± 3*	4 ± 4*	85 ± 20	81 ± 14	83 ± 14	77 ± 16
5					21 ± 3*
24	86 ± 7	2 ± 2*	91 ± 13	14 ± 5*	5 ± 2*	0	94 ± 8	82 ± 7	72 ± 6*	58 ± 17*
48	105 ± 5									48 ± 5*

Rate of oxygen uptake is presented in percentage of the maximal (fully uncoupled) respiration of the control cells. Mean ± SE; n = 3 independent experiments; *P < 0.05 compared to untreated control.