Table 1.

Exposure of ex vivo aortic rings to PCB 104 for 4 or 6 h increases the EC50 of acetylcholine. Thoracic aortic rings obtained from male Sprague–Dawley rats were exposed to 3, 10 or 20 μM PCB 104 for 4 or 6 h. Following PCB exposure acetylcholine-induced endothelium-dependent relaxation was determined and EC 50 measured. Data is expressed as mean ± SEM from 6 animals.

Exposure time	4 h	6 h
Control	1.1 × 10−7 ± 0.2 × 10−7 M	0.8 × 10−7 ± 0.2 × 10−7 M
PCB 104 3 μM	2.0 × 10−7 ± 0.6 × 10−7 M*	5.6 × 10−7 ± 3.3 × 10−7 M*
PCB 104 10 μM	4.1 × 10−7 ± 1.2 × 10−7 M*	8.3 × 10−7 ± 3.7 × 10−7 M*
PCB 104 20 μM	9.4 × 10−7 ± 1 × 10−7 M*	15.4 × 10−7 ± 7.7 × 10−7 M*

^*p < 0.05 vs. untreated rings.