Fig. 6.
Comparison of INa inhibition in wild-type (WT) and σ1-receptor knockout (KO) myocytes. A: average inhibition by each ligand at 100 μM was determined from INa traces in Fig. 5. Bars represent means ± SE for n = 3–4. There is a significant difference between current inhibition by SKF-10047 and (+)-pentazocine in the two systems (*P < 0.05). B: immunoprecipitation-photolabeling experiment with [125I]-iodoazidococaine demonstrated σ1-receptor expression in wild-type mouse heart membranes and confirmed the elimination of σ1-receptors in knockout mouse heart membranes. Haloperidol (5 μM) reduced photolabeling in wild-type mice; however, in knockout mice, there was no photolabeling either with or without haloperidol.