Figure 2. Effect of pre-treatment with a β₁-antagonist (atenolol), a β₂-antagonist (ICI 118,551), or vehicle on norepinephrine (10 nM) inhibition of capsaicin-evoked release of iCGRP from bovine dental pulp. The β-adrenoceptor antagonists (both at 100 nM) or vehicle was pre-treated for 7 min prior to application of norepinephrine (10 nM) or vehicle for an additional 7 min. All groups were then stimulated with capsaicin (10 µM) for 7 min. ** p < 0.01 vs. vehicle and ICI 118,551 groups. Error bars are SEM. N = 6-8/group.