Figure 4.

Effects of tramadol on [Ca²⁺]_i rises induced by nicotine in bovine adrenal chromaffin cells. These figures show average changes of the cytosolic Ca²⁺ concentration induced by nicotine (10 μM) with or without various concentrations of tramadol (1,10 and 100 μM) A and B. Nicotine was added for 20 s after pretreatment with tramadol (10 μM). Tramadol alone did not induce any change in basal [Ca²⁺]_i rises. Open bars mean the period for nicotine applications and closed bars indicate the period for tramadol applications. ***P<0.001 (n=16).