Fig. 4. (Top ) Representative trace depicting the effect of tyrphostin 23 (Tyr; 100 μm) alone and in combination with propofol (100 μm) on capacitative Ca2+entry. After depletion of sarcoplasmic reticulum Ca2+stores with thapsigargin, capacitative Ca2+entry was compared in the absence or presence of tyrphostin 23 and tyrphostin 23 plus propofol, which were each added to the superfusion buffer 5 min before restoring extracellular Ca2+concentration ([Ca2+]o). (Bottom ) Summarized data showing that, although tyrphostin 23 alone attenuated (*P < 0.05) capacitative Ca2+entry, the addition of propofol resulted in a further reduction (†P < 0.05) in capacitative Ca2+entry (n = 7 cells).