Figure 2

Influence of honokiol on cellular responses to activation of M3 muscarinic receptors measured in the absence of extracellular calcium. CHO cells expressing the human M3 receptor were loaded with fura-2 to monitor changes in cytosolic calcium concentration. The cells were untreated or treated with the indicated concentrations of honokiol for 10 min immediately before measuring calcium content. Cells were switched to a calcium-free BSS 3 min before imaging. Each line represents the average response from 17-24 cells; each panel presents the results from a separate experiment. Essentially similar results were obtained in three other experiments. Carbamylcholine (10 μmol/l) was added at the time indicated by the first arrow. Calcium was added to the extracellular medium (final concentration = 2 mmol/l) at the time indicated by the second arrow.