| The purpose of this study was to determine if passive stretch of rat soleus muscles will induce increases in total muscle [ Ca2+ ] ( TCC ) and MCC . ^^^ TCC ( +62 % ) and MCC ( +56 % ) were elevated in the S muscles . ^^^ Increases in TCC in the S condition indicate that stretch results in Ca2+ influx from the extracellular space , which is supported by the observation that when S muscles were incubated in Ca ( 2+ ) free buffer , TCC and MCC did not increase . ^^^ High concentrations of verapamil ( 0 . 25 0 . 75 mM ) blocked the elevations in TCC and MCC in the S muscles , but the magnitude of the drug concentration required makes it questionable whether the effect resulted from specific blockade of slow voltage sensitive Ca2+ channels . ( ABSTRACT TRUNCATED AT 250 WORDS ) . ^^^ |