Propylene glycol releases calcium from mitochondrial stores in rat cerebrocortical synaptosomes

In Ca2+-free medium, propylene glycol (PG) increases the cytosolic-free Ca2+ concentration ([Ca2+]i) in rat cerebrocortical synaptosomes. In the current studies, the authors investigated the intracellular source of this Ca2+. PG (0.5-5% v/v) dose-dependently increased [Ca2+]i in Ca2+-free medium. The increase in [Ca2+]i was completely inhibited by pretreatment with the mitochondrial uncoupler, carbonylcyanide m-chlorophenylhydrazone (CCCP, 10 microM). The inhibitory effect of CCCP was dependent on the concentration and the pretreatment time. These results suggest that, in Ca2+-free medium, PG increases [Ca2+]i in rat cerebrocortical synaptosomes by releasing Ca2+ from mitochondrial stores.