Propylene glycol increases cytosolic free calcium in rat cerebrocortical synaptosomes.
In these studies, the authors investigated the effect of propylene glycol (PG) on the cytosolic free Ca2+ concentration ([Ca2+]i) in rat cerebrocortical synaptosomes using the fluorescent Ca2+ indicator fura-2. PG (0.5-5% v/v) increased [Ca2+]i in a concentration-dependent manner. The PG-induced increase in [Ca2+]i was inhibited approximately 50% by the omission of extracellular Ca2+ or the addition of Ni2+ (100 microM). Decrease of extracellular Na+ (6.2 mM) or addition of tetrodotoxin (1 microM), verapamil (10 microM), nifedipine (10 microM), omega-agatoxin IVA (200 nM), omega-conotoxin GVIA (1 microM), or omega-conotoxin MVIIC (1 microM) had no effect on the increase in [Ca2+]i. Also, addition of TMB-8 (100 microM), ryanodine (50 microM) or thapsigargin (1 microM) did not modify the increase in [Ca2+]i in the absence of extracellular Ca2+. These results suggest that PG increases [Ca2+]i in rat cerebrocortical synaptosomes by both stimulating Ca2+ entry through a Ni2+-sensitive pathway and releasing Ca2+ from TMB-8-, ryanodine- and thapsigargin-insensitive Ca2+ stores.
Satoh
Eiki
E
Department of Pathobiological Science, and Research Center for Animal Hygiene and Food Safety, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan. es@obihiro.ac.jp
Murakami
Kei
K
Nishimura
Masakazu
M
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002540:Cerebral Cortex / Q000166:cytology*; D003600:Cytosol / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D016257:Fura-2 / Q000378:metabolism; D008297:Male; D019946:Propylene Glycol / Q000494:pharmacology*; D051381:Rats; D012433:Ryanodine / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism; D026941:Sodium Channel Blockers / Q000494:pharmacology; D012997:Solvents / Q000494:pharmacology; D013574:Synaptosomes / Q000187:drug effects* / Q000378:metabolism; D013779:Tetrodotoxin / Q000494:pharmacology; D019284:Thapsigargin / Q000494:pharmacology
D002121:Calcium Channel Blockers; D004791:Enzyme Inhibitors; D026941:Sodium Channel Blockers; D012997:Solvents; D012433:Ryanodine; D013779:Tetrodotoxin; D019284:Thapsigargin; D019946:Propylene Glycol; D012964:Sodium; D002118:Calcium; D016257:Fura-2