Corticotropin-releasing factor stimulates Ca2+ influx in cultured rat astrocytes.
Corticotropin-releasing factor (CRF) increased intracellular Ca2+ concentration in single astrocytes. The effect in increasing intracellular Ca2+ was not observed in Ca2(+)-free solution. Furthermore, CRF at concentrations more than 10 nM stimulated 45Ca2+ uptake in cultured rat astrocytes. The action was blocked by alpha-helical CRF(9-41) in a competitive manner, but not by nifedipine and 3,4-dichlorobenzamil. On the other hand, CRF did not stimulate cAMP formation, cGMP formation and phosphoinositide hydrolysis in astrocytes. These results indicate that CRF increases Ca2+ influx via an activation of CRF receptors in a cAMP-independent mechanism in cultured astrocytes.
Takuma
K
K
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Osaka University, Japan.
Matsuda
T
T
Yoshikawa
T
T
Kitanaka
J
J
Gotoh
M
M
Hayata
K
K
Baba
A
A
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000378:metabolism*; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D007700:Kinetics; D009543:Nifedipine / Q000494:pharmacology; D010716:Phosphatidylinositols / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D010716:Phosphatidylinositols; D000584:Amiloride; D003346:Corticotropin-Releasing Hormone; D000242:Cyclic AMP; D006152:Cyclic GMP; D009543:Nifedipine; D002118:Calcium; D015056:1-Methyl-3-isobutylxanthine