Activation of Na+ channels in GH3 cells and human pituitary adenoma cells by PACAP.
The effects of pituitary adenylate cyclase activating polypeptide (PACAP) on ion channels were examined in GH3 cells human pituitary adenoma cells. In GH3 cells, PACAP-38 (10-9 M) reversibly activated tetrodotoxin-sensitive NA+ channels but had little effect on nicardipine-sensitive Ca2+ channels. PACAP-induced increase in Na+ currents was inhibited by PACAP (6-38), a specific PACAP receptor antagonist, and Rp-cAMPs, an inhibitor for protein kinase A, and mimicked by 8-bromo-cAMP. In human pituitary adenoma cells, PACAP also activated tetrodotoxin-sensitive Na+ channels and growth hormone secretion. These results suggest the possibility that PACAP can activate voltage-gated Na+ channels via adenylate cyclase-protein kinase A pathway in the pituitary.
Koshimura
K
K
Department of Medicine, Shimane Medical University, Izumo, Japan. kunio@shimane-med.ac.jp
Murakami
Y
Y
Mitsushima
M
M
Hori
T
T
Kato
Y
Y
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000236:Adenoma; D002460:Cell Line; D019382:Human Growth Hormone / Q000378:metabolism; D006801:Humans; D008875:Middle Aged; D009479:Neuropeptides / Q000494:pharmacology*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism*; D015222:Sodium Channels / Q000187:drug effects / Q000378:metabolism*; D013779:Tetrodotoxin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
C495401:ADCYAP1 protein, human; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D015222:Sodium Channels; D019382:Human Growth Hormone; D015124:8-Bromo Cyclic Adenosine Monophosphate; D013779:Tetrodotoxin