Accentuation by pertussis toxin of the 5-hydroxytryptamine-induced potentiation of ATP-evoked responses in rat pheochromocytoma cells.
We previously demonstrated that 5-hydroxytryptamine (5-HT) enhances the cationic current activated by extracellular ATP in rat pheochromocytoma PC12 cells. We report here that pertussis toxin (PTX) modulates this 5-HT-dependent enhancement in these cells. 5-HT potentiated ATP-evoked intracellular Ca2+ concentration ([Ca]i) rise and dopamine release over a concentration range from 1 to 100 microM. When cells were pre-treated with PTX, this potentiation was accentuated. Pretreatment with PTX also accentuated the 5-HT-dependent enhancement of the ATP-activated current. These results suggest that the enhancement by 5-HT of the ATP-evoked responses is negatively regulated by a mechanism mediated through PTX-sensitive GTP-binding protein.
Koizumi
S
S
Division of Pharmacology, National Institute of Health Sciences, Tokyo, Japan.
Ikeda
M
M
Nakazawa
K
K
Inoue
K
K
Nagamatsu
K
K
Hasegawa
A
A
Inoue
K
K
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D005071:Evoked Potentials / Q000187:drug effects*; D016716:PC12 Cells; D018408:Patch-Clamp Techniques; D037342:Pertussis Toxin; D051381:Rats; D012701:Serotonin / Q000494:pharmacology*; D010566:Virulence Factors, Bordetella
D010566:Virulence Factors, Bordetella; D012701:Serotonin; D000255:Adenosine Triphosphate; D037342:Pertussis Toxin; D002118:Calcium; D004298:Dopamine