Increasing Intracellular calcium of guinea pig ventricular myocytes induced by platelet activating factor through IP3 pathway.
We used Fluo-3/AM to examine the effect of platelet-activating factor on the intracellular Ca2+([Ca2+]i) levels in isolated myocytes of guinea pig ventricle. Myocytes were isolated with Langendorff perfusion technique and were challenged with platelet-activating factor. Addition of platelet-activating factor (1 pM to 10 nM) significantly increased the [Ca2+]i in the presence and absence of extracellular Ca2+. The notion that increases in intracellular Ca2+ induced by platelet-activating factor is the result of stimulation of intracellular Ca2+ pool rather than increasing Ca2+ influx was further supported by the whole cell patch-clamp experiments in which the platelet-activating factor did not alter the activity of L-type of Ca2+ channels (I(Ca-L)). Treatment of myocytes with ryanodine failed to abolish the stimulatory effect of platelet-activating factor on [Ca2+]i. In contrast, inhibition of IP3-sensitive Ca2+ release pool with 2-aminoethoxydiphenyl borate (2-APB) blocked the effect of platelet-activating factor. We conclude that the platelet-activating factor-induced increase in intracellular Ca2+ is mediated by stimulation of IP3 receptor but not by stimulation of I(Ca-L) and ryanodine-sensitive receptor.
Chu
Wen-Feng
WF
Department of Pharmacology, Harbin Medical University, and Bio-pharmaceutical Key Laboratory of Heilongjiang Province-Incubator of State Key Laboratory, Harbin, 150086, PR China.
Sun
Hong-Li
HL
Dong
De-Li
DL
Qiao
Guo-Fen
GF
Yang
Bao-Feng
BF
D000814:Aniline Compounds; D000818:Animals; D001896:Boron Compounds / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000187:drug effects* / Q000378:metabolism; D020013:Calcium Signaling; D004305:Dose-Response Relationship, Drug; D005456:Fluorescent Dyes; D006168:Guinea Pigs; D006352:Heart Ventricles / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D066298:In Vitro Techniques; D053496:Inositol 1,4,5-Trisphosphate Receptors; D008564:Membrane Potentials; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism; D010972:Platelet Activating Factor / Q000494:pharmacology*; D018160:Receptors, Cytoplasmic and Nuclear / Q000187:drug effects* / Q000378:metabolism; D013997:Time Factors; D014966:Xanthenes
D000814:Aniline Compounds; D001896:Boron Compounds; D015220:Calcium Channels; D005456:Fluorescent Dyes; D053496:Inositol 1,4,5-Trisphosphate Receptors; D010972:Platelet Activating Factor; D018160:Receptors, Cytoplasmic and Nuclear; D014966:Xanthenes; C059715:Fluo-3; C109986:2-aminoethoxydiphenyl borate; D002118:Calcium