Basic fibroblast growth factor regulates ionic currents and excitability of fetal rat carotid body chemoreceptors.
Basic fibroblast growth factor (bFGF) and nerve growth factor (NGF) are known mitogens and/or differentiation factors for cells of the sympathoadrenal lineage. Though carotid body (CB) chemoreceptors (type 1 cells) are considered part of this lineage, their response to bFGF is unknown and so far they appear unresponsive to NGF in vitro. In this study we use whole-cell recording to investigate whether bFGF (and NGF) can influence the development of ionic currents in these chemoreceptors, cultured from fetal (E18-19) rat pups. bFGF (10ng/ml) significantly augmented both transient inward Na+ and outward K+ currents in type 1 cells after only 2 days of treatment; after normalizing for the accompanying increase in cell size, as indicated by whole-cell capacitance, the Na+ current density was nonetheless increased by bFGF. Unlike controls, bFGF-treated type 1 cells readily fired action potentials following depolarization. These effects were not mimicked by NGF (100 ng/ml) treatment. Since the carotid body is one of the most richly vascularized organs and bFGF is a potent angiogenic factor, it is conceivable that variations in local bFGF concentrations during fetal development may contribute to the known species differences in CB chemoreceptor excitability.
Zhong
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Department of Biology, McMaster University, Hamilton, Ontario, Canada.
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D000818:Animals; D002344:Carotid Body / Q000502:physiology / Q000648:ultrastructure*; D048429:Cell Size / Q000187:drug effects; D002478:Cells, Cultured / Q000378:metabolism; D002628:Chemoreceptor Cells / Q000187:drug effects* / Q000502:physiology; D005260:Female; D005333:Fetus / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology*; D018408:Patch-Clamp Techniques; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar; D012964:Sodium / Q000378:metabolism; D015222:Sodium Channels / Q000187:drug effects* / Q000378:metabolism
D015222:Sodium Channels; D016222:Fibroblast Growth Factor 2; D012964:Sodium