Hj. Zhong et C. Nurse, BASIC FIBROBLAST GROWTH-FACTOR REGULATES IONIC CURRENTS AND EXCITABILITY OF FETAL-RAT CAROTID-BODY CHEMORECEPTORS, Neuroscience letters, 202(1-2), 1995, pp. 41-44
Basic fibroblast growth factor (bFGF) and nerve growth factor (NGF) ar
e known mitogens and/or differentiation factors for cells of the sympa
thoadrenal lineage. Though carotid body (CB) chemoreceptors (type 1 ce
lls) are considered part of this lineage, their response to bFGF is un
known and so far they appear unresponsive to NGF in vitro. In this stu
dy we use whole-cell recording to investigate whether bFGF (and NGF) c
an influence the development of ionic currents in these chemoreceptors
, cultured from fetal (E18-19) rat pups. bFGF (10 ng/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 accom
panying increase in cell size, as indicated by whole-cell capacitance,
the Na+ current density was nonetheless increased by bFGF. Unlike con
trols, bFGF-treated type 1 cells readily fired action potentials follo
wing depolarization. These effects were not mimicked by NGF (100 ng/ml
) treatment. Since the carotid body is one of the most richly vascular
ized 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 ex
citability.