Basic FGF localization in rat carotid body: paracrine role in O2 -chemoreceptor survival.
Exposure of perinatal rat carotid body (CB) O2-chemoreceptors to basic fibroblast growth factor (bFGF) or hypoxia in vitro increases mitotic activity. Using double-label immunofluorescence, we localized bFGF and its receptor (FGFR) to tyrosine hydroxylase-positive (TH+) chemoreceptors in vitro; bFGF immunoreactivity also localized to chemoreceptors in CB tissue sections. Mitotic activity, measured as percentage TH+ cells that took up bromodeoxyuridine, was relatively constant ( approximately 29%) in normoxic (20% O2) cultures grown with or without bFGF neutralizing antibody (nAb). However, the number of surviving chemoreceptors was significantly reduced in nAb-treated cultures. Under chronic hypoxia (6% O2), the presence of nAb significantly reduced chemoreceptor survival to approximately 70% of control, without affecting mitotic activity. Thus, autocrine/ paracrine actions of endogenous bFGF may help promote CB chemoreceptor survival.
Paciga
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Department of Biology, McMaster University, 1280 Main Street West Hamilton, Ontario, Canada.
Nurse
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CA
D000818:Animals; D000831:Animals, Newborn; D000906:Antibodies / Q000494:pharmacology; D001973:Bromodeoxyuridine; D002344:Carotid Body / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D016923:Cell Death / Q000187:drug effects / Q000502:physiology*; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005346:Fibroblast Growth Factors / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D000860:Hypoxia / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D010100:Oxygen / Q000378:metabolism*; D019899:Paracrine Communication / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D017468:Receptors, Fibroblast Growth Factor / Q000378:metabolism; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
D000906:Antibodies; D017468:Receptors, Fibroblast Growth Factor; D005346:Fibroblast Growth Factors; D014446:Tyrosine 3-Monooxygenase; D001973:Bromodeoxyuridine; D010100:Oxygen