Bradykinin-responsive cells of dorsal root ganglia in culture: cell size, firing, cytosolic calcium, and substance P.
1. We analyze bradykinin-sensitive cells of the mouse dorsal root ganglion in culture from the viewpoints of cell size, electrical responses, and Ca2+ concentration change due to bradykinin and immunocytochemistry of substance P. 2. Sixteen percent of cells in the cell group 26-30 microns in diameter fired in response to 10 microM bradykinin. None of other cell groups showed a firing response to bradykinin. 3. We measured a cytosolic Ca2+ change due to bradykinin using a Ca(2+)-sensitive fluorescent dye, Fura 2. The rapid rise (peak time, 20 sec) in the Ca2+ concentration was ascribed to Ca2+ release from intracellular Ca2+ stores. The profound change in the Ca2+ concentration was observed again in the cell group 26-30 microns in diameter. Seventeen percent of cells in this group increased the Ca2+ concentration by approximately seven times that at resting level. 4. Among cells which increase Ca2+ concentration responding to bradykinin, 83% of them contain substance P (an immunocytochemical study). 5. We conclude that 16-17% of the cell group 26-30 microns in diameter of the dorsal root ganglia in culture are polymodal nociceptors and respond to bradykinin.
Kano
M
M
Laboratory for Photobiology, Institute for Physical and Chemical Research (RIKEN), Miyagi, Japan.
Kawakami
T
T
Hikawa
N
N
Hori
H
H
Takenaka
T
T
Gotoh
H
H
D000818:Animals; D001920:Bradykinin / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism; D004594:Electrophysiology / Q000379:methods; D016257:Fura-2; D005727:Ganglia, Spinal / Q000166:cytology / Q000502:physiology*; D007150:Immunohistochemistry; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D013050:Spectrometry, Fluorescence; D013373:Substance P / Q000032:analysis / Q000378:metabolism*
D013373:Substance P; D001920:Bradykinin; D002118:Calcium; D016257:Fura-2