Response of cytosolic Ca2+ to hypercapnic acidosis in cultured glomus cells of the adult rabbit carotid body.
The characteristics underlying the response of cytosolic Ca2+ ([Ca2+]i) to hypercapnic acidosis in clusters of cultured glomus cells of the adult rabbit carotid body were evaluated using fura-2 microscopic fluorometry. Application of CO2 by bubbling through both superfusions of bicarbonate-buffered saline and HEPES-buffered saline produced a rapid and sustained increase in [Ca2+]i. The [Ca2+]i response increased correspondingly with a rise in concentrations of CO2 to 20% but at a point between 20 and 50% adapted to CO2 and it decreased its linear assent. The hypercapnic acidosis-induced increase of [Ca2+]i was diminished by removing external Ca2+. Also the [Ca2]i response was reduced in dose-dependent fashion by the addition of the voltage-gated Ca2+ channel blocker D600. An additional response of [Ca2+]i to acetate was also diminished by Ca2+ removal. These results suggest that the [Ca2+]i response to hypercapnic acidosis involves an influx of external Ca2+ through voltage-gated Ca2+ channels.
Department of Physiology, Akita University School of Medicine, Japan.
M
M
Sato
D000138:Acidosis / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002344:Carotid Body / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism*; D016257:Fura-2; D005711:Gallopamil / Q000494:pharmacology; D006935:Hypercapnia / Q000378:metabolism*; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology; D008856:Microscopy, Fluorescence; D011817:Rabbits
D002121:Calcium Channel Blockers; D005711:Gallopamil; D002118:Calcium; D016257:Fura-2