Ca2+ release in cultured rat epididymal cells during hypoosmotic swelling.
Microfluorimetric studies were carried out to investigate the effects of hypoosmotic swelling on intracellular Ca2+ concentration ([Ca2+]i) in single rat epididymal cells. In Ca(2+)-free solution containing 50 mumols/l ethylenebis(oxonitrilo)tetraacetate (EGTA) hypoosmotic swelling (-160 mosmol/l) induced a transient rise in [Ca2+]i which was either monophasic, biphasic or oscillatory. The [Ca2+]i responses to repeated hypoosmotic stimulations followed a decremental pattern. However, if 2.5 mmol/l Ca2+ was admitted during the recovery period between successive stimulations, the second and the third [Ca2+]i responses were slightly greater than the first. Increasing the change in osmolarity from -14 +/- 1.0 to -154 +/- 1.5 mosmol/l increased the rise in [Ca2+]i but reduced the [Ca2+]i response to subsequent ionomycin stimulation (4 mumols/l). The swelling- and the ionomycin-induced rises in [Ca2+]i followed a reciprocal pattern. It was suggested that intracellular Ca2+ release in response to cell swelling in the epididymal epithelium might play a role in cell volume regulation and the control of epididymal fluid osmolarity.
Leung
A Y
AY
Department of Physiology, Faculty of Medicine, Chinese University of Hong Kong, Shatin.
Wong
P Y
PY
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D004533:Egtazic Acid / Q000494:pharmacology; D004822:Epididymis / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D007038:Hypotonic Solutions; D015759:Ionomycin / Q000494:pharmacology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013050:Spectrometry, Fluorescence
D007038:Hypotonic Solutions; D004533:Egtazic Acid; D015759:Ionomycin; D002118:Calcium