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Identification and function of ryanodine receptor subtype 3 in non‐pregnant mouse myometrial cells
Author(s) -
Mironneau J.,
Macrez N.,
Morel J.L.,
Sorrentino V.,
Mironneau C.
Publication year - 2002
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2001.013046
Subject(s) - ryanodine receptor , extracellular , endoplasmic reticulum , endogeny , intracellular , transfection , immunostaining , receptor , medicine , biology , chemistry , endocrinology , microbiology and biotechnology , cell culture , biochemistry , immunohistochemistry , genetics
Subtype 3 of the ryanodine receptor (RYR3) is a ubiquitous Ca 2+ release channel which is predominantly expressed in smooth muscle tissues and certain regions of the brain. We show by reverse transcription‐polymerase chain reaction (RT‐PCR) that non‐pregnant mouse myometrial cells expressed only RYR3 and therefore could be a good model for studying the role of endogenous RYR3. Expression of RYR3 was confirmed by Western blotting and immunostaining. Confocal Ca 2+ measurements revealed that in 1.7 m m extracellular Ca 2+ , neither caffeine nor photolysis of caged Ca 2+ were able to trigger any Ca 2+ responses, whereas in the same cells oxytocin activated propagated Ca 2+ waves. However, under conditions of increased sarcoplasmic reticulum (SR) Ca 2+ loading, brought about by superfusing myometrial cells in 10 m m extracellular Ca 2+ , all the myometrial cells responded to caffeine and photolysis of caged Ca 2+ , indicating that it was possible to activate RYR3. The caffeine‐induced Ca 2+ responses were inhibited by intracellular application of an anti‐RYR3‐specific antibody. Immunodetection of RYR3 with the same antibody revealed a rather homogeneous distribution of fluorescence in confocal cell sections. In agreement with these observations, spontaneous or triggered Ca 2+ sparks were not detected. In conclusion, our results suggest that under conditions of increased SR Ca 2+ loading, endogenous RYR3 may contribute to the Ca 2+ responses of myometrial cells.