Ca2+ influx stimulated by vasopressin is mediated by phosphoinositide hydrolysis in rat smooth muscle cells.
The mechanism of Ca2+ influx stimulated by arginine vasopressin (AVP) was studied in cultured rat smooth muscle cells. AVP stimulated 45Ca2+ influx even in the presence of nifedipine, a Ca2+ antagonist that inhibits voltage-dependent Ca2+ channel. NaF, a GTP-binding protein activator, mimicked the AVP-stimulated 45Ca2+ influx. The 45Ca2+ influx stimulated by a combination of AVP and NaF was not additive. The affinity of AVP receptor was decreased by guanosine 5'-O-(3-thiotriphosphate). Pertussis toxin failed to affect the AVP-stimulated 45Ca2+ influx. AVP did not stimulate cAMP production, but increased inositol trisphosphate generation. Both AVP-stimulated 45Ca2+ influx and inositol trisphosphate generation were inhibited by neomycin, a phospholipase C inhibitor, in a dose-dependent manner, and the patterns of both inhibitions were similar. These results suggest that, in rat smooth muscle cells, AVP-stimulated Ca2+ influx is mediated exclusively through phosphoinositide hydrolysis.
Kondo
K
K
First Department of Internal Medicine, Nagoya University School of Medicine, Japan.
Kozawa
O
O
Takatsuki
K
K
Oiso
Y
Y
D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D005459:Fluorides / Q000494:pharmacology; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D066298:In Vitro Techniques; D007295:Inositol Phosphates / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D009355:Neomycin / Q000494:pharmacology; D037342:Pertussis Toxin; D010716:Phosphatidylinositols / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011945:Receptors, Angiotensin / Q000378:metabolism; D017483:Receptors, Vasopressin; D013403:Sugar Phosphates / Q000378:metabolism*; D013873:Thionucleotides / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D007295:Inositol Phosphates; D010716:Phosphatidylinositols; D011945:Receptors, Angiotensin; D017483:Receptors, Vasopressin; D013403:Sugar Phosphates; D013873:Thionucleotides; D010566:Virulence Factors, Bordetella; D001127:Arginine Vasopressin; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate; D000242:Cyclic AMP; D037342:Pertussis Toxin; D009355:Neomycin; D005459:Fluorides; D002118:Calcium