title: Vascular vasopressin receptors mediate phosphatidylinositol turnover and calcium efflux in an established smooth muscle cell line.
abstract: Vasopressin-induced phosphatidylinositol turnover and mobilization of intracellular Ca2+ was studied using an established smooth muscle cell line (A-10). The cells were subcloned to ensure a monoclonal cell population. The accumulation of inositol mono-, di-, and tris-phosphates (IP1, IP2, and IP3, respectively), and the mobilization of intracellular Ca2+ were dependent on the time of incubation and the concentration of arginine vasopressin (AVP). IP1, IP2, and IP3 were significantly elevated after 15 sec and remained elevated for up to 2 hr. The concentrations of AVP required for half-maximal stimulation of IP1, IP2, and IP3 formation were 2, 12, and 4 nM, respectively. LiCl was required to observe the accumulation of inositol phosphates in response to AVP. Significant 45Ca2+ efflux was observed within 15 sec after exposure to AVP. By employing the vasopressin receptor subtype selective antagonists [d(CH2)5Tyr(Me)AVP, V1; d(CH2)5D-Tyr(Et)VAVP,V1/V2; d(CH2) 5D-IleVAVP,V2] and agonists [AVP, V1/V2; dDAVP, V2; dVDAVP, V2], we found that the vasopressin-induced stimulation of phosphatidylinositol turnover and 45Ca2+ efflux were mediated by receptors of the vascular V1 subtype. Pertussis toxin pretreatment partially inhibited vasopressin-induced phosphatidylinositol turnover. These data demonstrate that activation of V1 receptors of vascular smooth muscle cells resulted in enhanced phosphatidylinositol turnover and mobilization of intracellular Ca2+.
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001013:Aorta, Thoracic; D001127:Arginine Vasopressin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism; D037342:Pertussis Toxin; D010656:Phenylephrine / Q000494:pharmacology; D010716:Phosphatidylinositols / Q000378:metabolism*; D051381:Rats; D011945:Receptors, Angiotensin / Q000187:drug effects / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000502:physiology*; D017483:Receptors, Vasopressin; D014667:Vasopressins / Q000494:pharmacology*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D010716:Phosphatidylinositols; D011945:Receptors, Angiotensin; D011956:Receptors, Cell Surface; D017483:Receptors, Vasopressin; D010566:Virulence Factors, Bordetella; D014667:Vasopressins; D000804:Angiotensin II; D001127:Arginine Vasopressin; D010656:Phenylephrine; D037342:Pertussis Toxin; D002118:Calcium