Nonapeptide Hormones Oxytocin and Vasopressin Distinctly Regulate Ca_v1.2 L-type Calcium Channel Expression in Cardiomyocytes

Morishima, Masaki; Tahara, Shintaro; Wang, Yan; Kaku, Toshihiko; Ono, Katsushige

Background: The neurohypophyseal hormones oxytocin (OT) and [Arg8]-vasopressin (AVP) have recently been implicated in cardiac function. This study was designed to investigate actions of OT and AVP on regulation of the voltage-gated Ca2 channel in cardiomyocytes. Methods and Results: Cultured neonatal rat cardiomyocytes were stimulated with OT or AVP (10-8 M to 10-6 M) for 24-72 h, followed by real-time PCR and patch clamp studies. Although OT did not exert any modulatory effect on L-type Ca2 channel current, as a shortterm effect, stimulation of cardiomyocytes with OT but not AVP decreased the expression of Cav1.2 mRNA with a reduced L-type Ca2 channel current. A transcription factor CREB mRNA expression was down-regulated by OT treatment, although T-type Ca2 channels (Cav3.1, Cav3.2) were unaffected by OT or AVP. Conclusion: OT but not AVP down-regulates L-type Ca2 channel expression through the inhibition of CREB transcriptional, suggesting a novel mechanism of OT action in the cardiac electrophysiology.

OXYTOCIN -- Regulation; VASOPRESSIN regulation; PITUITARY hormones; CALCIUM channels regulation; HEART cells; TRANSCRIPTION factors; ELECTROPHYSIOLOGY

Journal of Arrhythmia, 2010, Vol 26, Issue 2, p111

1883-2148

Academic Journal

10.1016/S1880-4276(10)80015-8