Ehna hydrochloride

Cell density at 2 × 10⁴ cells/mL of Caco-2 cells was cultured in DMED supplemented with 1% fetal bovine serum, at 37 °C in 5% CO₂ and 100% humidity. Cell viability was measured after treatment at 96 h through trypan-blue analysis in Caco-2 cells. EGCG was purchased from Sigma-Aldrich (St. louis, MO, USA). VDN was purchased from Toronto Research Chemicals (Toronto, ON, Canada). Bay 41-2272 was purchased from Enzo Life Sciences (Exeter, UK). Anti-PKCδ antibody was purchased from abcam. PDE1 inhibitor 8-Met-IBMX, PDE4 inhibitor rolipram, and PDE5 inhibitor VDN were purchased from Sigma-Aldrich. PDE2 inhibitor EHNA hydrochloride was purchased from abcam.

Nifedipine, nisoldipine, nitrendipine, nilvadipine, and isradipine were obtained from Tokyo Chemical Industry (Tokyo, Japan) and Wako Pure Chemical Industries (Osaka, Japan). PSB-1115 was purchased from Santa Cruz Biotechnology. Amlodipine besylate (amlodipine), adenosine deaminase (ADA), N6-cyclopentyladenosine (CPA), forskolin, and adenosine were purchased from Sigma (St. Louis, MO). CGS21680, IB-MECA, and EHNA hydrochloride (EHNA) were obtained from Abcam (Cambridge, UK). BAY60-6583 was purchased from Tocris Bioscience (Bristol, UK). The compound library consisting of 1,241 existing medicines was a kind gift from LTT Bio-Pharma Co., Ltd (Tokyo, Japan).