Tokyo stocks opened sharply lower Friday, weighed down by concern over the outlook for European economies after the European Central Bank decided to conduct in July its first interest rate hike in 11 years to tackle high inflation. In the first 15 minutes of trading, the 225-issue Nikkei Stock Average fell 325.32 points, or 1.15 percent, from Thursday to 27,921.21. The broader Topix index was down 17.82 points, or 0.91 percent, at 1,951.23. On the top-tier Prime Market, decliners were led by marine transportation, iron and steel, and service issues. At 9 a.m., the dollar fetched 134.37-38 yen …