Tokyo stocks opened slightly lower Thursday, as sentiment was dampened by an overnight fall of the U.S. Dow Jones index. In the first 15 minutes of trading, the 225-issue Nikkei Stock Average dropped 112.48 points, or 0.31 percent, from Wednesday to 36,114.00. The broader Topix index was down 2.28 points, or 0.09 percent, at 2,526.94. On the top-tier Prime Market, decliners were led by electric power and gas, pharmaceutical and service issues. At 9 a.m., the U.S. dollar fetched 147.58-59 yen compared with 147.45-55 yen in New York and 147.78-80 yen in Tokyo at 5 p.m. Wednesday. The euro was qu…