Tokyo stocks opened lower Tuesday as investors locked in gains after the Nikkei index closed at an all-time high above the 40,000 line the previous day. In the first 15 minutes of trading, the 225-issue Nikkei Stock Average fell 82.08 points, or 0.20 percent, from Monday to 40,027.15. The broader Topix index was down 6.09 points, or 0.23 percent, at 2,700.19. On the top-tier Prime Market, decliners were led by warehousing and harbor transportation service, pharmaceutical and metal product issues. At 9 a.m., the U.S. dollar fetched 150.45-47 yen compared with 150.48-58 yen in New York and 150.3…