The Sensex fell by over 141 points or 0.80 per cent in opening trade today on profit booking and a weak trend on other Asian bourses. The 30-share index, which had gained nearly 179 points in the previous two sessions, was down 141 points to 17,418 points in opening trade. Stocks of information technologies, metals and oil and gas sectors were under pressure, pulled the Sensex down. The wide-based National Stock Exchange index Nifty alsodeclined by 47 points to 5,231 points. Marketmen said profit-booking by funds and retail investors and a weak trend in Asian markets mainly pulled the benchmark Sensex down.