The Indian rupee gained by 21 paise to 45 rupees 50 paise against the American currency in the morning trade.This follows fresh selling of dollars by banks and corporates in view of weakness of dollar in overseas markets.In active trade at the Interbank Foreign Exchange or Forex market, the domestic unit opened higher at 45 rupees 58 paise per dollar against the Tuesday's close of 45 rupees 72 paise and firmed up to 45 rupees 50 paise before quoting at 45 rupees 56 paise.