The rupee today depreciated by 10 paise against the dollar in opening trade on fears that capital inflows would be impacted adversely after the Reserve Bank tightened the guidelines for external commercial borrowings. At the Interbank Foreign Exchange (Forex) market, the domestic unit traded at 46.63 a dollar. It had closed 14 paise higher at 46.53 against the dollar in yesterday's volatile trading session. The Reserve Bank, yesterday, tightened the guidelines for external commercial borrowings by withdrawing relaxations provided to companies to raise money from overseas debt markets.