Shares of Targacept (NASDAQ:TRGT) fell 14% Tuesday after announcing that it will drop plans with AstraZeneca (NYSE:AZN) on creating a drug to treat major depressive disorder.Targacept (NASDAQ:TRGT) has potential upside of 132.1% based on a current price of $5.6 and an average consensus analyst price target of $13.Targacept should find initial resistance at its 50-day moving average (MA) of $6.52 and further resistance at its 200-day MA of $13.02.