WASHINGTON (AP) — Federal regulators have approved an appetite-suppressing implant designed to treat obesity by zapping nerves that connect the stomach and the brain.The Maestro Rechargeable System uses electrodes implanted in the abdomen to stimulate the vagus nerve, which signals to the brain that the stomach is empty or full. Patients and doctors can adjust the device settings using external controllers.Shares of EnteroMedics rose in trading Wednesday after the Food and Drug Administration said it approved the device for certain patients who are severely obese. It’s the first medical device approved for obesity since the agency’s 2007 approval of a gastric band from Ethicon.The FDA approved the device for patients 18 and older who have been unable to lose weight via a supervised weight-loss program and have a body mass index of 35 to 40 with one other obesity-related health condition, such as diabetes.