 This study is designed to assess the effect of sugammadex, neostigmineglycopyrrolate and spontaneous reversal of a moderate rocuronium-induced neuromuscular blockade on regional lung ventilation. This is a randomized, controlled, parallel-group double blind trial in rats. A total of 18 adult male Sprague-Dawley rats will be used, 6 in each treatment group. The animals will be randomized in one of three groups, in a 1:1:1 ratio. This randomization will be performed according to a computer-generated randomization list. The first group will receive neostigmineglycopyrrolate. The second group will receive sugammadex. The third group will receive water for injection. Reversal agents will be administered at a train-of-four TOF of 0.5, as measured with AMG. 