Fig. 2. Effects of (A) acetylcholine (ACh) and (B) dopamine (DA) on arterial pressure in each of the anterior median artery (AMA), anterior lateral artery (ALA) and fifth lateral artery (LA5) preparations without heartbeat (see Materials and methods). Arterial pressure of LA5 was decreased by perfusion with serotonin (5-HT) to accentuate the effects of ACh on pressure of the artery. Bars represent periods of agent application. It was confirmed that an agent solution reached the preparation in approximately 30 s after the start of perfusion.