Fig. 1. In vivo  mean arterial blood pressure (MAP), heart rate (HR), and cardiac output (CO) after administration of 2 mg/kg succinylcholine at time = 0 min for (1) individual MHS animals (MHS 1–5); (2) MHS animals pretreated with 2.5 mg/kg dantrolene (MHS D1 and 2); (3) MHS animals pretreated with 1 mg/kg vecuronium (MHS V1–3); and (4) normals (N 1–5). It can be observed that MAP and CO decreased significantly in MHS and MHS D, but not in MHS V or normals (N). MHS 4 and MHS D2 both required epinephrine therapy at 5 and 7 min, respectively (indicated by number sign). A decrease of MAP and CO in MHS V1 was considered to be caused by an air embolus (indicated by asterisk).