Relationship between the percentage reduction from the baseline values of cardiac output (CO, □), fundus pulsation amplitude (FPA, •), and exhaled NO (exhNO, ◊), and the plasma concentrations of l-NMMA from study 1. Results are presented as means±s.d., n=7. The Emax model (solid lines) provided a good fit for the effect of the drug on all the three dynamic parameters as indicated by the high coefficients of correlation (r2) and model selection criteria (MSC).