Figure 3.

Cardiovascular responses to CGS21680 (10⁻¹¹ – 10⁻⁷ mol kg⁻¹ i.v.) in anaesthetized guinea-pig; in the absence of pretreatment and in the presence of L-NAME (50 mg kg⁻¹ i.v.), methylene blue (10 mg kg⁻¹ i.v) or ZM 241385 (1 mg kg⁻¹ i.v). Each point in the curves is the mean±s.e. of 4 – 6 experiments; ^*P⩽0.05. Values are reported as per cent of resting mean blood pressure (BP) or heart rate (HR) just prior to starting the agonist dose-response curve: 48.3±8.5 mmHg and 371.7±15.0 beats min⁻¹ (control); 65.6±4.4 mmHg and 368.5±14.2 beats min⁻¹ (L-NAME-treated); 70.0±6.3 and 390±11.6 beats min⁻¹ (methylene blue-treated); 65.6±4.2 and 375.5±11.6 beats min⁻¹ (ZM 241385-treated).