Fig. 5: BnOCPA does not affect heart rate or blood pressure.
a Examples of heart rate (HR) and b arterial blood pressure traces from a urethane-anaesthetised, spontaneously breathing rat showing the effects of adenosine (1 mg kg−1), BnOCPA (8 µg kg−1) and CPA (6 µg kg−1). Grey diamonds reflect saline flushing of the femoral vein catheter. Insets are expanded HR and blood pressure responses to adenosine and BnOCPA (black and blue traces, respectively; boxed regions in a and b). Scale bars measure: HR, 200 BPM and 6 s; blood pressure, 40 mm Hg and 6 s. c, d Summary data for 4 rats where each rat is shown as a different symbol with the means (± SEM, light grey bars) connected. One-way RM ANOVA for: c HR, Greenhouse-Geisser corrected F(2.33, 7.00) = 68.27, P = 2.07 × 10−5; d mean arterial blood pressure (MAP), Greenhouse-Geisser corrected F(1.84, 5.52) =10.51, P = 0.014; with the following Bonferroni post hoc comparisons: The resting HR of 432 ± 21 BPM was significantly reduced to 147 ± 12 BPM (~66%, P = 2.76 × 10−11) by adenosine. BnOCPA had no effect on HR (~6%, 442 ± 20 vs 416 ± 21 BPM; P = 1) but prevented the bradycardic effects of adenosine (P = 2.71 × 10−9 vs adenosine) when co-injected (mean change 51 ± 4 BPM; ~12%; P = 0.67). CPA significantly decreased HR (from 408 ± 17 to 207 ± 29 BPM; ~50%, P = 1.85 × 10−8), a decrease that was not different to the effect of adenosine (P = 0.12), but was significantly different to the effect of both BnOCPA (P = 9.00 × 10−9) and adenosine in the presence of BnOCPA (P = 6.69 × 10−7). The resting MAP (86 ± 9 mm Hg) was significantly reduced by adenosine (~47%, 46 ± 4 mm Hg; P = 0.001). BnOCPA had no effect on its own on MAP (88 ± 11 vs 85 ± 13 mm Hg; P = 1) and did not prevent adenosine in lowering MAP to a value similar to adenosine on its own (51 ± 4 mm Hg; P = 1 vs adenosine; P = 0.012 vs BnOCPA alone). CPA significantly decreased MAP (from 83 ± 8 to 51 ± 5 mm Hg; P = 0.017), a decrease that was not different to the effect of adenosine in the absence or presence of BnOCPA (P = 1 for both). ns, not significant; **, P < 0.02; ***, P < 0.001; ****, P < 0.0001. Source data are provided as a Source Data file.
