Effects of autonomic nervous system blockade on heart rate and P wave duration in anaesthetized wild-type and NPR-C knockout mice
A and B, representative ECG recordings in baseline conditions and following a combined intraperitoneal injection of atropine (1 mg kg−1) and propranolol (10 mg kg−1) to block the autonomic nervous system. C, summary of the effects of atropine and propranolol (injected at time = 0 min) on heart rate in NPR-C+/+ and NPR-C−/− mice. *P < 0.05 vs. NPR-C+/+ by Student's t test. D, summary of P wave duration at baseline and 30 min after injection of atropine and propranolol in NPR-C+/+ and NPR-C−/− mice. *P < 0.05 vs. baseline; +P < 0.05 vs. NPR-C+/+; data analysed by two-way ANOVA with Tukey's post-hoc test; n = 24 NPR-C+/+ mice and 19 NPR-C−/− mice for autonomic blockade studies. NPR, natriuretic peptide receptor.