Figure 2.
Influence of SR 141716A on the phenylbiguanide-induced reflex bradycardia in urethane-anaesthetized rats pre-treated with propranolol (0.3 μmol kg−1). Animals were given three or four increasing doses of phenylbiguanide (1, 3, 10 and 30 μg kg−1) with sufficient time between injections for full recovery to pre-injection parameters. Determination of the phenylbiguanide dose-response curve was repeated 10 min after the exposure to SR 141716A (3 μmol kg−1). Means±s.e.mean of n=3–6 rats. Bradycardia was expressed as a percentage of the basal heart rate immediately before the injection of phenylbiguanide.