Figure 8. Anoxia caused bradycardia due to a direct effect on the heart.

WT mice exposed to anoxia developed bradycardia (n = 5). Pretreatment with atropine (1 mg/kg, i.p.) caused an increase in baseline heart rate, but did not prevent this bradycardia (n = 5), indicating that bradycardia was not due to increased vagal output. Scn1a^R1407X/+ mice also developed bradycardia in response to anoxia (n = 6).