2017 年 67 巻 2-4 号 p. 129-135
We analyzed the effects of halothane as an inhalational anesthetic agent on electrocardiogram (ECG) parameters in C57/BL6 mice. Following induction of anesthesia using 2% halothane, the ECGs showed a regular
pattern and the heart rate (HR) was within an acceptable range (~500 bpm). The HR decreased with increasing
halothane concentration in a concentration-dependent fashion.
The frequency domain analysis showed that the high-frequency (HF) component decreased and the lowfrequency (LF) component increased in a concentration-dependent fashion. Therefore, the LF/HF ratio increased with increasing halothane concentration, suggesting effects on the autonomic nervous system.
We analyzed the pharmacological response to sympathetic blockade with propranolol, a typical adrenergic β-blocker, under halothane anesthesia. Propranolol administration resulted in a decreased HR; interestingly, intraperitoneal injection of propranolol (120 μg/kg body weight) resulted in arrhythmia (sick sinus syndrome) during anesthesia with 3% halothane.
Our results indicate the importance of selecting a suitable anesthetic agent for C57/BL6 mice in pharmacological studies.