Medetomidine, an .ALPHA.2-Adrenergic Agonist, Activates Cardiac Vagal Nerve Through Modulation of Baroreflex Control

Dexmedetomidine and Clonidine Inhibit Ventricular Tachyarrhythmias in a Rabbit Model of Acquired Long QT Syndrome

“…12 Shimizu et al reported that medetomidine, a selective α-2 AR agonist, modifies the cardiac autonomic state not only by suppressing cardiac noradrenaline release but also by activating vagal acetylcholine release. 13 In the present study, an increase in BP was attenuated by dexmedetomidine but not by clonidine ( Table 1). The difference between them in agonist-binding mode is that dexmedetomidine is almost a full agonist and clonidine is a partial agonist, which may explain the variability in the hemodynamic response.…”

Central vagal activation by alpha2‐adrenergic stimulation is impaired in spontaneously hypertensive rats

“…These results are supported by a previous study from our laboratories, in which intravenous medetomidine did not affect the vagal nerve stimulation-induced ACh release in rabbit right atrium (Shimizu et al 2012). These results are supported by a previous study from our laboratories, in which intravenous medetomidine did not affect the vagal nerve stimulation-induced ACh release in rabbit right atrium (Shimizu et al 2012).…”

“…A previous study from our laboratories using anaesthetized rabbits has indicated that intravenous administration of an a 2 -adrenergic agonist medetomidine activates the cardiac vagal nerve (Shimizu et al 2012). In that study, a cardiac microdialysis technique was applied to monitor the changes in myocardial interstitial ACh levels in the right atrial wall near the sinoatrial node.…”

Effect of Dexmedetomidine on the Corrected QT and Tp-e Intervals during Spinal Anesthesia

“…The receptor suppresses its own adrenal release from the terminal reticulum to the effecter, including the brain system, vasculature, and the heart, achieving sedation, analgesia, decreased blood pressure and bradycardia 3. Alpha-2-adrenoreceptor agonist modifies the cardiac autonomic state not only by suppressing cardiac noradrenaline release, but also by activating vagal acetylcholine release 24,25. Therefore dexmedetomidine is probably preferable for vulnerable patients with a prolonged QTc interval, especially when acceleration of the sympathetic nervous system is anticipated in the operating room.…”