Sudden severe dysrhythmias during anaesthesia can be life- threatening for the patient. We describe a case in which ventricular dysrhythmias and severe bradycardia occurred during dissection and mobilization of the deep lobe of the parotid gland during total parotidectomy under general anaesthesia. We believe that these dysrhythmias were caused by a trigemino- vagal reflex similar to the oculoc...

Transient episodes of fetal bradycardia (heart rate less than 110 bpm) are usually benign and typically result from increased vagal stimulation in the fetus. Causes of sustained fetal bradycardia include sinus bradycardia, blocked atrial bigeminy/trigeminy, high-degree atrioventricular block, and long QT syndrome. We present the case of a 34-year-old Caucasian patient referred to our department...

This study explored physiological mechanisms of diabetic dysfunction in baroreceptors and chemoreceptors-mediated hemodynamic responses, and cholinergic neurotransmission in 30-day diabetic rats (n = 14) and controls (n = 14). Basal hemodynamic data and vagal response to electrical stimulation and methacholine injection were also evaluated. Muscarinic receptors were characterized using a radiol...

BACKGROUND The regulator of G-protein signaling 5 (Rgs5), which functions as the regulator of G-protein-coupled receptor (GPCR) including muscarinic receptors, has a potential effect on atrial muscarinic receptor-activated IKA ch current. METHODS AND RESULTS In the present study, hearts of Rgs5 knockout (KO) mice had decreased low-frequency/high-frequency ratio in spectral measures of heart r...

The purpose of this study was to determine the relative magnitudes of the reflex effects mediated by cardiac receptors during anterior as opposed to inferoposterior ischemia of the left ventricle of the dog. Cessation of perfusion (coronary "occlusion") of the circumflex coronary artery (Cx) in 29 chloralose-anesthetized dogs with common carotids ligated (group I) resulted in significant bradyc...

In response to a brief vagal stimulus, the atrial rate initially slows, then transiently accelerates, and slows a second time. We determined the effects of three antagonists to two ionic channels on this characteristic triphasic pacemaker response. Brief bursts of vagal stimulation were delivered to anesthetized dogs, and atrial cycle lengths were recorded. Either barium, cesium, or UL-FS-49 wa...

Recent work suggests neurons can have different types of GABAA receptors that mediate phasic inhibitory post-synaptic currents (IPSCs) and tonic currents. This study examines the diversity of GABAergic synaptic currents in parasympathetic cardioinhibitory neurons that receive rhythmic bursts of GABAergic neurotransmission. Focal application of gabazine (25 μM) to cardiac vagal neurons in-vitro ...

produces the cardiac slowing, because cardiac glycosides can produce bradycardia even after bilateral severance of vagus nerves or under the effect of atropine (3, 4). Gold et al. (5, 6) suggested a direct bradycardiac action of cardiac glycosides on the heart muscle. However, the results on the effect of cardiac glycosides on the heart rate are still con troversial in the experiments with isol...