title: Reevaluation of arrhythmias and alterations of the autonomic nervous activity induced by T-2 toxin through telemetric measurements in unrestrained rats.
abstract: This study was conducted to clarify and reevaluate the cardiac and autonomic nervous effects of T-2 toxin, which had been previously examined by several acute experiments, in unrestrained and conscious rats implanted with telemetric transmitters. Two groups of rats were given two subcutaneous injections of 0.1 and 0.5 mg/kg of T-2 toxin with an interval of 3 days. Two other groups of rat were pre-implanted with osmotic minipumps by which atropine (20 mg/kg/day) or propranolol (100 mg/kg/day) was continuously administered preceding subcutaneous injection of T-2 toxin (0.5 mg/kg). The present study demonstrated that T-2 toxin caused marked arrhythmias, such as second-degree atrioventricular (AV) block, sinus bradycardia, supraventricular extrasystole, and ventricular extrasystole, which were accompanied by a significant increase in heart rate and a significant decrease in total power and low- and high-frequency power of heart rate variability, during 3 days of observation after the toxin administration. However, the occurrence of arrhythmia with conduction disturbance such as second-degree atrioventricular blocks was markedly diminished by pretreatment with atropine, while the occurrence of ventricular extrasystole was augmented by atropine. The present study with the telemetric measurement elucidated and confirmed that T-2 toxin produced significant cardiac dysfunctions involving disturbance of the conduction pathway influenced by the autonomic nervous activity and also possible direct effects on cardiac myocytes.
authors.affiliation: Department of Comparative Pathophysiology, Division of Veterinary Medical Sciences, The University of Tokyo, Tokyo, Japan.
authors.forename: Suchitra
authors.initials: S
authors.lastname: Ngampongsa
authors.forename: Koichi
authors.initials: K
authors.lastname: Ito
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Kuwahara
authors.forename: Kentaro
authors.initials: K
authors.lastname: Ando
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Tsubone
mesh_terms: D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D001145:Arrhythmias, Cardiac / Q000139:chemically induced*; D001285:Atropine / Q000494:pharmacology; D001341:Autonomic Nervous System / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography; D004785:Environmental Pollutants / Q000633:toxicity*; D006321:Heart / Q000187:drug effects* / Q000294:innervation; D006329:Heart Conduction System / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D007279:Injections, Subcutaneous; D008297:Male; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013605:T-2 Toxin / Q000633:toxicity*; D013686:Telemetry
chemical_list: D000889:Anti-Arrhythmia Agents; D004785:Environmental Pollutants; D001285:Atropine; D011433:Propranolol; D013605:T-2 Toxin