Adrenergic cardiovascular actions in rats as affected by dichloromethane exposure.

Dichloromethane sensitizes the myocardium to arrhythmia development in response to catecholamines. The effects of acute dichloromethane exposure (3.1, 6.2 or 12.4 mmol/kg) on cardiovascular actions of epinephrine (1 or 4 micrograms/kg iv) and norepinephrine (2 or 10 micrograms/kg iv) in the urethane-anaesthetized rat model was investigated. Hypertensive epinephrine effects as well as reflex bradycardia after epinephrine and norepinephrine injections were augmented in dichloromethane-exposed rats. Moreover we observed an enhanced negative dromotropic epinephrine action. The transient T-wave elevation after catecholamine injection was markedly increased in animals treated with 12.4 mmol/kg dichloromethane. The results show that dichloromethane exposure modifies cardiovascular actions after catecholamine administration. The release by dichloromethane of endogenous catecholamines could play a role in the manifestation of these effects.