Fluoro-fatty acids and the impairment of cardiac function in the rat in vivo and in vitro.

Dichapetalum toxicarium seeds contain long chain fluoro-fatty acids, particularly fluoro-oleic acid, which in doses as low as 10 mg/kg can cause death. We have used the rat heart both in vivo and in vitro to assess the cardiovascular effects of various doses of the fluoro-oleic acid extract of the seeds of Dichapetalum toxicarium. Intraperitoneal administration of 0.25 ml of seed extract solution/kg body weight (estimated to be equivalent to 10 mg fluoro-oleic acid/kg body weight) or 0.5 ml/kg body weight (equivalent to 20 mg fluoro-oleic acid/kg body weight) resulted in death in all animals (n = 6 in each group). The mean time from administration to death was 36.4 +/- 4 h and 21.0 +/- 2 h, respectively. Death was attributable to severe bradycardia which developed progressively throughout the experiment. Thus, during the first 6 h, heart rate fell by 32.2% from 450 +/- 7 beats/min to 305 +/- 36 beats/min (p less than 0.01) in the 0.25 ml/kg group and by 66 +/- 10% to 150 +/- 20 beats/min (p less than 0.001) in the 0.5 ml/kg group. Administration of the extract solution alone or oleic acid alone (equivalent to 0.5 ml/kg seed extract) to control rats had no effect. Investigating the effects of the seed extract in vitro, hearts (n = 6 in each group) were perfused with buffer containing 0.5 ml/l seed extract (equivalent to 20 mg fluoro-oleic acid/l) or with buffer containing extract solution alone.(ABSTRACT TRUNCATED AT 250 WORDS)