Ultrastructural and functional changes of turkey myocardium induced by in vitro exposure to cyclopiazonic acid

Isolated turkey papillary muscles were acutely exposed to 0 or 6 mu A mu g/mL of cyclopiazonic acid (CPA) mycotoxin. Seven parameters of in vitro papillary muscle performance were significantly decreased. The performance criteria were maximum weight a muscle could lift (P(o)), work, maximum contraction and relaxation velocity, and times to initiation, peak, and completion of contractions. Calcium and adenosine triphosphate (ATP) availability appear to be responsible, in part, for these altered performances. Electron photomicrographs demonstrated that CPA-exposed muscles had increased numbers of swollen or lysed mitochondria. This study provides additional evidence that, at this exposure level, in vitro cardiac muscle performance is irreversibly decreased and mitochondrial morphology is altered.</.