1. Pioglitazone Attenuates Acute Cocaine Toxicity in Rat Isolated Heart
- Author
-
Sarah Bern, Guido Digregorio, Lucas B. Edelman, Mariann R. Piano, Douglas L. Feinstein, Bocheng Lin, Guy L. Weinberg, and Richard Ripper
- Subjects
medicine.medical_specialty ,Lusitropy ,business.industry ,Carbohydrate metabolism ,Pharmacology ,Contractility ,Anesthesiology and Pain Medicine ,medicine.anatomical_structure ,Endocrinology ,Internal medicine ,Toxicity ,Respiration ,Vascular resistance ,Medicine ,business ,Pioglitazone ,Heart metabolism ,medicine.drug - Abstract
Background The authors tested whether cocaine depresses mitochondrial acylcarnitine exchange and if a drug that enhances glucose metabolism could protect against cocaine-induced cardiac dysfunction. Methods Oxygen consumption with and without cocaine was compared in rat cardiac mitochondria using octanoylcarnitine (lipid) or pyruvate (nonlipid) substrates. Isolated hearts from rats with or without a pioglitazone-supplemented diet were exposed to cocaine. Results The 0.5 mM cocaine inhibited respiration supported by octanoylcarnitine (82 ± 10.4 and 45.7 ± 4.24 ngatomO min⁻¹ · mg⁻¹ · protein ± SEM, for control and cocaine treatment, respectively; P < 0.02) but not pyruvate-supported respiration (281 ± 12.5 and 267 ± 12.7 ngatomO min⁻¹ · mg⁻¹ · protein ± SEM; P = 0.45). Cocaine altered contractility, lusitropy, coronary resistance, and lactate production in isolated heart. These effects were each blunted in pioglitazone-treated hearts. The pioglitazone diet attenuated the drop in the rate-pressure product (P = 0.002), cocaine-induced diastolic dysfunction (P = 0.04), and myocardial vascular resistance (P = 0.05) compared with that of controls. Lactate production was higher in pretreated hearts (P = 0.008) and in ventricular myocytes cultured with pioglitazone (P = 0.0001). Conclusions Cocaine inhibited octanoylcarnitine-supported mitochondrial respiration. A pioglitazone diet significantly attenuated the effects of cocaine on isolated heart. The authors postulate that inhibition of acylcarnitine exchange could contribute to cocaine-induced cardiac dysfunction and that metabolic modulation warrants additional study.
- Published
- 2011
- Full Text
- View/download PDF