The effects of pyrene exposure on exercise performance, muscle contraction, and mitochondrial O₂ consumption in the leopard frog (Rana pipiens)

Abstract

The present study exposed frogs to the PAH pyrene and measured exercise performance, muscle contractile ability, mitochondrial O₂ consumption, and membrane potential. Leopard frogs, Rana pipiens, were exposed for seven days in control or pyrene saturated water aquaria. Frogs were randomly placed into one of four groups: (i) pyrene-exposed exercised, (ii) control, exercised, (iii) pyrene-exposed, non-exercised, and (iv) control, non-exercised. Following the acute exposure, exercise duration, muscle contractile ability, blood gases and pH, glycogen levels, crossbridge formation and contractile length, and mitochondrial respiration were measured. The data revealed that pyrene exposure produced many adverse effects in Leopard frogs including significant reductions in exercise performance, muscle contractile ability, and alterations to muscle mitochondrial O₂ consumption and membrane potential. These data suggest that PAH exposure may limit survival for frogs in the wild by limiting foraging, mating, and predator avoidance behaviors.

Keywords:

• Frog
• Rana pipiens
• polycyclic aromatic hydrocarbons
• pyrene
• muscle contraction
• mitochondrial respiration

Acknowledgments

Grateful appreciation is expressed to Angelina Bonner for her assistance with the exercise performance, mitochondrial O₂ consumption, and membrane potential experiments. Partial funding was provided by a Bradley University Special Emphasis Faculty/Student Collaboration grant to EKS.