Effects of 2,4-Dinitrophenol upon Oxygen Consumption and Ciliary Activity in the Ctenidia of Mytilus ∗

Abstract

Summary

1. The effects of 2,4-dinitro-phenol (DNP) upon oxygen consumption and ciliary activity in the excised ctenidia of Mytilus edulis were investigated. 2. The maximal stimulation of oxygen uptake was estimated to occur when the DNP was 5 × 10^-4 M. 3. Ciliary beat was increasingly inhibited as the concentration of DNP was raised. 50% inhibition was estimated at 4 × 10^-4 M DNP, and inhibition was complete in the presence of 7.7 × 10^-3 M DNP. 4. The possible role of DNP in uncoupling exergonic from endergonic processes receives support from the close coincidence of these effective concentrations. The close correspondence also suggests a single site of action for DNP.