Mitochondrial Swelling Induced by Plagus Murine Toxin.

It has been reported that the mouse and the rat are susceptible to the action of plague murine toxin, whereas the rabbit is not (1). The effect of this toxin on mitochondrial respiration varies with respect to the animal species and organ from which the mitochondria are isolated. The respiration of rat heart (1) as well as rat and rabbit liver mitochondria (2) is inhibited by the toxin. In contrast, the respiration of rabbit sarcosomes and rat brain mitochondria (1) is unaffected. It has been shown previously (2) that whereas plague murine toxin has little or no effect on the respiration of unaltered rabbit heart mitochondria, toxin can inhibit the respiration of these mitochondria when they first are disrupted by either deoxycholate or sonic vibration. This suggests that the rabbit heart mitochondrial membrane can exclude the toxin. Since it is believed (3) that at least one type of mitochondrial swelling depends upon increased permeability of the membrane that ceases short of osmotic rupture of the mitochondrion, an attempt was made (2) to determine whether some relationship exists between the effect of toxin on mitochondrial respiration and its effect on mitochondrial swelling. It was found that toxin induced swelling of rat heart mitochondria but was unable to swell rabbit heart and rat brain mitochondria. The aim of the research described herein is a-fold: (a) to extend the studies dealing with the effect of toxin on mitochondrial swelling to include liver mitochondria, (b) to demonstrate the specificity of mitochondrial swelling as induced by plague toxin, and (c) to study the mechanism of this toxin-induced swelling.