Methods in molecular biology
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Mitochondria are considered as the main source of reactive oxygen species (ROS) in the cell. For this reason, they have been recognized as a source of various pathological conditions as well as aging. Chronic increase in the rate of ROS production is responsible for the accumulation of ROS-associated damages in DNA, proteins, and lipids, and may result in progressive cell dysfunctions and, in a consequence, apoptosis, increasing the overall probability of an organism's pathological conditions. ⋯ In this chapter, we describe a relation between mitochondrial membrane potential and the rate of ROS formation. We present different methods applicable for isolated mitochondria or intact cells. We also present experiments demonstrating that a magnitude and a direction (increase or decrease) of a change in mitochondrial ROS production depends on the metabolic state of this organelle.
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Cocaine self-administration provides a methodology allowing researchers to study changes in distinct aspects of drug-taking behavior that model behaviors observed in drug addicts. Traditionally, self-administration schedules were designed to independently study changes in drug-taking behaviors (e.g., rate of responding, reinforcing efficacy, etc.). The threshold self-administration procedure was developed to measure two distinct dependent measures within the same experimental session that are important in the study of drug addiction: the maximal price an animal expends to self-administer cocaine and an animal's preferred level of cocaine consumption when available at a low behavioral cost.
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Osteoarthritis (OA) is one form of degenerative joint disease characterized by progressive loss of articular cartilage, decreased function and is frequently accompanied by chronic pain. Given the success of arthroplasty as a treatment for late-stage OA, there is considerable interest in developing therapies pertaining to the management of pain associated with OA as well as therapies designed to slow or reverse the progression of the disease. ⋯ Here, we describe a model of OA-related pain in which progressive joint destruction is induced by injection of monosodium iodoacetate into the articular space of the knee of the rat. Further, we describe three different methods to measure pain-related behaviors in this model: hind limb weight bearing, primary mechanical hyperalgesia, and hind limb grip strength.