Dr. Sluka's laboratory studies the peripheral and central mechanisms of chronic musculoskeletal pain. These studies primarily involve the use of animal models of muscle pain developed and characterized in Dr. Sluka's laboratory. Current projects are aimed at deciphering the role of descending facilitation from the medulla in initiating and maintaining chronic muscle pain. These studies are examining the neurotransmitters and receptors that mediate the hyperalgesia associated with musculoskeletal pain using behavioral pharmacology, immunohistochemistry, and in vivo microdialysis.
We are further examining the role of muscle fatigue in pain by examining if muscle fatigue enhances the development of muscle hyperalgesia; if there is increased muscle fatigue after development of muscle hyperalgesia; and the central and peripheral mediators that are involved in the fatigue. These studies utilize behavior pharmacology, histology, and standard neurochemical analysis.
In the peripheral nervous system, we are examining the role of peripheral ion channels (acid sensing ion channels (ASIC) and TRPV1) in the development and maintenance of musculoskeletal pain. Ion channels are particularly important for sensation of the microenvironment after tissue injury sensing decreases in pH and are modified by inflammatory mediators. The role of these channels in development and maintenance of inflammatory and non-inflammatory muscle hyperalgesia is being assessed using genetic manipulation of the ion channels (knockout, viral vector expression, viral vector knockdown), behavioral assessment, immunohistochemistry, real-time PCR, and ELISAs.
Dr. Sluka's laboratory has also been studying the neurobiology of TENS analgesia using an animal model of TENS to decipher the neurotransmitters, receptors, and anatomical sites that TENS utilizes to produce analgesia. Preclinical studies have begun to analyze combined pharmacological treatments with TENS to enhance effectiveness of the treatment in animals.
Dr. Sluka's laboratory has recently begun to translate experiments from the animal to the human subjects by examining effects of TENS on a variety of outcome measures in people with OA. These studies will begin to decipher the appropriate measures to use to assess TENS effectiveness on pain. We have also begun (in collaboration with Drs. Frey Law, Lars Arendt-Nielsen, Thomas Graven-Nielsen) to develop a human experimental pain model using infusion of acidic buffer into muscle. These studies directly developed out of our experiments in animals that show development of hyperalgesia after injection of acid into muscle, and activation of ASICs.