Effect of Flow Rate and PH on Muscle Acidosis

Sng is a prominent complaint in Taiwanese people with low back pain. "Sng" is created to represent this Taiwanese word- 痠. Based on our preliminary data, sng was one of the most common complaints in patients with chronic low back pain (CLBP) and also one of the most common indication for lumbar spine operations. Back sng is not adequately relieved by pain-killers or even by the lumbar spine operations. By using functional MRI and questionnaires, our preliminary study demonstrated that sng is different from pain in the level of brain perception and the level of subjective concept. It is very likely that sng has its own unique nerve pathway other than pain. The subjective feeling of sng is very similar to sour in taste, so it is likely that acidosis may be involved in the process of sng sensation, especially in the muscle. Delayed onset muscle soreness is a well-known example, and the soreness is dependent on the proton-sensing neurons. Indeed, substantial evidences showed that up to 80% muscle afferents are acid-sensitive but not nociceptors. Therefore, the investigators propose that sng is the perception in the brain when the tissue acidosis is sensed by the somatosensory system, and "sng-ception" is created to indicate the sensation of tissue acidosis. However, the causal connection between the peripheral sngception and the central brain perception of sng is not established. The objective of this proposal is to establish the causal connection between peripheral muscle acidosis and the central brain sng perception. My central hypothesis is that acidosis-evoked sensation in the muscles will cause a central sng perception in the brain. This hypothesis is based on our previous studies that showed sng is different from pain in terms of subjective responses, brain activation areas and clinical impacts. To achieve this goal, two specific aims will be pursued 1. to determine if an acid solution will evokes sng response, and, 2.determining the correlation between the rate of drug application and muscle Sng. Successful establishment of the casual connection between the peripheral muscle acidosis and the central brain sng perception will lead to a more comprehensive understanding of sng mechanism and the potential medication development.