Utilizing molecular details of the pain system to illustrate biochemical principles.

To capture student interest and show clinical relevance, molecular details from the pain system can be used as supplemental examples to basic biochemistry lectures. Lecture topics include glutamate, substance P, calmodulin-dependent protein kinase II, synaptic proteases, calcitonin gene-related peptide, and neuronal protein synthesis. These topics are utilized to illustrate basic biochemical issues and are linked to pain-related topics such as pain transmission, synaptic plasticity, long-term potentiation, and central sensitization. For analysis, a brief survey was administered to evaluate student attitudes toward a representative lecture segment. Survey results support the premise that utilizing the pain system is an effective tool to engage chiropractic students during basic biochemistry lectures.

Central neuronal plasticity, low back pain and spinal manipulative therapy.

OBJECTIVE: Recent experimental evidence demonstrating neuronal/synaptic plasticity and, in particular, long-term potentiation (LTP) and long-term depression (LTD) in spinal neurons is reviewed. The implications of these studies for possible mechanistic explanations of low back pain and its remediation by spinal manipulative therapy (SMT) are explored. Brief descriptions of LTP and LTD and elaboration of the key roles of calcium, glutamate, and glutamate receptors in LTP/LTD are provided as separate appendices. DATA SOURCES: The referenced articles regarding LTP/LTD in spinal cord neurons and neuronal plasticity, in general, were identified from accumulated review of the neuroscience literature. Publications cited from chiropractic sources relevant to central neuronal plasticity and LTP/LTD were identified using the Index to Chiropractic Literature and informal review. STUDY SELECTION: Experimental studies examining LTP/LTD mechanisms in spinal neurons and more general references useful as an introduction to central neuronal plasticity and LTP/LTD are included.Data Extraction Experimental evidence presented in this review has been previously published and illustrates neuronal plasticity from an animal model for low back pain. DATA SYNTHESIS: Both in vitro and in vivo evidence identifying LTP and LTD in dorsal horn nociceptive neurons is reviewed. Of special interest are studies showing LTP in response to intense noxious stimulation and reports that Adelta-mechanosensitive afferent activation can reverse an existing LTP condition in dorsal horn neurons. CONCLUSIONS: The potential involvement of LTP in low back pain is discussed and a role for LTD in spinal manipulative therapy is proposed. The need for future studies is identified in the areas of spatial and temporal changes in symptomatology post-SMT of the low back; combining, sequencing, and comparing several therapeutic approaches; and demonstrating LTD in spinal cord neurons post-SMT-like stimulation.

An effect of ascorbic acid on delayed-onset muscle soreness.

Delayed-onset muscle soreness following strenuous use of the posterior calf muscles was studied to determine if ascorbic acid might have an effect on the appearance of this familiar pain. A double-blind, randomized, crossover study compared the soreness in subjects taking ascorbic acid against those taking a lactose placebo. Visual analog scales were used in conjunction with a variety of pain-challenging methods, and the results indicated a significant difference between experimental and placebo groups at the height of soreness. Typical soreness abatement scores of 25-44% were observed. A sample size of 19, lack of an untreated control group as well as the singular nature of the exercise and its intensity were considered limitations of the study.