Christian S. Stohler, DMD, DrMedDent

The absence of consistent end organ abnormalities in many chronic pain syndromes triggered Dr. Stohler to the search for mechanisms that explain their clinical presentations. Contributions focus on the dissection of their complex and individually variable symptom expression, notably those involving head, neck and back muscles using model systems, delivering experientially-matched, sustained deep muscle pain. The work established the effect of deep pain on touch sensation, agonistic and antagonistic muscle function, and shed novel light on the degree to which the CNS shapes clinical severity. 

Using functional molecular imaging, he and his colleagues showed that the level of activation of mu-opioid neurotransmission in sustained pain contributes significantly to individual pain sensation and affect. Subsequently, his group demonstrated that both opioidergic and dopaminergic neurotransmission and genetic variants influencing their function further modulate clinical pain and emotional states, contributing to the increasing body of knowledge of genetic variants modulating clinically observable phenomena. The group was the first group to show placebo-induced activation of opioid neurotransmission in brain regions, including the rostral anterior cingulate, orbitofrontal and dorsolateral prefrontal cortex, anterior and posterior insula, nucleus accumbens, amygdala and others with some of these regions overlapping with those involved in pain, affective regulation and motivated behavior. With heightened pain-stress sensitivity being thought to confer risk for a host of health conditions, the team reported that a putatively functional genetic variant is associated with greater striatal dopamine release during pain. Overall, the scientific contributions show that inter-individual differences affect the CNS response to environmental challenges and thereby contribute to a person’s resilience or vulnerability to stressors, such as pain.