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Research Groups

Jonas Broman, Ph.D.

Jonas Broman

Jonas Broman, Ph.D.

Research Focus

Signals about painful stimuli are transmitted in synapses between peripheral nociceptors and neurons in the superficial dorsal horn. A strengthening of these synapses is believed to be an important contributing factor in many pain states. An increased efficacy of pain synapses can be observed following intense noxious stimulation, and is probably achieved through a mechanism similar to LTP in certain hippocampal synapses. However, the molecular mechanisms and synaptic modifications behind the increased synaptic strength are yet poorly understood. This project aims at elucidating the molecular modifications that occur in pain synapses following intense noxious stimulation.

We use a model where anesthetized rats are given an injection of the irritant capsaicin in one of the hind paws. At specified times after the injection, the spinal cords of the rats are removed and processed for electron microscopy. The presence and amount of different molecules of interest in the pain synapses are examined using immunogold labeling. To detect changes in the amount of molecules in different synapse types, labeling data from the capsaicin-stimulated side of the spinal cord is compared with data from the non-stimulated side.

Changes in the efficacy of pain synapses is presumably involved in the mechanism behind states of longstanding and severe pain. Knowledge of the molecular mechanisms behind such changes could point to ways to interfere with the development of chronic pain disorders.

Selected Publications

Larsson M, Broman J

Pathway-specific bidirectional regulation of CaMKII at spinal nociceptive synapses following acute noxious stimulation.

Journal of Neuroscience 26: 4198-4205, 2006

Larsson M, Broman J

Different basal levels of CaMKII phosphorylated at Thr286/287 at nociceptive and low threshold primary afferent synapses.

European Journal of Neuroscience 21: 2445-2458, 2005

Persson S, Broman J

Glutamate, but not aspartate, is enriched in trigeminothalamic tract terminals and associated with their synaptic vesicles in the rat nucleus submedius.

Experimental Brain Research 157: 152-161, 2004

Larsson M, Persson S, Ottersen OP, Broman J

Quantitative analysis of immunogold labeling indicates low levels and non-vesicular localization of L-aspartate in rat primary afferent terminals.

Journal of Comparative Neurology 430: 147-159, 2001

Broman J, Anderson S, Ottersen OP

Enrichment of glutamate-like immunoreactivity in primary afferent terminals throughout the spinal cord dorsal horn.

European Journal of Neuroscience 5: 1050-1061, 1993

Professor Jonas Broman

08-524 866 48
Department of Neuroscience
Karolinska Institutet
Retzius väg 8
S-17177 Stockholm, Sweden