Central sensitization in medullary dorsal horn involves gap junctions and hemichannels.

Central sensitization is a fundamental mechanism contributing to acute and chronic pain conditions. Our previous studies have documented a glutamatergic, purinergic and glial-dependent central sensitization that can be induced in rat medullary dorsal horn nociceptive neurons by mustard oil application to the tooth pulp. This study showed that carbenoxolone, a potent gap junction and hemichannel blocker, completely blocked all parameters of mustard oil-induced central sensitization tested in functionally identified medullary dorsal horn nociceptive neurons. These results represent the first evidence suggesting that gap junctions and hemichannels may have a critical role in mediating central sensitization in dorsal horn nociceptive neurons and may account for the spread as well as development of central sensitization.