BACKGROUND: Low doses of local anesthetics applied to the young @entity35 spinal cord in vitro have been shown to inhibit @entity7183 -evoked responses. The aim of this work was to investigate whether such low doses applied epidurally selectively reduce nociceptive responses in vivo and to investigate the influence of postnatal development on such local anesthetic actions. METHODS: Three groups of @entity35 pups aged 3, 10, and 21 days were studied. The threshold of the flexion withdrawal reflex to mechanical stimulation was determined in the hind limb at each age. @entity158 was induced in the right hind limb with 2% carrageenan, causing a reduction in the sensory threshold on that side. The difference in threshold between the two sides represents inflammatory @entity56 . The effect of low-dose epidural @entity1341 on sensory thresholds and thus the induced @entity56 was also determined for each age group. RESULTS: Inflammatory @entity56 was selectively attenuated by very low doses of @entity1341 (concentration range. 0.004-0.0625%), which did not affect the sensory threshold in the contralateral uninflamed limb. This effect was also age-related, with younger @entity35 being more sensitive than older @entity35 . CONCLUSIONS: The effects of epidural @entity1341 in the @entity1 @entity35 are developmentally regulated. Lower doses have a selective analgesic effect that decreases with increasing postnatal age.

@entity158 and XXXX are selectively reversed by epidural @entity1341 and are developmentally regulated.

@entity1 :: ('9606', 'Species') :: ['infant'] @entity7183 :: ('10185', 'Species') :: ['C-fiber'] @entity1341 :: ('MESH:D002045', 'Chemical') :: ['bupivacaine'] @entity56 :: ('MESH:D004342', 'Disease') :: ['hypersensitivity'] @entity158 :: ('MESH:D010146', 'Disease') :: ['Inflammatory pain'] @entity35 :: ('10116', 'Species') :: ['rat', 'rats']
@entity56 :: (MESH:D004342,Disease) :: ['hypersensitivity']
