BACKGROUND: The research on conductive @entity1337 induced by perineural opioids generated a large body of conflicting data. In this study we reassessed the antinociceptive response to perineural administration of @entity1286 , @entity3575 or @entity6882 in a @entity35 model. METHODS: Analgesia was assessed using the hind paw withdrawal latency (HPWL) response to radiant heat. The opioid dose producing 20% of maximal possible effect (20%MPE) for systemic @entity1337 was calculated for each drug. Then sciatic blockade was performed with the dose corresponding to 20%MPE. The injected hind paw was used to measure direct perineural effect and the contralateral hind paw was used as an indicator of systemic effect. RESULTS: The response latency produced by @entity1286 or @entity3575 was not significantly different for ipsilateral (perineural effect) or contralateral (systemic effect) paw (27+/-11 vs. 28+/-16 and 3l+/-16 vs. 23+/-16 s, respectively). However, the @entity6882 group showed significantly higher %MPE for the ipsilateral paw (79+/-32 s) than for the contralateral paw (27+/-22 s). CONCLUSIONS: The results indicate that perineural @entity3575 or @entity1286 do not produce @entity1337 . @entity616 produced by @entity6882 was attributed to local anesthetic-like effect, rather than to drug interaction with opioid receptor.

Perineural antinociceptive effect of opioids in a XXXX model.

@entity1337 :: ('MESH:D000699', 'Disease') :: ['analgesia'] @entity6882 :: ('MESH:D008614', 'Chemical') :: ['meperidine'] @entity1286 :: ('MESH:D009020', 'Chemical') :: ['morphine'] @entity35 :: ('10116', 'Species') :: ['rat'] @entity3575 :: ('MESH:D005283', 'Chemical') :: ['fentanyl'] @entity616 :: ('MESH:D006327', 'Disease') :: ['Perineural block']
@entity35 :: (10116,Species) :: ['rat']
