Spinal sufentanil in rats: part I: epidural versus intrathecal sufentanil and morphine

Abstract

Male Wistar rats were injected epidurally or intrathecally with increasing doses of sufentanil or morphine in order to determine differences in potency, onset and duration of analgesia and supra-spinal side-effects. For sufentanil, only small differences in the lowest ED50-values for analgesia and supra-spinal side-effects were observed between the two spinal routes. Given intrathecally, sufentanil had a somewhat faster onset but a shorter duration of action than did epidural sufentanil. However, intrathecal morphine when compared to epidural morphine had a faster onset with a greater potency and a longer duration of action. The stronger opioid activity of intrathecal morphine was also reflected in a reduced safety ratio for the blockade of the cornea reflex. These differences between the two opioids, with regard to their optimal route of spinal administration, are discussed in terms of lipophilicity and optimal clinical use.

Vocalization Responses After Spinal Administration of Bicuculline or Strychnine in Rats

“…An intrathecal cannula was placed at the level of the vertebra L 2 via the lumbar route under pentobarbital (6.0 mg/kg, intraperitoneally), Thalamonal (1.0 ml subcutaneously, corresponding fentanyl ∼200 μg/kg and droperidol ∼10 mg/kg) anesthesia, as described earlier (15). The animals were allowed to recover for 5–7 days between the cannulation and the vocalization experiments.…”

Probing opioid receptor–ligand interactions by employment of indolizidin‐9‐one amino acid as a constrained Gly2‐Gly3 surrogate in a leucine‐enkephalin mimic

“…All measurements were made in duplicate and repeated in three independent experiments. Measurement of spinal analgesia in rats was performed in animals equipped 4 days prior to testing with an intrathecal catheter at the lumbar level (39). Animals ( n = 3) were injected with either vehicle or compound 12 at doses of 5, 10 and 40 µg/rat.…”

Increased cold allodynia following intrathecal N-methyl-D-aspartate in rats with a mononeuropathy

“…During the same operation an intrathecal cannula was placed at the level L4/L5 via the lumbar route as described earlier by Boersma et al (1992). The dorsal aspect of the L3-L6 vertebrae was exposed by skin incision and a small cut through the paravertebral muscles.…”