Albrecht Wild

B-vitamins potentiate the antinociceptive effect of diclofenac in carrageenin-induced hyperalgesia in the rat tail pressure test

B-vitamins possess antinociceptive and antiinflammatory activity. The rat tail pressure test was used to examine whether a mixture of the vitamins B1, B6, and B12, clinically used as Neurobion, has antinociceptive activity itself or potentiates the effect of the non-steroidal antiinflammatory drug (NSAID) diclofenac on carrageenin-induced hyperalgesia. Only the highest dose of the vitamin mixture (667 mg/kg B1 and B6, 6.7 mg/kg B12 p.o.) exhibited antinociceptive activity. Nevertheless, lower doses which alone were lacking in activity (100-250 mg/kg B1 and B6, 1-2.5 mg/kg B12 p.o.) dose-dependently potentiated the antinociceptive of diclofenac. This result supports the clinical experience of a reduced need for diclofenac when B-vitamins are administered concomitantly.

Do local vasomotor effects elicit the motor deficits induced by intrathecally applied substance P antagonists in the rat

The intrathecal application of the substance P (SP) antagonists [D-Pro2,D-Trp7,9]SP (DPDT) and [D-Arg1, D-Pro2, D-Trp7,9, Leu11]SP (DAPTL) to the lumbar region of intact, freely moving rats produced laming of the hindlimbs at doses of 0.375 nmol and above, and 1.5 nmol and above, respectively. In addition, the administration of DPDT (doses of 25 and 0.18 nmol) and DAPTL (25 and 0.6 nmol) produced a powerful constriction of the dorsal median spinal vein (DMSV) in decerebrated, unanaesthetised rats. Intrathecal SP (25 or 1.0 nmol) had a similar action on the spinal circulation to DPDT and DAPTL, though laming was first observed at doses of 30 nmol and higher. This suggests that intrathecally applied SP antagonists do not elicit laming by causing an obstruction of the venous drainage of the spinal cord. Disturbances of the spinal circulation could, however, influence the results of behavioural or physiological experiments in which SP or its analogues are administered intrathecally.