Neurologia medico-chirurgica
-
Neurol. Med. Chir. (Tokyo) · Jan 1997
Effects of intrathecal nonnarcotic analgesics on chronic tactile allodynia in rats: alpha 2-agonists versus somatostatin analog.
The effects of the intrathecal alpha 2-agonists tizanidine and clonidine and the somatostatin analog octreotide on an experimental rat model of tactile allodynia were investigated to determine the therapeutic potential for treating chronic neuropathic pain. Allodynia was induced by ligating the rat sciatic nerve. The mechanical threshold for paw withdrawal was assessed by applying von Frey hairs to quantify analgesic actions. ⋯ No side effect was observed at a 10-micrograms dose, at which the threshold was 88-96% of MPE. Intrathecal octreotide modestly increased the threshold to only 49-67% of MPE, showing a lesser analgesic effect, although no side effect was observed at a 4-micrograms dose. The antiallodynic effects of intrathecal tizanidine and clonidine were more potent than that of octreotide.