Protective effect of alpha7 nAChR: Behavioural and morphological features on neuropathy

Acute administration of PNU-282987, 10 and 30 mg kg−1 p.o. (15 days after ligation), was able to reduce hyperalgesia in a methyllicaconitine-reversed manner. This alpha7 nAChR agonist exerted no analgesic effects. Chronic PNU-282987 treatments, 30 mg kg−1 once a day for 7 days and 10 mg kg−1 for 28 days, were able to decrease pain perception. The histological studies highlighted that the ligation induces oedema and macrophagic infiltrate. Moreover, osmicated preparations revealed a decrease in axons' compactness and diameter, together with a significant loss of myelin sheath. Repeated treatment with PNU-282987 reduced the presence of oedema and macrophagic infiltrate and, on the coronal sections of the nerve, a significant higher myelin sheath, axonal diameter and number of fibers were observable. These results strongly suggest the pivotal role of alpha7 nAChR in the neuroprotection during neuropathy.