Influence of dihydropyridines on the recovery of sensory function after a caudal nerve crush in the rat

Abstract

Nimodipine, a Ca²⁺ antagonist of the dihydropyridine type, is known to display a variety of neuropharmacological effects including facilitation of functional recovery following a crush of the sciatic nerve in the rat. In the present study, we investigated the effect of nimodipine, nifedipine (another Ca²⁺ antagonist with a lesser penetration in neural parenchyma) and Bay K 8644 (a Ca²⁺ agonist) treatment following a crush of the major caudal nerve. The caudal nerve crush model was used because this model provided the opportunity for longitudinal evaluation of nerve repair. Recovery of sensory function was tested by vocal reaction following local stimulation with a small electric current. The results suggest that nimodipine (20 mg/kg) both enhances the initial sprouting response and exerts an effect on the outgrowth rate of newly developed sprouts. Neither nifedipine (20 mg/kg) nor Bay K 8644 (0.5 mg/kg) had any influence on the recovery of nerve function. Furthermore, it was demonstrated that nimodipine, nifedipine and Bay K 8644 had no influence on nerve conduction velocity of the non-injured sciatic nerve indicating that there was no general beneficial effect of these agents on the peripheral nerve.