Nitrendipine and motor activity of spinal cord injured rabbits

Background and purpose: Spinal cord injuries are often followed by profound motor and sensory deficit. They are a great medical and social problem because there is no effective drug therapy. It is well known that disturbances in Ca2+ accumulation into the nerve cells might contribute to nerve cells damage. So the purpose of the study was to investigate the influence of calcium channel blocker nitrendipine on motor activity of spinal cord injured rabbits. Material and methods: The study was carried out on adult rabbits of 2.5 - 3.5 kg body weight. Medial dorsal lumbal laminectomy was performed under pentobarbital anaesthesia. Experimental, lumbal spinal cord injury provoked by a strike of 50 p.cm caused a spontaneously reversible paraplegia ; while by 150 p.cm caused a spontaneously irreversible paraplegia. Hind limbs motor activity was controlled daily in accordance with Tarlov's system during the whole course of the experiment. Nitrendipine was injected intravenously immediately after the trauma and during the eight subsequent days in various doses. Results: Tested drug diminished motor deficit in the animals with spontaneously irreversible paraplegia. Doses of 0.3 ; 1.0 mg/kg dally and 2x0.5 mg/kg daily significantly improved motor deficit during all nine posttraumatic days. Conclusion: Spinal cord injury in rabbits, provoked by a strike of 150 p.cm resulted in a spontaneously irreversible paraplegia. Nitrendipine in dose related manner diminished motor deficit. The results support the opinion that calcium channel blockers can be used in the treatment of spinal cord injured persons