Serotonergic Facilitation of Forelimb Functional Recovery in Rats with Cervical Spinal Cord Injury

AbstractSerotonergic agents can improve the recovery of motor ability after a spinal cord injury. Herein, we compare the effects of buspirone, a 5-HT1A receptor partial agonist, to fluoxetine, a selective serotonin reuptake inhibitor, on forelimb motor function recovery after a C4 bilateral dorsal funiculi crush in adult female rats. After injury, single pellet reaching performance and forelimb muscle activity decreased in all rats. From 1 to 6  weeks after injury, rats were tested on these tasks with and without buspirone (1–2 mg/kg) or fluoxetine (1–5 mg/kg). Reaching and grasping success rates of buspirone-treated rats improved rapidly within 2 weeks after injury and plateaued over the next 4 weeks of testing. Electromyography (EMG) from selected muscles in the dominant forelimb showed that buspirone-treated animals used new reaching strategies to achieve success after the injury. However, forelimb performance dramatically decreased within 2 weeks of buspirone withdrawal. In contrast, fluoxetine treatment resulted in a m ore progressive rate of improvement in forelimb performance over 8 weeks after injury. Neither buspirone nor fluoxetine significantly improved quadrupedal locomotion on the horizontal ladder test. The improved accuracy of reaching and grasping, patterns of muscle activity, and increased excitabilit y of spinal motor–evoked potentials after buspirone administration reflect extensive reorganization of connectivity within and between supraspinal ...
Source: Neurotherapeutics - Category: Neurology Source Type: research