"Monoaminergic Neurotransmitters Promote the Percentage of Recovery of Swimming and Ambulation Behaviors following Central Nervous System Lesion in the Leech"

Abstract

After central nervous system (CNS) injury, the body loses its ability to move at different levels depending on the extension of the lesion. Monoaminergic neurotransmitters play a determining role in animal movement and neuronal regeneration, suggesting they may have a role in motor function recovery after central injury. This study aimed to determine the role of monoaminergic neurotransmitters in the recovery percentage of swimming and ambulation after CNS lesion. The study tested the role of monoaminergic neurotransmitter depletion with reserpine on the recovery percentage of swimming and ambulation behaviors following obturation of the CNS in the Mexican leech, Haementeria officinalis. After neurotransmitter depletion, in one group serotonin was replaced to evaluate its role. Every experimental assay included: control, reserpine, lesion, reserpine-lesion, and reserpine-lesionserotonin. In each group of 6 organisms, the recovery percentage of animals was determined. A total of seven assays were performed and reported as means±SE. After lesion, almost all of the injured animals lost swimming and ambulation behaviors. Seven days later, 68.42±11.11% (n=7) of the groups recovered their swimming ability, but with reserpine, only 4.71±4.71% (n=7, p=0.0002) and 94.28±5.71% recovered their ambulatory ability, but with reserpine, recuperated only 50.86±8.74% (n=7, p=0.0024). The exclusive injection of reserpine had no effect on these movement patterns. The acute administration of serotonin did not promote the recovery, 14.6±9% (n=5) and 55.8±10.95% (n=5) respectively. Monoaminergic neurotransmitters promoted the recovery percentage in swimming and ambulation abilities after CNS lesion. The restored serotonin did not contribute to the recovery percentage.