Unilateral whisker pad injection of botulinum toxin type a enhances spatial learning in mice

    loading  Checking for direct PDF access through Ovid

Abstract

The central cholinergic nervous system plays an important role in cognition, with acetylcholine hypofunction considered to be a major factor of dementia. Botulinum toxin type A (BoNT/A), a potent poison secreted by Clostridium botulinum, is used widely for dystonia treatment and facial cosmesis. BoNT/A injection inhibits acetylcholine release in the neuromuscular junction through cleavage of synaptosomal-associated protein of 25 kDa in cholinergic terminals. Furthermore, beyond the injection site, BoNT/A undergoes retrograde transport and transcytosis to the central nervous system from peripheral cholinergic terminals. However, whether peripheral BoNT/A injection affects the function of the central nervous system and induces learning deficits remains unclear. We injected mice with different doses of BoNT/A (2, 10, and 50 U/kg) or sterile saline (control) into the left whisker pad to test spatial learning performance at different times after injection using the Morris water maze. At 3 days and 4 weeks after injection, the spatial learning ability of the control and BoNT/A-treated mice showed no significant differences. Surprisingly, however, rather than spatial learning impairment at 6 weeks after injection, BoNT/A-treated mice spent less time than control mice in locating the experimental platform, indicating that BoNT/A facial injection might promote spatial learning. Furthermore, our study suggests that facial application of BoNT/A is safe and could play a positive role in ameliorating the spatial learning deficits associated with neurodegenerative diseases.

Related Topics

    loading  Loading Related Articles