The effects of experimental tooth separation on memory function and brain neurotransmitters in mice

Abstract

In the present study, the effects of experimental separation of the lower incisor on memory function and the levels of brain neurotransmitters and related compounds were examined in mice at day 2, 7 and 14 after separation (0.5 or 1.0mm) treatment. The effects of the treatment on memory functions were tested by the multiple maze, T-maze and radial maze methods. The effects of the treatment on levels of neurotransmitter-related compounds in the hippocampus, cerebral cortex, striatum and hypothalamus were examined by high-performance liquid chromatography with an electrochemical detection system after the end of the each memory test. In mice, the experimental incisor separation induced dysfunction of all memory tested and increased the levels of 3-methoxy-1-hydroxyphenylglycol (MHPG), the main metabolite of the neurotransmitter noradrenaline, in all brain areas only on day 2 after treatment. These results suggest that incisor separation may inhibit the memory function of mice via activation of the central noradrenergic system.