Chat, short for choline acetyltransferase, is a synthesizing enzyme for acetylcholine (ACh) [1]. ACh is a neurotransmitter involved in many physiological functions, such as muscle movement, memory, and learning. Cholinergic neurons, which produce ACh, are identified by high concentrations of Chat, and the creation of transgenic mice like the ChAT-eGFP mouse has been advantageous for studying cholinergic neurons in the central and peripheral nervous systems [1].

In the ChAT-eGFP transgenic mouse study, while there was a complete overlap between the transgenic expression of eGFP and immunohistochemical staining in the cholinergic basal forebrain, differences were noted in other areas. For example, in the cortex and hippocampus, some small neurons were either only labeled with the antibody or only expressed eGFP. Also, no transgenic eGFP expression was found in certain tegmental nuclei cholinergic cells. This indicates that caution should be exercised when choosing this transgenic mouse line for research, as not all areas of Chat expression are accurately represented by eGFP expression [1].

In conclusion, Chat is crucial for the synthesis of acetylcholine, playing a key role in neural communication. The ChAT-eGFP transgenic mouse model has been valuable in mapping the distribution of cholinergic neurons, revealing both consistent and inconsistent areas of Chat expression visualization. These findings contribute to a better understanding of the role of cholinergic neurons in normal and potentially disease-related neural functions [1].

References:

1. Gamage, Rashmi, Zaborszky, Laszlo, Münch, Gerald, Gyengesi, Erika. 2023. Evaluation of eGFP expression in the ChAT-eGFP transgenic mouse brain. In BMC neuroscience, 24, 4. doi:10.1186/s12868-023-00773-9. https://pubmed.ncbi.nlm.nih.gov/36650430/