Profiling of Differentiation Pattern of Neuro 2A (N2a) Cells upon Exposure to Dopamine, Corticosterone and Monosodium Glutamate
Authors: Mathew Smita , Keerikkattil Joy 
Published: May 2023

Our previous studies on the lineage tracking and differentiation of N2a cells reported the differential effects elicited upon exposure to dopamine (DA), corticosterone (CORT) and monosodium glutamate (MSG). The present study tested the hypothesis that DA induces catecholaminergic pathway of differentiation, CORT stimulates glial type differentiation and MSG stimulates glutamate-GABA differentiation. Mouse neural crest-derived cell line (Neuro2A cells, N2a cells) was treated with 10μM each of DA, CORT or MSG for 24, 48, 72 and 96 hrs with respective control groups. Immunocytochemical analysis with tyrosine hydroxylase (TH), dopamine β - hydroxylase (DBH), glial fibrillary acidic protein (GFAP) antibodies was tested. Quantitative analysis of the cells treated for 48 hrs showed significant TH fluorescence in Group I (medium containing ascorbic acid (AA) and phosphate buffered saline (PBS), Group II (DA), Group III (ethanol and PBS), Group IV (CORT), Group V (PBS) and Group VI (MSG) when compared with the untreated control group (medium only). A significant increase in the TH intensity was observed in Group VI compared to Groups I, II, III, IV and V. This suggests that MSG activates the dopaminergic neuron pathway. Enhanced significant DBH fluorescence observed in Group IV and V verses Group I and untreated control as well as Group II, III, IV and V compared to Group I. CORT group showed significant enhanced DBH expression verses MSG group. Though TH showed an enhanced expression in the MSG group compared to its respective control, DBH showed significant downregulation suggesting MSG inhibits the norepinephrine pathway. DA stimulates the DBH expression significantly compared to its respective control (Group I); suggesting DA stimulates the differentiation into noradrenergic and adrenergic cells. Analysis of N2a cells treated for 96 hrs showed intense GFAP expression in the Groups III and VI verses untreated control. The DA group showed significant reduction in the GFAP expression compared to the untreated control as well as Group I. CORT group also showed significant drop compared to its respective control group. CORT and DA seem not to activate the astrocytic lineage whereas MSG seems to activate the GFAP expression suggesting induction of astrocytic lineage. Apoptotic marker Caspase-3 showed significant fluorescence intensity in Group I and V1 compared to the untreated control. Significant upregulation observed in MSG compared to CORT as well. Our results suggest that MSG (glutamate) can induce differential regulation, both facilitatory and inhibitory control over DA release and can be both phasic and tonic in character. The inference is that glutamate plays a significant role in the differentiation pattern for dopaminergic and noradrenergic or adrenergic pathways. Furthermore astrocytic lineage is activated upon glutamate exposure. The stress hormone and the happy hormone can activate the noradrenergic or adrenergic pathways of differentiation. CUSAT Postdoctoral Fellowship - Dr. Smita Mathew. U.O.No.Ac.B3/PDF/2016-17(b) dt. 10.5.2017 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.