Table 1.

Summary of the Toxoplasma gondii effects on main neurotransmitter systems.

Neurotransmitter	Toxoplasma Effects	Study Type	References
Glutamate	Cross-reactivity with NMDA-2D receptors.	In silico (UniProt database and Peptide Match program)	[74]
	AD signs associated with loss of NMDAR expression and neuronal death.	In vivo and in vitro (C57BL/6 mice).	[15]
	Downregulation of synaptosomal EAAT2, AMPA receptor subunit GluA1, and the NMDA receptor subunit GluN1	In vitro (Naval Medical Research Institute—NMRI-mice)	[26]
	Development of anti-NMDA encephalitis.	Case report	[75]
	Reduction in the astrocytic glutamate transporter, GLT-1 and increase in extracellular levels of glutamate. Abnormal EEG recordings.	In vivo and in vitro (C57BL/6 and BALB/c mice)	[76]
	Elevation of GLUN2 autoantibodies and reduction in Glun2A expression (NMDAR subunits). Reduction in the vesicular glutamate 1 transporter (VGLUT1) and post-synaptic density 95 (PSD-95).	In vitro (BALB/c mice)	[77]
GABA	Dendritic cells hypermigration through GABAergic signaling which allows parasitic systemic dissemination.	In vivo and in vitro (C57BL/6 mice bone marrow-derived DC and human monocyte-derived DC)	[36]
	Increased microglial cells hypermigration via GABAergic transmission.	In vitro (C57BL/6 mice astrocyte and microglia cell cultures)	[78]
	Activation of GABA-A receptors and L-type voltage-dependent calcium channels to modulate microglial activation and migration.	In vivo, ex vivo and in vitro (cell line NE-4C, mouse bone marrow-derived DCs and C57BL/6 mice)	[79]
	Diminished expression and altered cortical GAD67 distribution. Reduction in GABAergic transmission.	In vivo and in vitro (BALB/c and C57BL/6 mice)	[77,80]
Dopamine	Reduction in DRD1, DRD2, DRD4, and GRK6 gene expression, reducing receptor availability and increasing dopamine concentration.	In vitro (BALB/c mice)	[50]
	Decreased expression of Dopamine Transporter (DAT) and Vesicular Monoamine Transporter 2. Increasing locomotor activity to dopamine psychostimulants.	In vivo and in vitro (BALB/c mice)	[81]
	Increased dopamine synthesis and release. Increased DOPA decarboxylase (DDC) levels.	In vivo and in vitro (rat pheochromocytoma PC12 cells and Swiss Webster mouse)	[82,83]
	Decrease in D1-like receptors (DRD1, DRD5), MAO-A, and DARPP-32 gene expression, via MiR-132 RNA transcription.	In vitro (human neuroepithelioma cell line and CD-1 mice)	[84]
	Disruptions of dopamine-related pathways with DARPP-32 feedback and APP production.	In vitro (human WERI-Rb-1 eye cell line culture). Genome-wide analysis	[66]