In some literature articles, the term mechanism of action and mode of action (MoA) are used interchangeably; typically referring to the way in which the drug interacts and produces a medical effect. However, in actuality, a mode of action describes functional or anatomical changes, at the cellular level, resulting from the exposure of a living organism to a substance.  This differs from a mechanism of action, as it is a more specific term that focuses on the interaction between the drug itself and an enzyme or receptor and its particular form of interaction, whether through inhibition , activation , agonism , or antagonism . Furthermore, the term mechanism of action is the main term that is primarily used in pharmacology, whereas mode of action will more often appear in the field of microbiology or certain aspects of biology.
A microdialysis study in rats concluded that modafinil inhibits striatal and pallidal GABA release 14 . Moreover, modafinil dose-dependently increases extracellular glutamate and enhances excitatory glutamatergic neurotransmission in the ventromedial (VMT), ventrolateral (VLT), thalamus and hippocampal regions of wild-type rats 15 . Hence, modafinil’s tendency to increase the glutamate/GABA ratio may account for some of its wake-promoting effects, although dopamine agonists and dopamine itself both elicit glutamate release in the hippocampus 16 , raising the possibility that increases in extracellular glutamate may arise secondarily from modafinil’s action on DA.