FIGURE 2.

Schematic of Ca²⁺ dependent and independent gliotransmitter release. Astrocytes can release gliotransmitters through a variety of mechanisms dependent and independent of calcium. Glutamate has been shown to be released via a variety of mechanisms. These mechanisms include exocytosis, lysosomes, hemichannels, exchangers, anion channels, antiporters as well as channels such as TREK-1 and Bestropin-1 (BEST-1) (Araque et al., 2000; Montana et al., 2004; Zhang et al., 2004; Xu et al., 2007; Malarkey and Parpura, 2008; Yang et al., 2019; Okada et al., 2021). GABA on the other hand, has been shown to be released via BEST-1, hemichannels, as well as anion channels and transporters (Kozlov et al., 2006; Jiménez-González et al., 2011; Le Meur et al., 2012; Yoon and Lee, 2014; Christensen et al., 2018; Kwak et al., 2020). ATP can be released via hemichannels, exocytosis, anion channels, and lysosomes (Bezzi and Volterra, 2001; Fujii et al., 2017; Xiong et al., 2018). Lastly, D-serine has been shown to be released via exocytosis, BEST-1, and hemichannels (Wolosker et al., 1999; Martineau et al., 2013; Sild and Van Horn, 2013; Herman, 2018; Koh et al., 2022; Linsambarth et al., 2022; Park et al., 2022; Tapanes et al., 2022). Created with BioRender.com.