Looking to the stars for answers: Strategies for determining how astrocytes influence neuronal activity

Brainstem astrocytes control homeostatic regulation of caloric intake

“…The current study used chemogenetic approaches, both in vivo and in vitro , to study the effects of DMV astrocyte inhibition, an approach that is not without controversy (Shen et al., 2021), given chemogenetic inhibition may have bidirectional effects on astrocytes, with previous studies showing either an increase (Durkee et al., 2019), an attenuation (Kim et al., 2021), or no change (Van Den Herrewegen et al., 2021) in astrocyte calcium transients. There is notable diversity in the type and time course of calcium responses of astrocytes that are mediated via distinct mechanisms, however, (Khakh & Sofroniew, 2015; Paniccia et al., 2022) and astrocyte activity and gliotransmission may be modulated by additional mechanisms, including alterations in gap junctions, transporters and ion channels (Mazaud et al., 2021; Shen et al., 2021).…”

Role of Neuroglia in the Habenular Connection Hub of the Dorsal Diencephalic Conduction System

“…In addition, this fine structure is very dynamic [54]. Much has now been published on how astrocytes can influence glutamatergic neurotransmission (for reviews see [55,[57][58][59][60]). Incidentally, most research does not refer to tripartite synapses in the lateral habenula [59], but it is likely that the processes are also at play there; the DDCS is rich in glutamatergic fibers [23].…”

Astrocyte Heterogeneity in Regulation of Synaptic Activity

“…The existence of spatially patterned, transcriptionally unique astroglial types in the adult brain (as in [5][6][7][8][9][10]) suggests that astrocyte heterogeneity may derive, at least in part, from unique cell lineages that determine their molecular and functional profiles in adulthood [11]. Alternatively, many have argued that astrocyte heterogeneity, and even transcriptional profiles of astroglial types, derives from the neurovascular landscape where they find themselves positioned in the brain [4,[12][13][14][15].…”

“…However, whether different astroglia exhibit different patterns of calcium activity, or have different capacities to signal using calcium has not been clarified. For a more thorough discussion of function and heterogeneity of astroglial Ca 2+ signals, see [8,13,153].…”

“…For example, between brain regions, astrocytes have been shown to exhibit different patterns of calcium flux as well as different degrees of synaptic adjacency [6]. These observations are not only suggestive of different degrees and/or mechanisms of synapse regulation by astrocytes between brain regions, but have led to genesis of new tools and strategies for targeting and manipulating unique astroglial populations [7][8][9]. Together, these approaches provide us with the ability to examine in more detail how pathogenesis in various disease states alters function of specific astroglial populations.…”