Differential sensitivity of brainstem vs cortical astrocytes to changes in pH reveals functional regional specialization of astroglia

V Kasimov, O Larina, C Castaldo, N Marina, M Patrushev, Sergey Kasparov, A Gourine

Research output: Contribution to journalArticle (Academic Journal)

69 Citations (Scopus)
291 Downloads (Pure)

Abstract

Astrocytes might function as brain interoceptors capable of detecting different (chemo)sensory modalities and transmitting sensory information to the relevant neural networks controlling vital functions. For example, astrocytes that reside near the ventral surface of the brainstem (central respiratory chemosensitive area) respond to physiological decreases in pH with vigorous elevations in intracellular Ca2 and release of ATP. ATP transmits astroglial excitation to the brainstem respiratory network and contributes to adaptive changes in lung ventilation. Here we show that in terms of pH-sensitivity, ventral brainstem astrocytes are clearly distinct from astrocytes residing in the cerebral cortex. We monitored vesicular fusion in cultured rat brainstem astrocytes using total internal reflection fluorescence microscopy and found that 35% of them
respond to acidification with an increased rate of exocytosis of ATP-containing vesicular compartments. These fusion events require intracellular Ca2
signaling and are independent of autocrine ATP actions. In contrast,the rate of vesicular fusion in cultured cortical astrocytes is not affected by changes in pH. Compared to cortical astrocytes, ventral brainstem astrocytes display higher levels of expression of genes encoding proteins associated with ATP vesicular transport and fusion, including vesicle-associated membrane protein-3 and vesicular nucleotide transporter. These results suggest that astrocytes residing in different parts of the rat brain are functionally specialized. In contrast to cortical astrocytes, astrocytes of the brainstem chemosensitive area(s) possess signaling properties that are functionally relevant—they are able to sense
changes in pH and respond to acidification with enhanced vesicular release of ATP.
Original languageEnglish
Pages (from-to)435-441
Number of pages7
JournalJournal of Neuroscience
Volume33
Issue number2
DOIs
Publication statusPublished - 9 Jan 2013

Keywords

  • astrocytes
  • vesicle
  • ATP
  • glutamate

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