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Role of purinergic neurotransmission in different brainstem CO2‐chemoreceptor regions
Author(s) -
Wenker Ian Christopher,
Sobrinho Cleyton R,
Takakura Anna C,
Moreira Thiago S,
Mulkey Daniel K
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.1137.13
Subject(s) - purinergic receptor , ppads , chemoreceptor , raphe , raphe nuclei , central chemoreceptors , neuroscience , purinergic signalling , brainstem , solitary tract , biology , premovement neuronal activity , serotonergic , chemistry , medicine , endocrinology , adenosine , receptor , serotonin , agonist , adenosine receptor
Central chemoreception is the mechanism by which specific brainstem regions, such as the solitary tract (NTS), medullary rapheand retrotrapezoid nucleus (RTN), regulate breathing in response to changes in tissue CO 2 /pH. In the RTN, the mechanism of chemoreception involves modulation of chemosensitive neurons by CO 2 ‐evoked astrocytic ATP release. However, it is not clear whether purinergic signaling influences CO 2 ‐responsiveness of other putative chemoreceptors. This study aimed to determine whether neuronal activity and CO 2 ‐responsivness of NTS and raphe chemoreceptors are influenced by purinergic signaling in vitro and in vivo . In brain slices, cell‐attached recordings show that CO 2 ‐sensitive neurons in the NTS, but not the raphe, respond to focal ATP application with ~3 fold increase in firing rate. However, bath application of a non‐specific P2‐receptor blocker (PPADS) had no effect on baseline activity or CO 2 ‐responsivness of NTS nor raphe neurons. In anaesthetized adult rats, injection of PPADS into either the caudal NTS or medullary raphe had no effect on baseline phrenic nerve activity or the ventilatory response to CO 2 . Further, immunohistochemical analysis of an astrocyte marker indicates that the RTN has a higher density of astrocytes compared to the NTS or medullary raphe. Together, these results suggest that purinergic signaling is a unique feature of RTN chemoreception.