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Activation of NTS A 1 adenosine receptors impairs cardiopulmonary chemoreflex responses of adrenal (ASNA), lumbar (LSNA) and renal (RSNA) sympathetic nerve activity
Author(s) -
Ichinose Tomoko K,
O'Leary Donal S,
Scislo Tadeusz J
Publication year - 2009
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.23.1_supplement.610.12
Subject(s) - adenosine , endocrinology , chemistry , adenosine receptor , agonist , stimulation , medicine , adenosine a2a receptor , receptor
Activation of NTS A 1 adenosine receptors evokes differential sympathoactivation (ASNA>RSNA≥LSNA). These responses were attenuated/abolished by sinoaortic denervation plus vagotomy or blockade of glutamatergic transmission in the NTS suggesting that these receptors may inhibit baroreflex transmission in the NTS (Am J Physiol 283: H1588‐99, 2002; 294: H172‐82, 2008). However, potential inhibition of cardiopulmonary chemoreceptors may also contribute to the A 1 adenosine‐receptor‐mediated differential regional sympathoactivation. Therefore, in the present study we compared regional sympathoinhibition evoked by right atrial injections of 5HT3 receptor agonist (phenylbiguanide (PBG) 1‐8 μg/kg) before and after stimulation of NTS A 1 adenosine receptors (microinjections of CPA, 330 pmol/50 nl) in urethane/chloralose anesthetized rats (n=7). Activation of cardiopulmonary chemoreceptors evoked differential, dose dependent sympathoinhibition (RSNA>ASNA>LSNA). The responses to all doses of PBG (Δ%) were greatly attenuated following stimulation of NTS A 1 adenosine receptors (‐95.6±1.2 vs. ‐40.4±8.5, ‐75.4±5.8 vs. ‐27.5±6.8, ‐60.9±3.3 vs. ‐29.1±7.3, for RSNA, ASNA and LSNA respectively at the maximal dose of PBG). We conclude that activation of A 1 adenosine receptors in the NTS differentially inhibits the cardiopulmonary chemoreflex responses of regional sympathetic outputs. NIH HL‐67814