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Purinergic receptors of the nucleus of the solitary tract are involved in the ventilatory response to hypoxia
Author(s) -
De Paula Patricia Maria,
Marques Naira,
Menani José Vanderlei
Publication year - 2011
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.25.1_supplement.1076.8
Subject(s) - purinergic receptor , hyperventilation , ppads , cardiorespiratory fitness , endocrinology , suramin , chemistry , medicine , mean arterial pressure , receptor , heart rate , anesthesia , blood pressure
Hypoxia (HYP) triggers many cardiorespiratory responses, including increased pulmonary ventilation (VE), which depends on brainstem areas including the nucleus of the solitary tract (NTS). Studies have demonstrated the involvement of purinergic receptors of the surface of the medulla in the cardiorespiratory responses induced by HYP. Thus, we investigated the involvement of purinergic receptors of the NTS on cardiorespiratory responses induced by HYP in awake rats. Male Holtzman rats (280–320 g, n = 6) with stainless steel guide‐cannulas implanted in the NTS were used. We recorded mean arterial pressure (MAP), heart rate (HR) and VE before and after bilateral injections of saline (SAL) or suramin (SUR, a non‐selective purinergic receptor antagonist) into the NTS in normoxia (NORM, 21% O2) or HYP (7% O2). HYP reduced MAP (100 ± 11 mmHg, vs. NORM 121 ± 3 mmHg, p <0.05) and increased VE (1521 ± 376 ml/min/kg, vs. NORM 730 ± 227 ml/min/kg, p<0.05) without changing HR (388 bpm ± 32, vs. NORM 384 ± 6 bpm). Bilateral injections of SUR (2 nmol/100 nl) into the NTS reduced HYP‐induced hyperventilation (505 ± 208 ml/min/kg, vs. SAL 1508 ± 376 ml/min/kg, p<0.05) without changing MAP (Δ −5 ± 2 mmHg, vs. SAL −7 ± 10 mmHg) and HR (Δ 18 ± 24 bpm, vs. SAL 9 ± 12 bpm). Bilateral injections of SUR into the NTS did not change MAP, HR and VE in NORM. The results suggest that activation of purinergic receptors in the NTS facilitate HYP‐induced hyperventilation.