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Differential role of peripheral chemoreceptors in the cardiovascular responses to obstructive apnea (OA) in normotensive and spontaneously hypertensive rats
Author(s) -
CRAVO SERGIO L,
ROSSI MARCIO V,
SILVA TIAGO A,
ANGHEBEN JULIANA M,
SCHOORLEMMER GUSS HM
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.1077.19
Subject(s) - chemoreceptor , medicine , microneurography , heart rate , peripheral , anesthesia , blood pressure , baroreceptor , balloon catheter , mean arterial pressure , endocrinology , baroreflex , cardiology , balloon , receptor
Recently we developed a new method to induce OA in unrestrained conscious rats. OA was induced by filling a balloon‐tipped catheter placed inside a rigid Teflon tube implanted in the trachea. Microinjections of 12–14 μL of water through the open end of the catheter occluded airways without inducing pain. Male Wistar or SHR rats (350–400 g) were anesthetized for implantation of tracheal balloon and arterial pressure (MAP) and heart rate (HR) recordings. After 5–10 days animals were submitted to 15 s episodes of OA. Peripheral chemoreceptors were inactivated by ligature of the carotid body artery. Results obtained demonstrated that in normotensive rats (115 ± 3 mmHg) OA produced pressor (26 ± 5 mmHg) and bradycardic responses (−253 ± 7 bpm). These responses were not affected by peripheral chemoreceptor inactivation (21 ± 3 mmHg and −244 ± 16 bpm, respectively). MAP and HR baseline values in SHR were 161 ± 6 mmHg and 379 ± 11 bpm. Pressor responses to OA in SHR were enhanced (64 ± 2 mmHg), whereas HR responses were similar (−215 ± 31 bpm) to normotensive animals. In SHR chemoreceptor inactivation reduced pressor and HR responses to OA (20 ± 4 mmHg and −84 ± 30 bpm, respectively). These results indicate that pressor responses to OA are enhanced in SHR, suggesting an increased vascular reactivity in these animals. Chemoreflexes exert a differential role in cardiovascular responses to OA in these strains.