Abstract
Aims: Atrial natriuretic peptide (ANP) is released from the heart in response to hypoxia and helps mitigate the development of pulmonary hypertension. However, the mechanism of hypoxia-induced ANP release is not clear. The cardiac atria are the primary source of ANP secretion under normal conditions, but right ventricular ANP expression is markedly up-regulated during adaptation to hypoxia. We sought to better understand mechanisms of cardiac ANP release during adaptation to hypoxia. Main methods: We measured hypoxia-induced ANP release from isolated perfused rat hearts obtained from normoxia and hypoxia-adapted rats before and after removal of the atria. Key findings: In both normoxia- and hypoxia-adapted hearts, ANP levels in the perfusate increased within 15 min of hypoxia. Hypoxia-induced ANP release was greater from hypoxia-adapted than normoxia-adapted hearts. Baseline and hypoxia-induced ANP release were considerably greater with the atria intact (213 ± 29 to 454 ± 62 and 281 ± 26 to 618 ± 87 pg/ml for normoxia- and hypoxia-adapted hearts respectively, P< 0.001 for both) than with atria removed (94 ± 17 to 131 ± 32 and 103 ± 26 to 201 ± 55 pg/ml, respectively, P< 0.002 for both). Hypoxia-induced ANP release was reduced over 80% by removing the atria in both normoxia- and in hypoxia-adapted hearts. Acute hypoxia caused a transient increase in lactate release and reductions in pH and left ventricular generated force, but no differences in pH or left ventricular generated force were seen between normoxia- and hypoxia-adapted rats. Significance: We conclude that the right ventricle is not a major source of cardiac ANP release in normoxia- or hypoxia-adapted rats.
Original language | English |
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Pages (from-to) | 382-389 |
Number of pages | 8 |
Journal | Life Sciences |
Volume | 87 |
Issue number | 11-12 |
DOIs | |
Publication status | Published - Sep 2010 |
Externally published | Yes |
Keywords
- Atrial natriuretic peptide (ANP)
- Cardiac atria
- Hypoxia
- Hypoxic pulmonary hypertension
- Isolated perfused heart