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Effect of chronic hypoxia on agonist-induced tone and calcium signaling in rat pulmonary artery.
- Source :
-
American journal of physiology. Lung cellular and molecular physiology [Am J Physiol Lung Cell Mol Physiol] 2001 Jul; Vol. 281 (1), pp. L193-201. - Publication Year :
- 2001
-
Abstract
- The effect of chronic hypoxia (CH) for 14 days on Ca2+ signaling and contraction induced by agonists in the rat main pulmonary artery (MPA) was investigated. In MPA myocytes obtained from control (normoxic) rats, endothelin (ET)-1, angiotensin II (ANG II), and ATP induced oscillations in intracellular Ca2+ concentration ([Ca2+]i) in 85-90% of cells, whereas they disappeared in myocytes from chronically hypoxic rats together with a decrease in the percentage of responding cells. However, both the amount of mobilized Ca2+ and the sources of Ca2+ implicated in the agonist-induced response were not changed. Analysis of the transient caffeine-induced [Ca2+]i response revealed that recovery of the resting [Ca2+]i value was delayed in myocytes from chronically hypoxic rats. The maximal contraction induced by ET-1 or ANG II in MPA rings from chronically hypoxic rats was decreased by 30% compared with control values. Moreover, the D-600- and thapsigargin-resistant component of contraction was decreased by 40% in chronically hypoxic rats. These data indicate that CH alters pulmonary arterial reactivity as a consequence of an effect on both Ca2+ signaling and Ca2+ sensitivity of the contractile apparatus. A Ca2+ reuptake mechanism appears as a CH-sensitive phenomenon that may account for the main effect of CH on Ca2+ signaling.
- Subjects :
- Adenosine Triphosphate pharmacology
Angiotensin II pharmacology
Animals
Caffeine pharmacology
Calcium metabolism
Chronic Disease
Endothelin-1 pharmacology
Hypertension, Pulmonary complications
Hypertrophy, Right Ventricular etiology
Hypoxia complications
In Vitro Techniques
Indoles pharmacology
Intracellular Membranes metabolism
Male
Muscle, Smooth, Vascular metabolism
Muscle, Smooth, Vascular pathology
Pulmonary Artery drug effects
Pulmonary Artery pathology
Rats
Rats, Wistar
Reference Values
Vasoconstriction
Vasodilator Agents pharmacology
Calcium Signaling
Hypoxia physiopathology
Pulmonary Artery physiopathology
Vasomotor System physiopathology
Subjects
Details
- Language :
- English
- ISSN :
- 1040-0605
- Volume :
- 281
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- American journal of physiology. Lung cellular and molecular physiology
- Publication Type :
- Academic Journal
- Accession number :
- 11404262
- Full Text :
- https://doi.org/10.1152/ajplung.2001.281.1.L193