+ Site Statistics
References:
54,258,434
Abstracts:
29,560,870
PMIDs:
28,072,757
+ Search Articles
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ PDF Full Text
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Translate
+ Recently Requested

Maturation of the response to bradykinin in resistance and conduit pulmonary arteries



Maturation of the response to bradykinin in resistance and conduit pulmonary arteries



Cardiovascular Research 44(2): 416-428



Immaturity of the endothelial-dependent relaxation is thought to be characteristic of the newborn pulmonary elastic arteries. In adulthood, the reactivity of different pulmonary arterial segments varies. Therefore, we investigated the presence of endothelial heterogeneity in perinatal porcine pulmonary arteries and compared it with the adult by studying the bradykinin-, substance P- and acetylcholine-induced relaxations in different arteries. Three types of pulmonary arteries (large conduit elastic, distal branching and resistance-sized; in situ diameters 0.7-1.7, 0.3-0.5 and 0.1-0.2 mm, respectively) were isolated from lungs of adult (nine months), young (60-84 h), newborn (4 min) and near-term foetal pigs. They were mounted for isometric force recording, contracted first with K+ = 125 mmol/l (reference contraction). Cumulative concentration-response curves to acetylcholine, substance P or bradykinin were obtained from prostaglandin F2 alpha (30 mumol/l) precontracted vessels. The effects of captopril and O2(95 or 8%) were also determined. Experiments were terminated by adding 100 mumol/l papaverine, obtaining maximal relaxation, which was used for normalising relaxations. (i) Acetylcholine: In resistance arteries, relaxations were absent in the newborn and the adult. In conduit arteries, they were present from 60-84 h onward. (ii) Substance P: In resistance arteries, relaxations were only present in the adult. In the other two types of arteries, rudimentary relaxations were present from the mature foetal stage onward. (iii) Bradykinin: In resistance arteries, identical relaxations were present at all ages which, in the foetus and the adult, were insensitive to changes in O2 levels (95 to 8%). In conduit arteries, concentration-dependent relaxations were present from birth, increasing in amplitude with age and these were potentiated by captopril. Foetal conduit arteries relaxed to the single application of 0.1 mumol/l bradykinin, indicating age-dependent tachyphylaxis. (i) Bradykinin is unique among endothelium-dependent vasodilators in being able to relax all vascular segments, at all ages, subject to tachyphylaxis and bradykinin-breakdown but independent of the prevailing O2 concentration. (ii) Heterogeneity of the relaxations between conduit and resistance arteries is evident from the mature foetal stage onward. (iii) The type of agonist, the type of vessel and the age each independently determine the presence or absence of endothelial relaxations. Therefore, the perinatal pulmonary circulation is not immature with respect to endothelial-dependent relaxation; rather, the nature of this process changes within the perinatal period and between birth and adulthood.

(PDF emailed within 1 workday: $29.90)

Accession: 046631797

Download citation: RISBibTeXText

PMID: 10690318


Related references

Perinatal development influences mechanisms of bradykinin-induced relaxations in pulmonary resistance and conduit arteries differently. Cardiovascular Research 51(1): 140-150, 2001

Effects of atrial natriuretic peptide and nitroprusside on isolated pulmonary resistance and conduit arteries from rats with pulmonary hypertension. British Journal Of Pharmacology. 110(4): 1363-1368, 1993

Vasodilative responses of coronary conduit and resistance arteries to bradykinin are preserved in patients with coronary spastic angina Comparison with acetylcholine. Circulation 98(17 SUPPL ): I404-I405, Oct 27, 1998

Differing voltage-gated K+ currents in rat conduit and resistance pulmonary arteries. Biophysical Journal 80(1 Part 2): 214a, January, 2001

Bradykinin relaxes newborn porcine pulmonary resistance arteries. Journal of Vascular Research 33(SUPPL 2): 15, 1996

Chronic hypoxia up-regulates nitric oxide synthase in rat conduit and resistance pulmonary arteries. Journal of Pathology 189(SUPPL ): 24A, 1999

Electrophysiologically distinct smooth muscle cell subtypes in rat conduit and resistance pulmonary arteries. Journal of Physiology (Cambridge) 538(3): 867-878, 1 February, 2002

Differential oxygen sensitivity of calcium channels in rabbit smooth muscle cells of conduit and resistance pulmonary arteries. Journal of Physiology 491: 511-518, 1996

Differential distribution of electrophysiologically distinct myocytes in conduit and resistance arteries determines their response to nitric oxide and hypoxia. Circulation Research 78(3): 431-442, 1996

Differences in nitric oxide production in porcine resistance arteries and epicardial conduit coronary arteries. Journal of Cellular Physiology 168(3): 539-548, 1996

Biphasic response to bradykinin in isolated porcine iliac arteries is mediated by bradykinin B1 and B2 receptors. Journal of Cardiovascular Pharmacology 31(2): 306-313, 1998

Acetylcholine and bradykinin enhance hypotension and affect the function of remodeled conduit arteries in SHR and SHR treated with nitric oxide donors. Brazilian Journal of Medical and Biological Research 38(6): 959-966, 2005

Beneficial effects of lifelong caloric restriction on endothelial function are greater in conduit arteries compared to cerebral resistance arteries. Age 36(2): 559-569, 2014

Exercise training enhances Bradykinin-mediated relaxation in porcine conduit arteries isolated from chronic coronary occluded hearts. FASEB Journal 11(3): A290, 1997

Development of the pulmonary arteries after the Norwood procedure: comparison between Blalock-Taussig shunt and right ventricular-pulmonary artery conduit. Annals of Thoracic Surgery 86(4): 1299-1304, 2008