Calcitonin gene-related peptide modulates pulmonary vascular reactivity in isolated rat lungs

1994 ◽  
Vol 77 (1) ◽  
pp. 142-146 ◽  
Author(s):  
P. L. Janssen ◽  
A. Tucker
Keyword(s):  
Vascular Reactivity ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Acute Hypoxia ◽  
Calcitonin Gene Related Peptide ◽  
Ang Ii ◽  
Related Peptide ◽  
Pulmonary Vasoconstriction ◽  
Rat Lungs ◽  
Pressor Responses ◽  
Calcitonin Gene

The role of calcitonin gene-related peptide (CGRP) in modulating hypoxic pulmonary vasoconstriction was assessed. The effects of CGRP and its antagonist [CGRP-(8–37)] on responses to acute hypoxia (3% O2) and angiotensin II (ANG II; 0.4 microgram) were studied in isolated lungs of male Sprague-Dawley rats perfused with a salt solution. Rats with pulmonary hypertension, induced by simulated altitude exposure, were also used to determine the actions of CGRP in a remodeled pulmonary vascular bed. In normotensive (NT) and altitude-exposed (AE) lungs, CGRP injections (10 nM), given after stable pressor responses were attained, attenuated (P < 0.05) subsequent hypoxic pressor responses. Pretreatment with CGRP-(8–37) (10 nM) enhanced (P < or = 0.05) initial ANG II-induced pressor responses in both AE and NT lungs. CGRP-(8–37) pretreatment (10 nM) had little influence on the hypoxic pressor responses in either NT or AE lungs. Results indicate that CGRP modulates hypoxic pulmonary vasoconstriction and that CGRP-(8–37) enhances pressor responses to ANG II in NT and AE rat lungs.

Inhibition of hypoxic pulmonary vasoconstriction by antagonists of store-operated Ca2+ and nonselective cation channels

2005 ◽  
Vol 289 (1) ◽  
pp. L5-L13 ◽  
Author(s):  
Letitia Weigand ◽  
Joshua Foxson ◽  
Jian Wang ◽  
Larissa A. Shimoda ◽  
J. T. Sylvester
Keyword(s):  
Hypoxic Pulmonary Vasoconstriction ◽  
Acute Hypoxia ◽  
Pulmonary Arteries ◽  
Cation Channels ◽  
Pulmonary Vasoconstriction ◽  
Nonselective Cation Channels ◽  
Pressor Responses ◽  
Intracellular Ca ◽  
Pulmonary Arterial

Previous studies indicated that acute hypoxia increased intracellular Ca2+ concentration ([Ca2+]i), Ca2+ influx, and capacitative Ca2+ entry (CCE) through store-operated Ca2+ channels (SOCC) in smooth muscle cells from distal pulmonary arteries (PASMC), which are thought to be a major locus of hypoxic pulmonary vasoconstriction (HPV). Moreover, these effects were blocked by Ca2+-free conditions and antagonists of SOCC and nonselective cation channels (NSCC). To test the hypothesis that in vivo HPV requires CCE, we measured the effects of SOCC/NSCC antagonists (SKF-96365, NiCl2, and LaCl3) on pulmonary arterial pressor responses to 2% O2 and high-KCl concentrations in isolated rat lungs. At concentrations that blocked CCE and [Ca2+]i responses to hypoxia in PASMC, SKF-96365 and NiCl2 prevented and reversed HPV but did not alter pressor responses to KCl. At 10 μM, LaCl3 had similar effects, but higher concentrations (30 and 100 μM) caused vasoconstriction during normoxia and potentiated HPV, indicating actions other than SOCC blockade. Ca2+-free perfusate and the voltage-operated Ca2+ channel (VOCC) antagonist nifedipine were potent inhibitors of pressor responses to both hypoxia and KCl. We conclude that HPV required influx of Ca2+ through both SOCC and VOCC. This dual requirement and virtual abolition of HPV by either SOCC or VOCC antagonists suggests that neither channel provided enough Ca2+ on its own to trigger PASMC contraction and/or that during hypoxia, SOCC-dependent depolarization caused secondary activation of VOCC.

scholarly journals Evidence for a role of protein kinase C in hypoxic pulmonary vasoconstriction

1999 ◽  
Vol 276 (1) ◽  
pp. L90-L95 ◽  
Author(s):  
Norbert Weissmann ◽  
Robert Voswinckel ◽  
Thorsten Hardebusch ◽  
Simone Rosseau ◽  
Hossein Ardeschir Ghofrani ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Nadph Oxidase ◽  
Superoxide Anion ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Ang Ii ◽  
Pkc Inhibitor ◽  
Pulmonary Vasoconstriction ◽  
Pressor Responses ◽  
Hypoxic Vasoconstriction

Hypoxic pulmonary vasoconstriction (HPV) matches lung perfusion to ventilation, thus optimizing gas exchange. NADPH oxidase-related superoxide anion generation has been suggested as part of the signaling response to hypoxia. Because protein kinase (PK) C activation can occur during hypoxia and PKC activation is known to be critical for NADPH oxidase stimulation in different cell types, we probed the role of PKC in hypoxic vasoconstriction in intact rabbit lungs. Control vasoconstrictor responses were elicited by angiotensin II (ANG II) and the stable thromboxane analog U-46619. Portions of the experiments were performed while NO synthesis and prostanoid generation were blocked with N G-monomethyl-l-arginine and acetylsalicylic acid to avoid confounding effects due to interference with these vasoactive mediators. The PKC inhibitor H-7 (10–50 μM) caused dose-dependent inhibition of HPV, but this agent lacked specificity because ANG II- and U-46619-induced vasoconstrictions were correspondingly suppressed. In contrast, low concentrations of the specific PKC inhibitor bisindolylmaleimide I (BIM; 1–15 μM) strongly inhibited the hypoxic vasoconstriction without any interference with the responses to the pharmacological agents. Superimposable dose-inhibition curves were also obtained for BIM when lung NO synthesis and prostanoid generation were blocked throughout the experiments. Under either condition, BIM did not affect normoxic vascular tone. The PKC activator farnesylthiotriazole (FTT), ascertained to stimulate rabbit NADPH oxidase by provocation of alveolar macrophage superoxide anion generation in vitro, caused rapid-onset, transient pressor responses in normoxic lungs. After FTT, the hypoxic vasoconstrictor response was totally suppressed, in contrast to the largely maintained pressor responses to ANG II and U-46619. The lungs became refractory even to delayed hypoxic challenges after FTT application. In conclusion, these data support the concept that activation of PKC is involved in the transduction pathway forwarding pulmonary vasoconstriction in response to alveolar hypoxia.

Angiotensin II mediates postischemic leukocyte-endothelial interactions: role of calcitonin gene-related peptide

2007 ◽  
Vol 292 (6) ◽  
pp. H3032-H3037 ◽  
Author(s):  
Mozow Yusof ◽  
Kazuhiro Kamada ◽  
F. Spencer Gaskin ◽  
Ronald J. Korthuis
Keyword(s):  
Angiotensin Ii ◽  
Nadph Oxidase ◽  
Calcitonin Gene Related Peptide ◽  
Type I ◽  
Receptor Blockade ◽  
Ang Ii ◽  
Cgrp Receptor ◽  
Related Peptide ◽  
Enhanced Production ◽  
Calcitonin Gene

Vascular inflammation and enhanced production of angiotensin II (ANG II) are involved in the pathogenesis of hypertension and diabetes, disease states that predispose the afflicted individuals to ischemic disorders. In light of these observations, we postulated that ANG II may play a role in promoting leukocyte rolling (LR) and adhesion (LA) in postcapillary venules after exposure of the small intestine to ischemia-reperfusion (I/R). Using an intravital microscopic approach in C57BL/6J mice, we showed that ANG II type I (AT1) or type II (AT2) receptor antagonism (with valsartan or PD-123319, respectively), inhibition of angiotensin-converting enzyme (ACE) with captopril, or calcitonin gene-related peptide (CGRP) receptor blockade (CGRP8-37) prevented postischemic LR but did not influence I/R-induced LA. However, both postischemic LR and LA were largely abolished by concomitant AT1 and AT2 receptor blockade or chymase inhibition (with Y-40079). Additionally, exogenously administered ANG II increased LR and LA, effects that were attenuated by pretreatment with a CGRP receptor antagonist or an NADPH oxidase inhibitor (apocynin). Our work suggests that ANG II, formed by the enzymatic activity of ACE and chymase, plays an important role in inducing postischemic LR and LA, effects that involve the engagement of both AT1 and AT2 receptors and may be mediated by CGRP and NADPH oxidase.

Protein kinase C-ε-null mice have decreased hypoxic pulmonary vasoconstriction

2003 ◽  
Vol 284 (4) ◽  
pp. H1321-H1331 ◽  
Author(s):  
Cassana M. Littler ◽  
Kenneth G. Morris ◽  
Karen A. Fagan ◽  
Ivan F. McMurtry ◽  
Robert O. Messing ◽  
...  
Keyword(s):  
Vascular Reactivity ◽  
Core Protein ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Null Mouse ◽  
Ang Ii ◽  
Pulmonary Vasoconstriction ◽  
Channel Expression ◽  
Perfused Lung ◽  
Pkc Isozymes ◽  
Oxide Synthase

PKC contributes to regulation of pulmonary vascular reactivity in response to hypoxia. The role of individual PKC isozymes is less clear. We used a knockout (null, −/−) mouse to test the hypothesis that PKC-ε is important in acute hypoxic pulmonary vasoconstriction (HPV). We asked whether deletion of PKC-ε would decrease acute HPV in adult C57BL6×SV129 mice. In isolated, salt solution-perfused lung, reactivity to acute hypoxic challenges (0% and 3% O2) was compared with responses to angiotensin II (ANG II) and KCl. PKC-ε −/− mice had decreased HPV, whereas responses to ANG II and KCl were preserved. Inhibition of nitric oxide synthase (NOS) with nitro-l-arginine augmented HPV in PKC-ε +/+ but not −/− mice. Inhibition of Ca2+-gated K+ channels (KCa) with charybdotoxin and apamin did not enhance HPV in −/− mice relative to wild-type (+/+) controls. In contrast, the voltage-gated K+channel (KV) antagonist 4-aminopyridine increased the response of −/− mice beyond that of +/+ mice. This suggested that increased KV channel expression could contribute to blunted HPV in PKC-ε −/− mice. Therefore, expression of the O2-sensitive KV channel subunit Kv3.1b (100-kDa glycosylated form and 70-kDa core protein) was compared in whole lung and pulmonary artery smooth muscle cell (PASMC) lysates from +/+ and −/− mice. A subtle increase in Kv3.1b was detected in −/− vs. +/+ whole lung lysates. A much greater rise in Kv3.1b expression was found in −/− vs. +/+ PASMC. Thus deletion of PKC-ε blunts murine HPV. The decreased response could not be attributed to a general loss in vasoreactivity or derangements in NOS or KCa channel activity. Instead, the absence of PKC-ε allows increased expression of KV channels (like Kv3.1b) to occur in PASMC, which likely contributes to decreased HPV.

Acute and long-term TNF-alpha administration increases pulmonary vascular reactivity in isolated rat lungs

1992 ◽  
Vol 73 (2) ◽  
pp. 708-712 ◽  
Author(s):  
T. Stevens ◽  
P. L. Janssen ◽  
A. Tucker
Keyword(s):  
Pulmonary Hypertension ◽  
Vascular Reactivity ◽  
Acute Hypoxia ◽  
Tnf Alpha ◽  
Ang Ii ◽  
Necrosis Factor Alpha ◽  
Arterial Hypoxemia ◽  
Pressor Responses

Tumor necrosis factor-alpha (TNF-alpha) causes pulmonary hypertension and arterial hypoxemia, but the mechanisms are unknown. We conducted two experiments to test the hypothesis that TNF-alpha alters pulmonary vascular reactivity, which in turn could cause either pulmonary hypertension or arterial hypoxemia. In experiment 1, rats were given acute or long-term injections of TNF-alpha (recombinant human) in vivo. Rats treated acutely received either saline or TNF-alpha (40 micrograms/kg iv in saline) 3 min (TNF-3 min; n = 8), 20 min (TNF-20 min; n = 8), or 24 h (TNF-24 h; n = 5) before the lungs were isolated. Rats treated chronically received injections of either saline or TNF-alpha (250 micrograms/kg ip in saline) two times per day for 7 days (TNF-7 days; n = 9). Lungs were isolated and perfused with Earle's salt solution (+2 g/l NaHCO3 + 4 g/100 ml Ficoll), and vascular reactivity was tested with acute hypoxia (3 min; 3% O2) and angiotensin II (ANG II; 0.025–0.40 micrograms). Pulmonary pressor responses to hypoxia were greater (P less than 0.05) in TNF-20 min and TNF-7 day groups. ANG II responses were increased (P less than 0.05) in TNF-7 day rats. In experiment 2, lungs were isolated and perfused and received direct pulmonary arterial injections of TNF-alpha (0.2, 2.0, and 20 micrograms) or saline, after stable responses to hypoxia and ANG II (0.10 microgram) were attained. Reactivity was not different between control and TNF-alpha rats before the injections, but TNF-alpha increased (P less than 0.05) responses to hypoxia and ANG II.(ABSTRACT TRUNCATED AT 250 WORDS)

Intact lung cytochrome P-450 is not required for hypoxic pulmonary vasoconstriction

1992 ◽  
Vol 263 (4) ◽  
pp. L446-L453 ◽  
Author(s):  
S. W. Chang ◽  
D. Dutton ◽  
H. L. Wang ◽  
L. S. He ◽  
R. Stearns ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Vascular Reactivity ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Organ Bath ◽  
Pulmonary Vasoconstriction ◽  
Rat Lungs ◽  
Persistent Depression ◽  
Pulmonary Arterial ◽  
Suicide Substrate ◽  
Cytochrome P 450

Lung cytochrome P-450 has been suggested to play a role in hypoxic pulmonary vasoconstriction. We reexamined this hypothesis using specific suicide substrate inhibitors of cytochrome P-450, 1-aminobenzotriazole (1-ABT), and chloramphenicol. In isolated, blood-perfused rat lungs, 1-ABT (0.5 mg/ml) and chloramphenicol (1 mg/ml) inhibited lung microsomal cytochrome P-450 (ethoxycoumarin O-deethylase) activity to 24 and 44% of control, respectively, and blunted hypoxia and angiotensin II-induced vasoconstriction. The depression of vascular contraction by 1-ABT was not due to an effect on calcium channels, since similar concentrations of 1-ABT had no inhibitory activity on electrical field-stimulated contractile response in rabbit papillary muscle strips. However, when 1-ABT was washed out of the lung after preincubation, the vascular reactivity to hypoxia and angiotensin II was restored despite persistent depression of lung cytochrome P-450 activity to 26% of control values. In isolated rat aortic and pulmonary arterial rings, addition of 1-ABT or metyrapone to the organ bath acutely reversed norepinephrine-induced contraction but preincubation with 1-ABT, metyrapone, or chloramphenicol had no effect on subsequent norepinephrine contractions. We conclude that 1-ABT inhibited lung vascular reactivity by a mechanism independent of cytochrome P-450 inhibition or calcium channel blockade and that an intact lung cytochrome P-450 system is not required for hypoxic pulmonary vasoconstriction in rat lungs.

Sign in / Sign up

Export Citation Format

Share Document