Tachykinin recovery during postmortem bronchoconstriction in guinea pig lungs

1991 ◽  
Vol 70 (3) ◽  
pp. 1215-1219 ◽  
Author(s):  
M. A. Martins ◽  
S. A. Shore ◽  
J. M. Drazen
Keyword(s):  
Substance P ◽  
Guinea Pig ◽  
Neutral Endopeptidase ◽  
Neurokinin A ◽  
Opening Pressure ◽  
Airway Opening ◽  
Isolated Lungs ◽  
Peak Value

We examined the role of substance P (SP) and neurokinin A (NKA) in the postmortem bronchoconstriction in guinea pig lungs using isolated lungs superfused via the trachea. Airway opening pressure (Pao) during superfusion was monitored and the superfusate collected for analysis of SP- and NKA-like immunoreactivities (SP-LI and NKA-LI, respectively). Peak Pao (39.0 +/- 3.9 cmH2O) was reached 10 min after starting superfusion; Pao decreased slowly thereafter, reaching only 9.9 +/- 2.2% of the peak value 2 h after starting superfusion (P less than 0.005); 12.6 +/- 2.6 and 34.0 +/- 9.7 fmol of SP-LI and NKA-LI, respectively, were found in the fraction corresponding to 10-20 min of superfusion. Recovered immunoreactivities decreased to 5.2 +/- 0.3 and 9.3 +/- 1.8 fmol of SP-LI and NKA-LI, respectively, in the fraction corresponding to 110-120 min of superfusion (P less than 0.05). Inhibition of neutral endopeptidase with thiorphan resulted in significantly greater increases in Pao (P less than 0.005) and augmentation of the recovery of SP-LI and NKA-LI (P less than 0.05 and P less than 0.001, respectively). Capsaicin treatment of animals 7-10 days before the removal of their lungs abolished the increase in Pao during superfusion and resulted in a significant decrease in the amount of SP-LI and NKA-LI recovered. Our data confirm that tachykinin release occurs during postmortem bronchoconstriction in guinea pig lungs and, furthermore, that tachykinin degradation by NEP modulates the intensity of this response.

Release of tachykinins by histamine, methacholine, PAF, LTD4, and substance P from guinea pig lungs

1991 ◽  
Vol 261 (6) ◽  
pp. L449-L455 ◽  
Author(s):  
M. A. Martins ◽  
S. A. Shore ◽  
J. M. Drazen
Keyword(s):  
Substance P ◽  
Guinea Pig ◽  
Platelet Activating Factor ◽  
Neutral Endopeptidase ◽  
Neurokinin A ◽  
Opening Pressure ◽  
Leukotriene D4 ◽  
Airway Opening

The release of substance P- and neurokinin A-like immunoreactivities (SP-LI and NKA-LI) after tracheal infusion of histamine, methacholine, leukotriene D4, and platelet-activating factor was measured in isolated guinea pig lungs superfused through the trachea. Infusion of each of these agonists was associated with a significant (P less than 0.05) increase in the recovery of both SP-LI and NKA-LI from lung perfusates compared with preinfusion baseline recoveries of these peptides. After infusion of bronchoactive mediators, approximately 4-15 times more NKA-LI than SP-LI was recovered from the lung superfusate. Coincident with the release of neuropeptides, mediator infusion was accompanied by an increase in airway opening pressure (Pao). Addition to the perfusate of the neutral endopeptidase inhibitor thiorphan, 1 microM increased the change in Pao induced by histamine (10(-8) mol, P less than 0.005) and methacholine (10(-8) mol, P less than 0.02) and increased the recovery of NKA-LI (P less than 0.05 for histamine and methacholine). Addition of isoproterenol to the perfusion buffer reduced, but did not abolish, either the Pao response or the increased recovery of NKA-LI (P less than 0.05) observed after histamine infusion. We conclude that bronchoactive agonists have the capacity to release both SP-LI and NKA-LI, and we speculate that NKA contributes to the bronchomotor response observed in response to histamine or methacholine.

ROLE OF EXTRACELLULAR CALCIUM IN THE EFFECTS OF SUBSTANCE P AND NEUROKININ A ON GUINEA PIG TRACHEA AND HUMAN BRONCHUS

1988 ◽  
Vol 2 (1) ◽  
pp. 47-55 ◽  
Author(s):  
R. MATRAN ◽  
E. NALINE ◽  
C. ADVENIER ◽  
A. LOCKHART ◽  
J.F. TRICOT ◽  
...  
Keyword(s):  
Substance P ◽  
Guinea Pig ◽  
Extracellular Calcium ◽  
Neurokinin A ◽  
Human Bronchus

Capsaicin-induced release of tachykinins: effects of enzyme inhibitors

1991 ◽  
Vol 70 (5) ◽  
pp. 1950-1956 ◽  
Author(s):  
M. A. Martins ◽  
S. A. Shore ◽  
J. M. Drazen
Keyword(s):  
Mechanical Response ◽  
Enzyme Inhibitors ◽  
Ace Inhibition ◽  
Neutral Endopeptidase ◽  
Neurokinin A ◽  
Opening Pressure ◽  
Airway Opening ◽  
High Doses ◽  
Airway Responses ◽  
Pressure Changes

We studied the effects of neutral endopeptidase (NEP) and angiotensin-converting enzyme (ACE) inhibition on the airway responses and the recovery of endogenously released substance P- and neurokinin A-like immunoreactivities (SP-LI and NKA-LI) after tracheal injection of capsaicin in isolated guinea pig lungs superfused through the trachea. Capsaicin in doses from 10(-10) to 10(-7) mol induced a dose-dependent increase in airway opening pressure and release of SP-LI and NKA-LI. Airway opening pressure changes and the recovery of SP-LI and NKA-LI were significantly greater in lungs superfused with the NEP inhibitor SCH 32615 than in control lungs. ACE inhibition with captopril did not increase the mechanical response or the recovery of SP-LI compared with lungs not receiving captopril. In lungs from guinea pigs pretreated with high doses of capsaicin 7-10 days before study, a regimen designed to deplete endogenous tachykinins, there was a significant decrease in the content and release of NKA-LI and SP-LI. There were no detectable airway effects of acute capsaicin infusion even after doses of 10(-5) mol. Because NEP is important in modulating the airway effects of endogenously released tachykinins after tracheal infusion of capsaicin, but ACE is not, it seems likely that tracheal administration of capsaicin releases tachykinins from epithelial rather than endothelial loci.

Effect of the NEP inhibitor SCH32615 on airway responses to intravenous substance P in guinea pigs

1992 ◽  
Vol 73 (5) ◽  
pp. 1847-1853 ◽  
Author(s):  
S. A. Shore ◽  
M. A. Martins ◽  
J. M. Drazen
Keyword(s):  
Substance P ◽  
Guinea Pigs ◽  
Ace Inhibitor ◽  
Dynamic Compliance ◽  
Neutral Endopeptidase ◽  
Neurokinin A ◽  
Mechanically Ventilated ◽  
Arterial Blood ◽  
Airway Responses ◽  
Nep Inhibition

We examined the effects of the selective neutral endopeptidase (NEP) inhibitor SCH32615 on airway responses to rapid intravenous infusions of substance P (SP) and neurokinin A (NKA) and on recovery of administered tachykinins from arterial blood in anesthetized mechanically ventilated guinea pigs. SCH32615, in doses that cause a marked increase in the magnitude of bronchoconstriction induced by infused NKA, had little effect on the changes in pulmonary conductance (GL) or dynamic compliance induced by SP. In animals in which SCH32615 (1 mg/kg) was administered in combination with the angiotensin-converting enzyme (ACE) inhibitor captopril (5.7 mg/kg), the dose of SP required to decrease GL by 50% was fourfold less than in animals that received captopril alone (P < 0.005). SP measured in arterial blood withdrawn within 45 s of intravenous administration of this tachykinin was not different in control and SCH32615-treated animals, whereas captopril caused an approximately threefold increase in SP concentrations (P < 0.005). When SCH32615 and captopril were administered together, significantly more SP was recovered than when captopril or SCH32615 was administered alone (P < 0.0005). Our results are consistent with the hypothesis that both NEP and ACE contribute to the degradation of intravenously infused SP. ACE degradation of SP is sufficient to limit SP-induced bronchoconstriction even in the presence of specific NEP inhibition.

scholarly journals Role of neutral endopeptidase in endotoxin-induced bronchial hyperresponsiveness to substance P in guinea pigs

1998 ◽  
Vol 47 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Shigenori Iwamae ◽  
Hideo Tsukagoshi ◽  
Takeshi Hisada ◽  
Daisuke Uno ◽  
Masatomo Mori
Keyword(s):  
Substance P ◽  
Guinea Pigs ◽  
Bronchial Hyperresponsiveness ◽  
Neutral Endopeptidase

The role of neutral endopeptidase on endothelin-induced contraction of guinea pig trachealis

1990 ◽  
Vol 22 ◽  
pp. 170
Author(s):  
G.U. Pi Maria ◽  
M. Katayama ◽  
P.D. Graf ◽  
D.B. Borson ◽  
J.A. Nadel
Keyword(s):  
Guinea Pig ◽  
Neutral Endopeptidase

HOCl causes airway substance P hyperresponsiveness and neutral endopeptidase hypoactivity

1990 ◽  
Vol 258 (6) ◽  
pp. L361-L368 ◽  
Author(s):  
C. G. Murlas ◽  
T. P. Murphy ◽  
Z. Lang
Keyword(s):  
Substance P ◽  
Guinea Pig ◽  
Muscle Force ◽  
Hypochlorous Acid ◽  
Neutral Endopeptidase ◽  
Krebs Solution ◽  
Solution Ph ◽  
Reverse Phase ◽  
Tracheal Tissue

We investigated whether exposure of guinea pig tracheal tissue to hypochlorous acid (HOCl) or hydrogen peroxide (H2O2) by perfusion through the airway lumen affected the responsiveness of airway muscle to ACh, KCl, or substance P in the presence or absence of 1 microM phosphoramidon, an inhibitor of neutral endopeptidase (NEP). Pairs of tracheal segments were immersed in a Krebs solution (pH 7.40 at 37 degrees C) and connected to perfusion circuits so that the lumen of one segment of each pair could be perfused with Krebs solution while the other was perfused for the same time (10 min) with either 0.1 microM HOCl or 10 mM H2O2. Segments after perfusion were cut into rings of similar size and placed in muscle chambers so that airway muscle force generation in vitro could be measured on stimulation by cumulative agonist doses. In addition, cell homogenates were made from other, similarly perfused tracheal segments to assess NEP activity using reverse-phase, high-pressure liquid chromatography (HPLC). We found that smooth muscle of mucosa-intact guinea pig airways perfused with HOCl, but not H2O2, was hyperresponsive to substance P but not to ACh or KCl. HOCl-perfused rings were not different from Krebs solution-exposed rings pretreated with phosphoramidon. There was no increase in substance P responsiveness of HOCl-exposed airways in which the mucosa had been removed before testing in vitro. The substance P hyperresponsiveness of HOCl-exposed, mucosa-intact airways was associated with decreased NEP activity.(ABSTRACT TRUNCATED AT 250 WORDS)

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