Neurokinin receptors subserving plasma extravasation in guinea pig airways

1995 ◽  
Vol 73 (7) ◽  
pp. 927-931 ◽  
Author(s):  
Ian W. Rodger ◽  
Christine Tousignant ◽  
Donna Young ◽  
Chantal Savoie ◽  
Chi-Chung Chan

In the respiratory system the tachykinins substance P and neurokinin A exhibit a variety of effects on airway function that include bronchoconstriction, vasodilatation, and plasma extravasation. Increased microvascular permeability with accompanying plasma extravasation is a principal cause of tissue edema observed in asthma. In guinea pig airways it has been suggested that neurogenic plasma extravasation is mediated by tachykinins, released from sensory nerve terminals, acting via neurokinin (NK) receptors. We have characterized NK receptor mediated plasma extravasation in guinea pig airways, using 125I-labelled human fibrinogen as a marker for leakage. Extravasation was induced using selective NK1 and NK2 receptor agonists, capsaicin, or nonadrenergic, noncholinergic nerve stimulation. The inhibitory effects of the selective nonpeptide NK receptor antagonists (CP 99,994 for NK1 and. SR 48,968 for NK2) were also examined. Results from our studies demonstrate conclusively that only NK1 receptors subserve plasma extravasation in the trachea and large airways of the guinea pig. In stark contrast, extravasation in the lower airways (secondary bronchi and intraparenchymal airways) of the guinea pig is mediated by both NK1 and NK2 receptors.Key words: tachykinins, substance P, neurokinin A, plasma extravasation, neurokinin receptors, asthma.

1991 ◽  
Vol 70 (3) ◽  
pp. 1215-1219 ◽  
Author(s):  
M. A. Martins ◽  
S. A. Shore ◽  
J. M. Drazen

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.


1993 ◽  
Vol 71 (7) ◽  
pp. 506-511 ◽  
Author(s):  
Christine Tousignant ◽  
Chi-Chung Chan ◽  
Donna Young ◽  
Diane Guevremont ◽  
Ian W. Rodger

In the present study we have characterized NK-1 and NK-2 receptor induced microvascular leakage in guinea pig and rat airways, using 125I-labelled human fibrinogen ([125I]FN) versus 99mTc-labelled human serum albumin ([99mTc]HSA) as markers for plasma protein extravasation. Intravenous administration of the selective NK-1 agonist [Sar9, Met(O2)11]SP (1 nmol kg−1) caused a dose-dependent increase of [125I]FN extravasation in guinea pig trachea, main bronchi, secondary bronchi, and intraparenchymal airways. Extravasation of [125I]FN increased by up to 192 (trachea), 284 (main bronchi), 368 (secondary bronchi), and 271% (intraparenchymal bronchi) over control levels in these regions of the airways. Pretreatment of the animals with CP 99,994 and RP 67,580, two NK-1 nonpeptide antagonists, caused a dose-dependent inhibition of [Sar9, Met(O2)11]SP-induced leakage of [125I]FN. [Sar9, Met(O2)11]SP (1 nmol kg−1) did not induce specific leakage of [99mTc]HSA in the intraparenchymal bronchi. Specific NK-2 receptor induced leakage was detected in the lower airways but only when using [125I]FN as a marker. We have also compared the ability of CP 99,994 and RP 67,580 to inhibit [Sar9, Met(O2)11]SP induced extravasation of [125I]FN in rat airways. CP 99,994 was 40–50 (tracheobronchial region) to 75 (lower airways) times more potent in the guinea pig than the rat airways. In contrast, RP 67,580 had higher affinity for rat airways compared with guinea pig airways. The results of this study highlight the superiority of [125I]FN as a sensitive marker of plasma extravasation over [99mTc]HSA. Furthermore, the results strongly suggest that both NK-1 and NK-2 receptors mediate plasma extravasation in the guinea pig lower airways and that NK-1 receptors are different in guinea pig and rat airways.Key words: Leakage, tachykinins, NK-1 and NK-2 receptors, airway, asthma.


1995 ◽  
Vol 268 (2) ◽  
pp. L263-L269 ◽  
Author(s):  
P. Baluk ◽  
C. Bertrand ◽  
P. Geppetti ◽  
D. M. McDonald ◽  
J. A. Nadel

In neurogenic inflammation, tachykinins trigger the adhesion of neutrophils and eosinophils to leaky venules. The goals of the present study were to determine whether this leukocyte adhesion is mediated by neurokinin type 1 (NK1) receptors and to determine whether the amount of leukocyte adhesion corresponds to the amount of plasma leakage. Anesthetized rats were injected intravenously with substance P, the NK1 receptor agonist [Sar9, Met(O2)11]-substance P, or the NK2 receptor agonist [beta-Ala8]neurokinin A-(4–10). Five minutes later, the adherent neutrophils and eosinophils in blood vessels of the tracheal mucosa were stained histochemically and plasma leakage was quantified, as assessed by the extravasation of Monastral blue. Substance P and the NK1 agonist caused similar amounts of leukocyte adhesion, but the NK2 agonist had no effect. Pretreatment with the NK1 receptor antagonist CP-96,345 (4 mg/kg iv), before challenge with substance P, capsaicin, or aerosol hypertonic saline, reduced the amount of neutrophil adhesion by 56%, 93%, and 57% and reduced the amount of eosinophil adhesion by 70%, 83%, and 65%, respectively. Plasma extravasation was decreased by 89%, 95%, and 94%. The number of adherent neutrophils in the trachea was strongly correlated with the number of adherent eosinophils (r2 = 0.61). The greatest amount of leukocyte adhesion occurred in larger diameter venules than did the maximal amount of Monastral blue leakage. We conclude that NK1 receptors mediate the adhesion of neutrophils and eosinophils as well as the plasma leakage triggered by substance P, capsaicin, or hypertonic saline. This leukocyte adhesion evidently does not occur at exactly the same sites as the plasma leakage.


1993 ◽  
Vol 265 (2) ◽  
pp. H593-H598
Author(s):  
X. P. Gao ◽  
R. A. Robbins ◽  
R. M. Snider ◽  
J. Lowe ◽  
S. I. Rennard ◽  
...  

The purpose of this study was to determine the receptor subtype(s) that mediates tachykinin-induced neurogenic plasma extravasation in the hamster cheek pouch. Changes in microvascular clearance were quantified by counting the number of leaky sites and calculating the clearance of fluorescein isothiocyanate-dextran [mol wt 70,000 (Dextran 70)] during suffusion of the cheek pouch with substance P, neurokinin A, neurokinin B, and capsaicin. Suffusion of substance P, capsaicin, and neurokinin A, but not neurokinin B, was associated with a significant concentration-dependent increase in leaky site formation and clearance of fluorescein isothiocyanate-Dextran 70 (P < 0.05). However, the responses to substance P and capsaicin were significantly greater than those to neurokinin A. Pretreatment with the selective, nonpeptide NK1 receptor antagonist, CP-96,345, significantly attenuated substance P- and capsaicin-induced but not neurokinin A-induced responses (P < 0.05). These effects were specific, since the 2R,3R enantiomer, CP-96,344, was inactive, and CP-96,345 had no significant effect on adenosine-induced responses. We conclude that, in the hamster cheek pouch, NK1 receptors are the predominant receptors that mediate neurogenic plasma extravasation.


1992 ◽  
Vol 37 ◽  
pp. S154
Author(s):  
K. Takahama ◽  
J. Fuchikami ◽  
Y. Isohama ◽  
H. Kai ◽  
T. Miyata

1995 ◽  
Vol 78 (4) ◽  
pp. 1234-1241 ◽  
Author(s):  
C. M. Lilly ◽  
A. E. Hall ◽  
I. W. Rodger ◽  
L. Kobzik ◽  
K. J. Haley ◽  
...  

The capacity of substance P (SP) and endogenously released tachykinins to liberate histamine was examined in isolated tracheally perfused guinea pig lungs. Increasing doses of tracheally injected SP were associated with the recovery of increasing amounts of histamine from lung effluent. The mechanism of SP-induced histamine liberation was explored in studies with neurokinin-(NK) receptor agonists and antagonists. Tracheal injection of either the NK1 agonist [Sar9,Met(O2)11]SP or the NK2 agonist [beta-Ala8]-neurokinin A-(4–10) was associated with a significant increase in histamine recovery from lung effluent. In addition, both the NK1 antagonist CP-99994 and the NK2 antagonist SR-48968 significantly inhibited SP-induced histamine release. These findings support the hypothesis that SP can liberate histamine from guinea pigs lungs by a mechanism that depends predominantly on NK1- and NK2-receptor activation. The liberation of endogenous tachykinins by acute tracheal injection of capsaicin was also associated with augmented histamine recovery, which was inhibited by combined NK1- and NK2-receptor blockade. Tracheal injection of SP was associated with an increase in the percentage of airway mast cells exhibiting histological evidence of degranulation. This study demonstrates that exogenous SP, as well as endogenous tachykinins released from capsaicin-sensitive neurons, can liberate histamine, most likely from airway mast cells, by a mechanism that depends predominantly on the activation of NK1 and NK2 receptors.


1987 ◽  
Vol 62 (2) ◽  
pp. 746-751 ◽  
Author(s):  
Y. L. Lai ◽  
A. F. Cornett

To further examine the role that substance P plays in initiating the observed massive postmortem bronchoconstriction in guinea pig lungs and to explore the role of neural reflex in this airway spasm, six groups of animals were employed: control (n = 6), morphine (n = 6), substance P (n = 5), chronic capsaicin pretreatment + substance P (n = 5), tetrodotoxin (TTX) + acute capsaicin (n = 4), and chlorisondamine + acute capsaicin (n = 5). Pressure-volume curves were performed prior to and following the initiation of artificial pulmonary perfusion with 1% bovine serum albumin and 5% dextran in Tyrode's solution. A decrease in inflation volume (the lung volume between transpulmonary pressure of 0 and 30 cmH2O during inflation) was used as an index of bronchoconstriction. In control animals, inflation volume decreased to 20–30% of the base-line value at 15–30 min of perfusion, indicating massive bronchial constriction during this time period. Morphine (an agent inhibiting substance P release) significantly attenuated the spasm, whereas the presence of substance P in the perfusate markedly enhanced the constriction. Depletion of endogenous substance P by chronic capsaicin pretreatment did not affect exogenous substance P-induced spasm. Acute capsaicin-induced bronchoconstriction was significantly attenuated by TTX but was not affected by the ganglionic blocking agent, chlorisondamine. These data suggest that substance P initiates the massive postmortem bronchoconstriction in guinea pig lungs and that substance P is released by local stimulation of sensory nerve endings via axonal reflex.


1995 ◽  
Vol 73 (7) ◽  
pp. 903-907 ◽  
Author(s):  
M. Qtsuka ◽  
K. Yoshioka ◽  
M. Yanagisawa ◽  
H. Suzuki ◽  
F.-Y. Zhao ◽  
...  

Tachykinin NK1 receptor antagonists were used to explore the physiological functions of substance P (SP) and neurokinin A (NKA). Pharmacological profiles of three NK1 receptor antagonists, GR71251, GR82334, and RP 67580, were examined in the isolated spinal cord preparation of the neonatal rat. These tachykinin receptor antagonists exhibited considerable specificities and antagonized the actions of both SP and NKA to induce the depolarization of ventral roots. Electrical stimulation of the saphenous nerve with C-fiber strength evoked a depolarization lasting about 30 s of the ipsilateral L3 ventral root. This response, which is referred to as saphenous-nerve-evoked slow ventral root potential (VRP), was depressed by these NK1 receptor antagonists. In contrast, the saphenous-nerve-evoked slow VRP was potentiated by application of a mixture of peptidase inhibitors, including thiorphan, actinonin, and captopril in the presence of naloxone, but not after further addition of GR71251. Likewise, in the isolated coeliac ganglion of the guinea pig, electrical stimulation of the mesenteric nerves evoked in some ganglionic cells slow excitatory postsynaptic potentials (EPSPs), which were depressed by GR71251 and potentiated by peptidase inhibitors. These results further support the notion that SP and NKA serve as neurotransmitters producing slow EPSPs in the neonatal rat spinal cord and guinea pig prevertebral ganglia.Key words: substance P, neurokinin A, neurotransmitter, tachykinin antagonist, spinal cord.


2006 ◽  
Vol 47 (3) ◽  
pp. 856-864 ◽  
Author(s):  
R. Nau ◽  
G. Schäfer ◽  
C. F. Deacon ◽  
T. Cole ◽  
D. V. Agoston ◽  
...  

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