Loop diuretics attenuate bradykinin-induced increase in clearance of macromolecules in the oral mucosa

1996 ◽  
Vol 80 (3) ◽  
pp. 818-823 ◽  
Author(s):  
X. P. Gao ◽  
J. M. Conlon ◽  
J. K. Vishwanatha ◽  
R. A. Robbins ◽  
I. Rubinstein

The purpose of this study was to determine whether loop diuretics attenuate bradykinin-induced increase in clearance of macromolecules in the oral mucosa in situ and, if so, to start to determine the mechanisms that mediated these responses. By using intravital microscopy, we found that bradykinin induced a significant concentration-dependent increase in fluorescein isothiocyanate-labeled dextran (mol mass 70 kDa) leaky site formation in the hamster cheek pouch. These responses were significantly attenuated by topical application of two structurally distinct loop diuretics, furosemide and ethacrynic acid, onto the cheek pouch (P < 0.05). Hydrochlorothiazide, a nonloop diuretic, had no significant effects on bradykinin-induced responses. Furosemide had no significant effects on adenosine-induced leaky site formation. Application of bradykinin after furosemide, but not after hydrochlorothiazide, was associated with a significant concentration-dependent decrease in bradykinin-like immunoreactivity in the cheek pouch suffusate (P < 0.05). Prostaglandins and changes in vasomotor tone did not modulate the effects of furosemide on bradykinin-induced responses. These data indicate that loop diuretics attenuate bradykinin-induced increase in clearance of macromolecules in the oral mucosa in a specific fashion, probably by amplifying local bradykinin catabolism. We suggest that topical loop diuretics could be useful in the treatment of oral mucosa inflammation elicited by bradykinin.

1997 ◽  
Vol 272 (1) ◽  
pp. R294-R301
Author(s):  
X. P. Gao ◽  
I. Rubinstein

The purpose of this study was to determine whether interleukin-1 beta (IL-1 beta) elicits macromolecular efflux from the in situ oral mucosa and whether it amplifies that evoked by bradykinin. Using intravital microscopy, we found that suffusion of recombinant human IL-1 beta (50 ng/ml) had no significant effects on leaky site formation and increase in clearance of fluorescein isothiocyanate-labeled dextran (mol mass 70 kDa) from the hamster cheek pouch. However, it significantly potentiated bradykinin-induced macromolecular efflux (P < 0.05). The potentiating effects of IL-1 beta on bradykinin-induced responses were abrogated by a bradykinin B2-receptor antagonist and by a recombinant human IL-1-receptor antagonist. They were not mediated by substance P, prostaglandins, or changes in vasomotor tone. IL-1 beta had no significant effects on adenosine-induced macromolecular efflux. Collectively, these data indicate that IL-1 beta potentiates bradykinin-induced macromolecular efflux from the in situ hamster oral mucosa in a specific fashion. We suggest that this interaction could play a role in the pathogenesis of oral mucosa inflammation.


1997 ◽  
Vol 273 (4) ◽  
pp. R1254-R1262 ◽  
Author(s):  
Xiao-Pei Gao ◽  
Israel Rubinstein

The purpose of this study was to determine whether methotrexate modulates bradykinin-induced increase in macromolecular efflux from the in situ oral mucosa and whether this response is mediated by thel-arginine/nitric oxide biosynthetic pathway. Using intravital microscopy, we found that suffusion of methotrexate alone onto the hamster cheek pouch had no significant effects on leaky site formation and increase in clearance of fluorescein isothiocyanate-labeled dextran (molecular mass, 70 kDa). However, methotrexate significantly potentiated bradykinin-induced responses ( P < 0.05). These effects were associated with significant increases in nitrites concentration and guanosine 3′,5′-cyclic monophosphate-like immunoreactivity in the suffusate and were abrogated by N G-nitro-l-arginine methyl ester (l-NAME) but not N G-nitro-d-arginine methyl ester (d-NAME).l-Arginine, but notd-arginine, abolishedl-NAME-induced responses. ZnCI2 and indomethacin had no significant effects on methotrexate-induced responses. Methotrexate had no significant effects on adenosine- and ionomycin-induced increases in macromolecular efflux. Collectively, these data indicate that methotrexate amplifies bradykinin-induced increase in macromolecular efflux from the in situ oral mucosa in a specific, receptor- andl-arginine/nitric oxide biosynthetic pathway-dependent fashion.


2000 ◽  
Vol 7 (5) ◽  
pp. 794-802 ◽  
Author(s):  
Israel Rubinstein

ABSTRACT The purpose of this study was to determine whether subtilisin, a potent serine proteinase derived from Bacillus species contaminating smokeless tobacco, increases macromolecular efflux from the oral mucosa and, if so, whether local elaboration of bradykinin mediates this response. Using intravital microscopy, I found that suffusion of subtilisin elicits significant, concentration-dependent leaky site formation and an increase in the clearance of fluorescein isothiocyanate-labeled dextran (molecular mass, 70 kDa) from the in situ hamster cheek pouch (P < 0.05). Heat-inactivated subtilisin had no significant effects on macromolecular efflux. Subtilisin-induced responses were significantly attenuated by Hoe 140 and NPC 17647, two structurally distinct selective bradykinin B2 receptor antagonists, but not by des-Arg9-[Leu8]bradykinin, a selective bradykinin B1 receptor antagonist, or CP-96,345, a selective neurokinin-1 receptor antagonist. Aprotinin, but not leupeptin, significantly attenuated subtilisin-induced increase in macromolecular efflux. Indomethacin had no significant effects on subtilisin-induced responses. Collectively, these data indicate that subtilisin increases the macromolecular efflux from the in situ hamster cheek pouch in a catalytic-site-dependent fashion through local elaboration of bradykinin. This response does not involve the stimulation of local afferent nerves or the production of prostaglandins.


1999 ◽  
Vol 87 (2) ◽  
pp. 619-625 ◽  
Author(s):  
Xiao-Pei Gao ◽  
Syed R. Akhter ◽  
Hiroyuki Ikezaki ◽  
Dennis Hong ◽  
Israel Rubinstein

The purpose of this study was to determine whether dexamethasone attenuates the acute increase in macromolecular efflux from the oral mucosa elicited by an aqueous extract of smokeless tobacco (STE) in vivo, and, if so, whether this response is specific. Using intravital microscopy, we found that 20-min suffusion of STE elicited significant, concentration-related leaky site formation and an increase in clearance of fluorescein isothiocyanate-labeled dextran (FITC-dextran; mol mass 70 kDa) from the in situ hamster cheek pouch ( P < 0.05). This response was significantly attenuated by dexamethasone (10 mg/kg iv). Dexamethasone also attenuated the bradykinin-induced leaky site formation and the increase in clearance of FITC-dextran from the cheek pouch. However, it had no significant effects on adenosine-induced responses. Dexamethasone had no significant effects on baseline arteriolar diameter and on bradykinin-induced vasodilation in the cheek pouch. Collectively, these data indicate that dexamethasone attenuates, in a specific fashion, the acute increase in macromolecular efflux from the in situ oral mucosa evoked by short-term suffusion of STE. We suggest that corticosteroids mitigate acute oral mucosa inflammation elicited by smokeless tobacco.


2001 ◽  
Vol 69 (2) ◽  
pp. 1199-1201 ◽  
Author(s):  
Israel Rubinstein ◽  
Jan Potempa ◽  
James Travis ◽  
Xiao-Pei Gao

ABSTRACT Suffusion of gingipain RgpA (GRgpA) elicited a significant concentration-dependent increase in the clearance of macromolecules from in situ hamster cheek pouch which was attenuated by NPC 17647, a selective bradykinin B2 receptor antagonist. Leupeptin and a mixture of proteinase inhibitors also attenuated GRgpA-induced responses. These data indicate that GRgpA elicits plasma exudation from in situ oral mucosa in a catalytic site-dependent fashion by elaborating bradykinin.


1997 ◽  
Vol 83 (1) ◽  
pp. 74-81 ◽  
Author(s):  
Xiao-Pei Gao ◽  
Hideyuki Suzuki ◽  
Christopher O. Olopade ◽  
Sergei Pakhlevaniants ◽  
Israel Rubinstein

Gao, Xiao-pei, Hideyuki Suzuki, Christopher O. Olopade, Sergei Pakhlevaniants, and Israel Rubinstein. Purified ACE attenuates smokeless tobacco-induced increase in macromolecular efflux from the oral mucosa. J. Appl. Physiol. 83(1): 74–81, 1997.—The purpose of this study was to determine whether purified angiotensin I-converting enzyme (ACE) attenuates smokeless tobacco extract (STE)-induced increase in macromolecular efflux from the in situ oral mucosa. By using intravital microscopy, we found that suffusion of an aqueous extract of smokeless tobacco elicited significant concentration-dependent leaky site formation and increase in clearance of fluorescein isothiocyanate-labeled dextran (mol mass, 70 kDa) from the hamster cheek pouch ( P< 0.05). Suffusion of purified rabbit lung ACE significantly attenuated these responses in a concentration-dependent fashion ( P < 0.05). These effects were specific because purified ACE also significantly attenuated the increase in macromolecular efflux elicited by bradykinin, which is produced in the cheek pouch during suffusion of STE, but did not attenuate the increase elicted by adenosine. Moreover, suffusion of heat-inactivated purified ACE and purified superoxide dismutase had no significant effects on STE- and bradykinin-induced responses. Collectively, these data suggest that exogenous ACE attenuates STE-induced increase in macromolecular efflux from the in situ oral mucosa, in part, by promoting local bradykinin catabolism.


1998 ◽  
Vol 274 (1) ◽  
pp. R104-R111 ◽  
Author(s):  
Israel Rubinstein ◽  
Xiao-Pei Gao ◽  
Sergei Pakhlevaniants ◽  
Dolphine Oda

The purpose of this study was to determine whether supernatants of cultured human oral keratinocytes (HOK) exposed to an aqueous extract of smokeless tobacco (STE) increase macromolecular efflux from the oral mucosa in vivo and, if so, whether bradykinin mediates in part this response. Subconfluent monolayers of HOK were incubated with STE or media, and supernatants were collected 24, 48, and 72 h thereafter. Using intravital microscopy, we found that suffusion of supernatants of STE- but not media-exposed HOK elicited significant concentration- and time-dependent increases in efflux of fluorescein isothiocyanate-labeled dextran (mol mass 70 kDa) from the in situ hamster cheek pouch ( P < 0.05). These effects were significantly attenuated by HOE-140 and NPC-17647 but not by des-Arg9,[Leu8]-bradykinin. Proteolytic activity was increased in supernatants of STE- but not media-exposed HOK. However, a mixture of leupeptin, Bestatin, anddl-2-mercaptomethyl-3-guanidinoethylthiopropanoic acid had no significant effects on HOK supernatant-induced responses. Collectively, these data suggest that oral keratinocytes modulate smokeless tobacco-induced increase in macromolecular efflux from the in situ oral mucosa in part by elaborating proteases that may account for local bradykinin production.


1998 ◽  
Vol 274 (1) ◽  
pp. R237-R242
Author(s):  
Xiao-Pei Gao

The purpose of this study was to determine whether tannic acid elicits neurogenic plasma exudation from the oral mucosa in vivo and, if so, whether this response is transduced in part by thel-arginine-nitric oxide (NO) biosynthetic pathway. Using intravital microscopy, we found that suffusion of tannic acid elicits significant concentration-dependent leaky site formation and increase in clearance of fluorescein isothiocyanate-dextran (molecular mass 70 kDa) from the in situ hamster cheek pouch ( P < 0.05). These effects are significantly attenuated by two selective, but structurally distinct, nonpeptide neurokinin-1 (NK1) receptor antagonists, CP-96,345 and RP-67580, but not by CP-96,344, the 2R,3R enantiomer of CP-96,345. N G-nitrol-arginine methyl ester (l-NAME), an NO synthase inhibitor, but notd-NAME, significantly attenuates tannic acid-induced responses.l-Arginine, but notd-arginine, reverses the attenuating effects of l-NAME. We conclude that tannic acid elicitsl-arginine-NO biosynthetic pathway-dependent neurogenic plasma exudation from the in situ hamster cheek pouch.


1995 ◽  
Vol 78 (2) ◽  
pp. 562-568 ◽  
Author(s):  
X. P. Gao ◽  
I. Rubinstein

The purpose of this study was to investigate whether neutral endopeptidase (NEP; EC 3.4.24.11) modulates substance P-induced vasodilation in the oral mucosa in vivo. Using intravital microscopy, we measured the diameter of second-order arterioles (44–70 microns) in the hamster cheek pouch during suffusion of capsaicin and substance P. We found that capsaicin (0.1 and 10.0 nM) induced significant concentration-dependent vasodilations (13 +/- 4 and 39 +/- 7% increase from baseline, respectively; P < 0.05) that were significantly potentiated by phosphoramidon (10.0 nM), a selective NEP inhibitor (35 +/- 15 and 61 +/- 12% increase from baseline, respectively; P < 0.05). Substance P (0.1 and 10.0 nM) also induced significant concentration-dependent vasodilations (7 +/- 3 and 25 +/- 8% increase from baseline, respectively; P < 0.05) that were mediated by the COOH-terminal of the molecule. Substance P-induced responses were significantly potentiated by phosphoramidon (34 +/- 9 and 53 +/- 10% increase from baseline, respectively; P < 0.05) and thiorphan (10.0 microM), a selective NEP inhibitor (44 +/- 11 and 53 +/- 10% increase from baseline, respectively; P < 0.05). Substance P-(1–9) had no significant effects on arteriolar diameter. Suffusion of captopril, leupeptin, Bestatin, and DL-2-mercaptomethyl-3-guanidinoethylthiopropanoic acid together had no significant effects on substance P-induced vasodilation. Phosphoramidon did not potentiate nitroglycerin-induced vasodilation. These data indicate that NEP modulates substance P-induced vasodilation in the hamster cheek pouch in vivo. We suggest that any decrease in tissue NEP activity may amplify neurogenic vasodilation in the oral mucosa.


2001 ◽  
Vol 91 (2) ◽  
pp. 552-560 ◽  
Author(s):  
Israel Rubinstein ◽  
Rinku Chandilawa ◽  
Sumeet Dagar ◽  
Dennis Hong ◽  
Xiao-Pei Gao

The purpose of this study was to pharmacologically characterize the adenosine receptor subtype(s) that mediates adenosine-induced increases in macromolecular efflux from the intact hamster cheek pouch. Using intravital microscopy, we found that 1,3-dipropyl-8-(2-amino-4-chlorophenyl)-xanthine (PACPX), a selective adenosine receptor-1 antagonist, but not 3,7-dimethyl-1-propargylxanthine (DMPX), a selective adenosine receptor-2 antagonist, significantly attenuated adenosine-induced leaky site formation and increased clearance of fluorescein isothiocyanate-labeled dextran (molecular mass, 70 kDa) from the intact hamster cheek pouch ( P < 0.05). Both compounds had no significant effects on bradykinin-induced responses. Nanomolar concentrations of R(−)- N 6-(2-phenylisopropyl)-adenosine [R(−)-PIA], a selective adenosine A1 agonist, evoked significant, concentration-dependent increases in macromolecular efflux. This response was significantly attenuated by PACPX but not by DMPX. In contrast, CGS-21680, a selective adenosine A2agonist, increased macromolecular efflux but only at micromolar concentrations. This response was significantly attenuated by DMPX but not by PACPX. Suffusion of nitroglycerin had no significant effects on R(−)-PIA- and CGS-21680-induced responses. In addition, suffusion of N G-nitro-l-arginine methyl ester, a nitric oxide synthase inhibitor, had no significant effects on adenosine-induced responses. Indomethacin had no significant effects on adenosine-, R(−)-PIA-, and CGS-21680-induced increases in macromolecular efflux. Collectively, these data indicate that adenosine increases macromolecular efflux from the intact hamster cheek pouch by stimulating high-affinity adenosine A1 receptors in a specific, nitric oxide- and prostaglandin-independent fashion.


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