Effects of phospholipase A2, 12-lipoxygenase, and cyclooxygenase inhibitors in the feline pulmonary bed

1997 ◽  
Vol 272 (4) ◽  
pp. L573-L579 ◽  
Author(s):  
A. D. Kaye ◽  
B. D. Nossaman ◽  
D. E. Smith ◽  
I. N. Ibrahim ◽  
J. D. Imig ◽  
...  
Keyword(s):  
Phospholipase A2 ◽  
Phospholipase C ◽  
Bay K 8644 ◽  
Cyclooxygenase Inhibitors ◽  
Ang Ii ◽  
Lipoxygenase Inhibitor ◽  
Arterial Perfusion ◽  
Vascular Bed ◽  
Phospholipase A2 Inhibitor ◽  
Pulmonary Vascular Bed

The effects of phosphonofluoridic acid, methyl-5,8,11,14-eicosatetraenyl ester (MAFP), a phospholipase A2 inhibitor, on pressor responses to angiotensin II (ANG II), norepinephrine (NE), serotonin (5-HT), the calcium channel opener BAY K 8644, and the thromboxane A2 mimic U-46619 were studied in the pulmonary vascular bed of the intact-chest cat. Under conditions of constant lobar blood flow, injections of ANG II, NE, 5-HT, U-46619, and BAY K 8644 into the lobar arterial perfusion circuit caused dose-related increases in lobar arterial pressure that were reproducible with respect to time. Infusion of MAFP into the perfused lobar artery at doses of 100 to 300 microg/kg for 10 min significantly reduced vasoconstrictor responses to ANG II; however, the phospholipase A2 inhibitor did not alter vasoconstrictor responses to BAY K 8644, 5-HT, NE, or U-46619. The combination of the higher dose of the phospholipase A2 inhibitor MAFP with the phospholipase C inhibitor U-73122 significantly affected vasoconstrictor responses to ANG II, NE, and 5-HT but not to BAY K 8644. In a separate series of animals, the effects of a lipoxygenase inhibitor, baicalein, were investigated. Infusion of baicalein into the perfused lobar artery at doses of 100 microg/kg for 10 min significantly reduced vasoconstrictor responses to ANG II but not the vasoconstrictor responses to BAY K 8644, 5-HT, NE, or U-46619. In a final series of experiments, the effects of a cyclooxygenase inhibitor, meclofenamate, were investigated, and intravenous injection of the meclofenamate at a dose of 2.5 mg/kg did not significantly affect vasoconstrictor responses to ANG II, 5-HT, BAY K 8644, NE, or U-46619. These data provide support for the hypothesis that pulmonary vasopressor responses to ANG II are mediated, in part, by the activation of phospholipase A2, phospholipase C, and the lipoxygenase pathway in the pulmonary vascular bed of the cat.

Influence of PLC and MLCK inhibitors and the role of L-calcium channels in the cat pulmonary vascular bed

1995 ◽  
Vol 269 (4) ◽  
pp. L507-L513 ◽  
Author(s):  
A. D. Kaye ◽  
B. D. Nossaman ◽  
I. N. Ibrahim ◽  
P. J. Kadowitz
Keyword(s):  
Calcium Channel ◽  
Calcium Channel Blocker ◽  
Channel Blocker ◽  
Kinase Inhibitor ◽  
Bay K 8644 ◽  
Ang Ii ◽  
Arterial Perfusion ◽  
Vascular Bed ◽  
Pressor Responses ◽  
Pulmonary Vascular Bed

The effects of U-73122, a phospholipase C (PLC) inhibitor, on pressor responses to angiotensin II (ANG II), norepinephrine (NE), serotonin (5-HT), BAY K 8644, and the thromboxane A2 (TxA2) mimic, U-46619, were studied in the pulmonary vascular bed of the intact-chest cat. Under conditions of constant lobar blood flow, injections of ANG II, NE, 5-HT, U-46619, and the calcium channel opener, BAY K 8644, into the lobar arterial perfusion circuit caused dose-related increases in lobar arterial pressure, which were reproducible with respect to time. Infusion of U-73122, a PLC inhibitor, into the perfused lobar artery at 10–100 micrograms/kg for 10 min significantly reduced responses to ANG II, serotonin, and NE; however, U-73122 did not alter responses to BAY K 8644 or to U-46619. In a separate series of animals, the effects of the myosin light chain kinase inhibitor, KT-5926, were investigated, and after infusion of KT-5926 into the perfused lobar artery at 1–2 micrograms/kg for 10 min, responses to ANG II, NE, 5-HT, BAY K 8644, and U-46619 were reduced significantly. In a final series of experiments, the effects of the L-type calcium channel blocker, nicardipine, were investigated, and infusion of the L-type calcium channel blocker into the perfused lobar artery at 0.5-1 microgram/kg for 10 min reduced responses to ANG II, BAY K 8644, and NE. However, nicardipine did not alter pressor responses to 5-HT or the TxA2 mimic, U-46619.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of PKC isozyme inhibitors on constrictor responses in the feline pulmonary vascular bed

2001 ◽  
Vol 280 (1) ◽  
pp. L50-L57 ◽  
Author(s):  
Bracken J. De Witt ◽  
Alan D. Kaye ◽  
Ikhlass N. Ibrahim ◽  
Trinity J. Bivalacqua ◽  
Fiona M. D'Souza ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Bay K 8644 ◽  
Kinase C ◽  
Vascular Bed ◽  
Flow Perfusion ◽  
Dependent Protein ◽  
Vasopressor Agents ◽  
Pkc Isozymes ◽  
Pulmonary Arterial ◽  
Pulmonary Vascular Bed

The effects of Gö-6976, a Ca2+-dependent protein kinase C (PKC) isozyme inhibitor, and rottlerin, a PKC-δ isozyme/calmodulin (CaM)-dependent kinase III inhibitor, on responses to vasopressor agents were investigated in the feline pulmonary vascular bed. Injections of angiotensin II, norepinephrine (NE), serotonin, BAY K 8644, and U-46619 into the lobar arterial constant blood flow perfusion circuit caused increases in pressure. Gö-6976 reduced responses to angiotensin II; however, it did not alter responses to serotonin, NE, or U-46619, whereas Gö-6976 enhanced BAY K 8644 responses. Rottlerin reduced responses to angiotensin II and NE, did not alter responses to serotonin or U-46619, and enhanced responses to BAY K 8644. Immunohistochemistry of feline pulmonary arterial smooth muscle cells demonstrated localization of PKC-α and -δ isozymes in response to phorbol 12-myristate 13-acetate and angiotensin II. Localization of PKC-α and -δ isozymes decreased with administration of Gö-6976 and rottlerin, respectively. These data suggest that activation of Ca2+-dependent PKC isozymes and Ca2+-independent PKC-δ isozyme/CaM-dependent kinase III mediate angiotensin II responses. These data further suggest that Ca2+-independent PKC-δ isozyme/CaM-dependent kinase III mediate responses to NE. A rottlerin- or Gö-6976-sensitive mechanism is not involved in mediating responses to serotonin and U-46619, but these PKC isozyme inhibitors enhanced BAY K 8644 responses in the feline pulmonary vascular bed.

Nisoldipine inhibits vasoconstrictor responses in the cat pulmonary vascular bed

1989 ◽  
Vol 66 (6) ◽  
pp. 2885-2890 ◽  
Author(s):  
P. J. Kadowitz ◽  
H. L. Lippton ◽  
J. A. Bellan ◽  
A. L. Hyman
Keyword(s):  
Arterial Pressure ◽  
Vascular Resistance ◽  
Blocking Agent ◽  
Systemic Arterial Pressure ◽  
Calcium Entry ◽  
Bay K 8644 ◽  
Vascular Bed ◽  
Adrenoceptor Agonists ◽  
Thromboxane Receptors ◽  
Pulmonary Vascular Bed

The influence of nisoldipine, a dihydropyridine calcium entry antagonist, on vascular resistance and vasoconstrictor responses was investigated in the feline pulmonary vascular bed under conditions of controlled blood flow. The calcium channel blocking agent caused a small reduction in lobar vascular resistance and blocked pulmonary vasoconstrictor responses to BAY K 8644, an agent which promotes calcium entry. The calcium entry blocking agent also reduced pulmonary vasoconstrictor responses to methoxamine and to BHT 933, alpha 1- and alpha 2-adrenoceptor agonists, and to U 46619, an agent which mimics the actions of thromboxane A2. Although there was a marked difference in vasoconstrictor potency in the pulmonary vascular bed, responses to the thromboxane mimic and to the alpha 1- and alpha 2-adrenoceptor agonists were reduced by approximately the same extent. The increases in systemic arterial pressure in response to BAY K 8644, methoxamine, and BHT 933 were also reduced by nisoldipine, and the calcium entry antagonist reduced systemic arterial pressure and systemic vascular resistance. The results of the present study suggest that an extracellular source of calcium is required for the maintenance of vascular tone and for the expression of vasoconstrictor responses, resulting from activation of alpha 1- and postjunctional alpha 2-adrenoceptors and thromboxane receptors in the feline pulmonary vascular bed.

scholarly journals Analysis of responses of garlic derivatives in the pulmonary vascular bed of the rat

2000 ◽  
Vol 89 (1) ◽  
pp. 353-358 ◽  
Author(s):  
Alan D. Kaye ◽  
Bracken J. De Witt ◽  
Muhammad Anwar ◽  
Donald E. Smith ◽  
Chang J. Feng ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Diallyl Disulfide ◽  
Arterial Perfusion ◽  
Vascular Bed ◽  
Pulmonary Vasodilator ◽  
Vasodilator Activity ◽  
Isolated Lung ◽  
Pulmonary Arterial ◽  
Allyl Mercaptan ◽  
Pulmonary Vascular Bed

Allicin, an extract from garlic, has been shown to be a systemic and pulmonary arterial vasodilator that acts by an unknown mechanism. In the present experiments, pulmonary vascular responses to allicin (10–100 μg), allyl mercaptan (0.3–1 mg), and diallyl disulfide (0.3–1 mg) were studied in the isolated lung of the rat under constant-flow conditions. When baseline tone in the pulmonary vascular bed of the rat was raised to a high-steady level with the thromboxane A2mimic U-46619, dose-related decreases in pulmonary arterial pressure were observed. In terms of the mechanism of action of allicin vasodilator activity in the rat, responses to allicin were not significantly different after administration of the nitric oxide synthase inhibitor Nω-nitro-l-arginine methyl ester, the KATP+channel antagonist U-37883A, or the cyclooxygenase inhibitor sodium meclofenamate, or when lung ventilation was interrupted. These data show that allicin has significant vasodilator activity in the pulmonary vascular bed of the rat, whereas allyl mercaptan and diallyl disulfide produced no significant changes in pulmonary arterial perfusion pressure. The present data suggest that pulmonary vasodilator responses to allicin are independent of the synthesis of nitric oxide, ATP-sensitive K+channels, activation of cyclooxygenase enzyme, or changes in bronchomotor tone in the pulmonary vascular bed of the rat.

Stimulation of Ca(2+)-dependent exocytosis of the sperm acrosome by cAMP acting downstream of phospholipase A2

Reproduction ◽  
2000 ◽  
pp. 57-68 ◽  
Author(s):  
J Garde ◽  
ER Roldan
Keyword(s):  
Arachidonic Acid ◽  
Phospholipase A2 ◽  
Phospholipase C ◽  
Phosphodiesterase Inhibitors ◽  
Dibutyryl Camp ◽  
Camp Phosphodiesterase ◽  
Ram Sperm ◽  
Camp Formation ◽  
Stimulation Of

Spermatozoa undergo exocytosis in response to agonists that induce Ca2+ influx and, in turn, activation of phosphoinositidase C, phospholipase C, phospholipase A2, and cAMP formation. Since the role of cAMP downstream of Ca2+ influx is unknown, this study investigated whether cAMP modulates phospholipase C or phospholipase A2 using a ram sperm model stimulated with A23187 and Ca2+. Exposure to dibutyryl-cAMP, phosphodiesterase inhibitors or forskolin resulted in enhancement of exocytosis. However, the effect was not due to stimulation of phospholipase C or phospholipase A2: in spermatozoa prelabelled with [3H]palmitic acid or [14C]arachidonic acid, these reagents did not enhance [3H]diacylglycerol formation or [14C]arachidonic acid release. Spermatozoa were treated with the phospholipase A2 inhibitor aristolochic acid, and dibutyryl-cAMP to test whether cAMP acts downstream of phospholipase A2. Under these conditions, exocytosis did not occur in response to A23187 and Ca2+. However, inclusion of dibutyryl-cAMP and the phospholipase A2 metabolite lysophosphatidylcholine did result in exocytosis (at an extent similar to that seen when cells were treated with A23187/Ca2+ and without the inhibitor). Inclusion of lysophosphatidylcholine alone, without dibutyryl-cAMP, enhanced exocytosis to a lesser extent, demonstrating that cAMP requires a phospholipase A2 metabolite to stimulate the final stages of exocytosis. These results indicate that cAMP may act downstream of phospholipase A2, exerting a regulatory role in the exocytosis triggered by physiological agonists.

scholarly journals α-Conotoxins and α-Cobratoxin Promote, while Lipoxygenase and Cyclooxygenase Inhibitors Suppress the Proliferation of Glioma C6 Cells

Marine Drugs ◽  
2021 ◽  
Vol 19 (2) ◽  
pp. 118
Author(s):  
Tatiana I. Terpinskaya ◽  
Alexey V. Osipov ◽  
Elena V. Kryukova ◽  
Denis S. Kudryavtsev ◽  
Nina V. Kopylova ◽  
...  
Keyword(s):  
Nicotinic Acetylcholine Receptors ◽  
Acetylcholine Receptors ◽  
Glioma Cells ◽  
Nordihydroguaiaretic Acid ◽  
C6 Glioma ◽  
Cyclooxygenase Inhibitors ◽  
C6 Glioma Cells ◽  
C6 Cells ◽  
Lipoxygenase Inhibitor ◽  
Glioma C6

Among the brain tumors, glioma is the most common. In general, different biochemical mechanisms, involving nicotinic acetylcholine receptors (nAChRs) and the arachidonic acid cascade are involved in oncogenesis. Although the engagement of the latter in survival and proliferation of rat C6 glioma has been shown, there are practically no data about the presence and the role of nAChRs in C6 cells. In this work we studied the effects of nAChR antagonists, marine snail α-conotoxins and snake α-cobratoxin, on the survival and proliferation of C6 glioma cells. The effects of the lipoxygenase and cyclooxygenase inhibitors either alone or together with α-conotoxins and α-cobratoxin were studied in parallel. It was found that α-conotoxins and α-cobratoxin promoted the proliferation of C6 glioma cells, while nicotine had practically no effect at concentrations below 1 µL/mL. Nordihydroguaiaretic acid, a nonspecific lipoxygenase inhibitor, and baicalein, a 12-lipoxygenase inhibitor, exerted antiproliferative and cytotoxic effects on C6 cells. nAChR inhibitors weaken this effect after 24 h cultivation but produced no effects at longer times. Quantitative real-time polymerase chain reaction showed that mRNA for α4, α7, β2 and β4 subunits of nAChR were expressed in C6 glioma cells. This is the first indication for involvement of nAChRs in mechanisms of glioma cell proliferation.

Effect of Ligation of Left Pulmonary Artery at Birth on Maturation of Pulmonary Vascular Bed

Respiration ◽  
1962 ◽  
Vol 19 (5) ◽  
pp. 362-369
Author(s):  
Peter E. Pool ◽  
Keith H. Averill ◽  
John H.K. Vogel
Keyword(s):  
Pulmonary Artery ◽  
Left Pulmonary Artery ◽  
Vascular Bed ◽  
Pulmonary Vascular Bed
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