PLATELET ACTIVATING FACTORS AND RELATED LIPIDS

PLATELET ACTIVATING FACTORS

Since its discovery over two decades ago¹, platelet activating factor (PAF) has emerged as one of the most important lipid mediators known. PAF or 1-O-alkyl-2-O-acetyl-sn-glycero-3-phosphorylcholine exists endogenously as a mixture of molecular species which are structural variants of the alkyl moiety, with the C-16 species predominating². PAF not only activates platelets but also basophils, endothelial cells, eosinophils, lymphocytes, macrophages, mast cells, monocytes, and neutrophils. These cells not only respond to PAF but produce and release it as well. PAF induces an impressive repertoire of physiologic responses including phagocytosis, exocytosis, superoxide production, chemotaxis, aggregation, proliferation, adhesion, eicosanoid generation, degranulation, calcium mobilization as well as diverse morphological changes. These responses are mediated via stereospecific G-protein coupled receptors^3,4. The pathophysiological effects of PAF in animals include bronchoconstriction, hypotension, neutropenia, thrombocytopenia and vascular permeability leading to impairment of cardiac and renal function, pulmonary edema, anaphylaxis⁵ and death⁶. Numerous reviews have been published on various aspects of PAF research including its role in allergic disease⁷, asthma⁸, ischemia⁹, endotoxin shock¹⁰, cellular responses¹¹, SAR¹², antagonists^13,14,15 and general reviews^16,17,18.

L-100
PAF C-16
1-O-Hexadecyl-2-O-acetyl-sn-glycero-3-phosphorylcholine
99%, MW=523.7 [74389-68-7] Storage: -20°C
5 mg
25 mg

L-134
1-Acyl-PAF
1-O-Palmitoyl-2-O-acetyl-sn-glycero-3-phosphorylcholine
99%, MW=537.7, Storage: -20°C
The predominant PAF species produced by stimulated endothelial cells^19,20.
1 mg
5 mg

L-110
Enantio-PAF C-16
3-O-Hexadecyl-2-O-acetyl-sn-glycero-1-phosphorylcholine
99%, MW=523.7 [117985-57-6] Storage: -20°C
A biologically inactive enantiomer of PAF²¹.
1 mg
5 mg

L-105
PAF C-18
1-O-Octadecyl-2-O-acetyl-sn-glycero-3-phosphorylcholine
99%, MW=551.8 [79549-26-1] Storage: -20°C
5 mg
25 mg

EI-150
1-O-Hexadecyl-2-O-acetyl-sn-glycerol
98%, MW=358.6 [77133-35-8] Storage: -20°C
Inhibits protein kinase C activation by diacylglycerols²². Stimulates HL-60 cell differentiation²³. Biosynthetic precursor of PAF via remodeling and retroconversion/de novo routes²⁴. Induces delayed aggregation of rabbit platelets²⁵. Mitogenic for smooth muscle cells²⁶.
5 mg
5 x 5 mg

L-101
Lyso-PAF C-16
1-O-Hexadecyl-sn-glycero-3-phosphorylcholine
99%, MW=481.7 [52691-62-0] Storage: -20°C
Biologically inactive PAF metabolite resulting from the action of PAF acetyl hydrolase²¹.
5 mg
25 mg

L-128
Lyso-PAF C-18
1-O-Octadecyl-sn-glycero-3-phosphorylcholine
99%, MW=481.7 [74430-89-0] Storage: -20°C
Biologically inactive PAF metabolite resulting from the action of PAF acetyl hydrolase²¹.
5 mg
25 mg

L-107
PAF C-18:1
1-O-Oleyl-2-O-acetyl-sn-glycero-3-phosphorylcholine
99%, MW=549.6 [85966-90-1] Storage: -20°C
5 mg
25 mg

L-102
1-O-Hexadecyl-2-O-arachidonoyl-sn-glycero-3-phosphorylcholine
98%, 5 mg/200 µl ethanol, MW=768.2 [86288-11-1] Storage: -20°C
A biosynthetic precursor of PAF via the lipid remodeling pathway²⁷.
5 mg
25 mg

L-115
1-O-Hexadecyl-2-O-eicosapentaenoyl-sn-glycero-3-phosphorylcholine
98%, 5 mg/200 µl ethanol, MW=766.2, Storage: -20°C
A biosynthetic precursor of PAF via the lipid remodeling pathway²⁴.
5 mg
25 mg

L-116
1-O-Hexadecyl-2-O-dihomo-g-linolenoyl-sn-glycero-3-phosphorylcholine
98%, 5 mg/200 µl ethanol, MW=770.2, Storage: -20°C
A biosynthetic precursor of PAF via the lipid remodeling pathway²⁴.
5 mg
25 mg

L-117
1-O-Hexadecyl-2-O-docosahexaenoyl-sn-glycero-3-phosphorylcholine
98%, 5 mg/200 µl ethanol, MW=792.2, Storage: -20°C
A biosynthetic precursor of PAF via the lipid remodeling pathway²⁴.
5 mg
25 mg

PAF AGONISTS

L-120
C-PAF
Carbamyl-PAF
1-O-Hexadecyl-2-N-methylcarbamyl-sn-glycero-3-phosphorylcholine
98%, MW=538.7 [91575-58-5] Storage: -20°C
Posesses full agonist activity approaching PAF in potency. Induces half-maximal PMNL degranulation response at 16nM and binds stereospecifically to high and low affinity PAF receptors. Completely resists inactivation by acetylhydrolase^28,29.
5 mg
25 mg

L-119
E-PAF
2-O-Ethyl-PAF
1-O-Hexadecyl-2-O-ethyl-sn-glycero-3-phosphorylcholine
98%, MW=509.7, Storage: -20°C
Degranulates human neutrophils (20-40 fold less active than PAF)³⁰. Desensitizes neutrophil PAF receptors²¹. Completely resists inactivation by acetylhydrolase³¹.
5 mg
25 mg

L-108
ET-18-OCH₃
1-O-Octadecyl-2-O-methyl-sn-glycero-3-phosphorylcholine
99%, MW=523.7 [77286-66-9] Storage: -20°C
Similar activity to 2-O-methyl PAF. Antineoplastic activity³². Inhibits phospholipase C³³.
5 mg
25 mg

L-106
2-O-Methyl PAF
(?1-O-Hexadecyl-2-O-methylglycero-3-phosphorylcholine
99%, MW=495.7, Storage: -20°C
Antineoplastic activity^17,34,35. Partial PAF agonist. Desensitizes neutrophil PAF receptors21.
5 mg
25 mg

PAF ANTAGONISTS

L-122
Bis(methylthio)gliotoxin (FR-49175)
99%, MW=356.5 [74149-38-5] Storage: -20°C
Inhibits PAF induced platelet aggregation (IC₅₀=8.4 µM) and collagen induced aggregation (IC₅₀=84.2 µM) with no effect on arachidonic acid or ADP induced aggregation³⁶. Inhibits PAF induced bronchoconstriction in vivo in the guinea-pig (69% at 1.0 mg/kg)³⁷.
1 mg
5 mg

L-123
(? trans-2,5-Bis(3,4,5-trimethoxyphenyl)-1,3-dioxolane
98%, MW=406.4 [116673-45-1] Storage: 0°C
A potent and selective PAF antagonist of the diaryl tetrahydrofuran class (K_i=0.3 µM, rabbit platelet assay)³⁸.
1 mg
5 mg

L-124
(? cis-2,5-Bis(3,4,5-trimethoxyphenyl)-1,3-dioxolane
98%, MW=406.4 [116673-47-3] Storage: 0°C
A biologically inactive isomer of L-123. May be used as a negative control³⁸.
1 mg
5 mg

L-103
CV-3988
98%, MW=592.8 [85703-73-7] Storage: -20°C
Competitive PAF receptor antagonist³⁹. Inhibits PAF induced human platelet aggregation (3-30 µM)³⁹ and bronchoconstriction in the guinea-pig⁴⁰. Inhibits PAF induced hypotension⁴⁰, contraction of isolated rat colon⁴¹, acute pancreatitis⁴², negative inotropic effects⁴³ and lethality⁴⁴. Prevents the effects of systemically administered endotoxin⁴⁵. An important standard for comparison with other PAF antagonists¹⁵.
5 mg
25 mg

L-136
CV-6209
97%, MW=642.3 [117064-08-1] Storage: -20°C
Competitive PAF receptor antagonist⁴⁶. Inhibits PAF induced human platelet aggregation (IC₅₀=0.17 µM)⁴⁶. Inhibits PAF induced hypotension and lethality⁴⁶. Reduces cardiac damage during myocardial ischemia⁴⁷.
1 mg
5 mg

L-135
Ginkgolide B (BN 52021)
90%, MW=424.4 [15291-77-7] Storage: -20°C
Most potent member of the ginkgolide family of PAF antagonists. Inhibits PAF induced platelet aggregation⁴⁸. Inhibits PAF induced PMNL chemotaxis (IC₅₀=490 nM)⁴⁹ and adhesion⁵⁰. Inhibits PAF induced Ca²⁺ mobilization in U937 cells (IC₅₀=340 nM)⁵¹. Orally effective against PAF induced bronchospasm⁵². Review⁵³.
10 mg
50 mg

L-125
1-O-Hexadecyl-2-O-acetyl-sn-glycero-3-phospho-(N,N,N-trimethyl) hexanolamine
98%, MW=579.8 [99103-16-9] Storage: -20°C
Inhibits PAF induced platelet aggregation, secretion and IP₃ production (IC₅₀=0.04 µM)⁵⁴. Inhibits release of active oxygen species from PAF activated human monocyte derived macrophages (IC₅₀=64 µM)⁵⁵. Completely inhibits PAF stimulated glycogenolysis and vasoconstriction in the perfused rat liver at 0.2 nM⁵⁶.
1 mg
5 mg

L-131
Octylonium bromide
98%, MW=563.6 [26095-59-0] Storage: 0°C
Binds to rabbit platelet PAF receptors with high affinity⁵⁷. Inhibits PAF induced platelet aggregation in rabbits (IC₅₀=7.7 µM), bronchoconstriction in guinea-pigs, hypotension in rats and lethality in mice. Inhibits endotoxin-induced gastrointestinal damage (known to be due to PAF). Does not inhibit PAF induced contraction of guinea pig lung parenchymal strips⁵⁸. Clinically useful spasmolytic agent for the control of increased tone or motility of the gut⁵⁹.
5 mg
25 mg

L-133
PCA-4248
Methyl 2-(phenylthio)ethyl-1,4-dihydro-2,4,6-trimethylpyridine-3,5-dicarboxylate
98%, MW=361.4, Storage: 0°C
Inhibits [³H]-PAF binding to human platelet and PMNL receptors (IC₅₀=1 µM) and PAF induced human platelet aggregation (IC₅₀=3.6 µM)⁶⁰.
10 mg
50 mg

L-126
Tetrahydrocannabinol-7-oic acid
11-Nor-D⁸-tetrahydrocannabinol-9-carboxylic acid
98%, MW=344.4 [39690-06-7] Storage: 0°C
A nonpsychoactive metabolite of tetrahydrocannabinol with potent bronchodilatory, antiinflammatory and analgesic activity^61,62. Prevents PAF induced mortality in mice and PAF induced mouse paw edema (ID₅₀=20 mg/kg)⁶³. Indirectly antagonizes the actions of PAF⁶⁴. Inhibits leukocyte adhesion⁶⁵.
1 mg
5 mg

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