The effects of platelet-activating factor on the output of prostaglandins from the guinea-pig uterus

Norman, S.J.; Poyser, N.L.

doi:10.1016/0952-3278(92)90199-s

Cited by 7 publications

(6 citation statements)

References 15 publications

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“…The PAF-induced increase of CBF in primary cultures of epithelial ciliated cells from the hamster oviduct and the underlying mechanisms involved in this process were studied. It has been shown that PAF induces Ca 2+ mobilization [30] and prostaglandin production in different tissues [19,25]; however, it is not clear how these effects are related to cell function. We found that the PAF effect involves Ca 2+ mobilization, and PGE 2 and AA production as part of a cascade of biochemical events, including PLA 2 and COX-2 activation in the control of ciliary activity.…”

Section: Discussionmentioning

confidence: 98%

“…Moreover, PGE 2 , PAF, and arachidonic acid derivatives modify the ciliary activity of several epithelia, such as the respiratory and hearing systems [8,22]. There is also evidence of synergistic effects between PAF and PGE 2 to mobilize intracellular Ca 2+ in the uterus [19]; however, it is unclear whether the PAF-mediated PGE 2 production and Ca 2+ mobilization modify ciliated cell function.…”

Section: Introductionmentioning

confidence: 98%

“…In human endometrium and guinea pig uterus, PAF-induced PGE 2 production is coupled to intracellular Ca 2+ release [19]. Moreover, PGE 2 , PAF, and arachidonic acid derivatives modify the ciliary activity of several epithelia, such as the respiratory and hearing systems [8,22].…”

Section: Introductionmentioning

confidence: 99%

“…The intracellular mechanisms that mediate the effect of PAF in several cell types involve Ca 2+ mobilization [5], inositol 1,4,5-trisphosphate (IP 3 ) production, and prostaglandin synthesis [19,25]. In human endometrium and guinea pig uterus, PAF-induced PGE 2 production is coupled to intracellular Ca 2+ release [19].…”

Section: Introductionmentioning

confidence: 99%

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Platelet activating factor increases ciliary activity in the hamster oviduct through epithelial production of prostaglandin E2

Hermoso

Barrera

Morales

et al. 2001

Pflügers Arch - Eur J Physiol

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We investigated the signal transduction mechanisms associated with an increase in ciliary beat frequency (CBF) produced by platelet activating factor (PAF) in oviductal ciliated cell cultures. In the range of concentrations similar to that produced by preimplantation embryos, PAF increased the CBF in a dose-dependent manner. The addition of PAF and prostaglandin E2 (PGE2) to the cultures produced a synergic increase of ciliary beating, suggesting that PAF and PGE2 signal transduction pathways may be associated. To demonstrate this hypothesis, cyclooxygenase-2 (COX-2) was selectively blocked by a specific inhibitor, NS-398, and the PAF-induced CBF increase was abolished. Moreover, a phospholipase A2 (PLA2) inhibitor, AACOCF3, blocks the PAF-induced CBF increase. PGE2 production by oviductal epithelial cells is stimulated by PAF, and WEB-2086, a PAF-receptor blocker, specifically blocks the PAF-induced PGE2 production. Using the fluorescent indicator fura-2, we measured the effect of PAF on intracellular Ca2+ concentration ([Ca2+]i) in individual ciliated cells. PAF induced a transient increase of [Ca2+]i that was blocked by WEB-2086 or by removal of extracellular Ca2+. We propose a mechanism for PAF-mediated signal transduction in the ciliated cells of the oviductal epithelium. Minimal doses of PAF trigger Ca2+ mobilization in tandem with increased PLA2 activity and a COX-2-mediated increase in PGE2. Local PGE2 production by the oviductal mucosa suggests the presence of an autocrine loop controlling ciliary activity.

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Section: Discussionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Platelet activating factor increases ciliary activity in the hamster oviduct through epithelial production of prostaglandin E2

Hermoso

Barrera

Morales

et al. 2001

Pflügers Arch - Eur J Physiol

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“…For ovine endometrial cells in primary culture, PAF caused a dose-dependent increase in the release of PGE into medium but had no effect on PGF,, [11]. In the guinea pig, PAF significantly increased the output of PGF 2 ,, and PGE in the late luteal phase in vitro [12], and this depended upon mobilization of intracellular calcium. In vitro, PAF was found to be capable of generating inositol polyphosphate secondary messengers in ovine [13] and human endometrial tissue [14]; this implied its activation of phospholipase C. PAF also stimulated phosphatidylcholine phospholipase D in human endometrium in vitro [15].…”

Section: Introductionmentioning

confidence: 97%

Ovine Endometrium Synthesizes and Releases Platelet-Activating Factor, Which Can Cause the Release of Prostaglandin F2α by the Uterus in Situ1

Battye

Evans

O’Neill

1996

Biology of Reproduction

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Explanted endometrial tissue from ovariectomized ewes that had received hormone replacement to mimic the luteal phase released platelet-activating factor (PAF) into medium in vitro. On Day 14, 310.1 (261-2185), and on Day 15, 424.4 (14.1-590.7) pg PAF (median 25th-75th percentile; p > 0.05) was released per 100 mg endometrial tissue after a 20-min incubation. A regulatory and final enzyme in the PAF biosynthetic pathway, lysoPAF:acetyltransferase, was also present with a specific activity of 0.533 +/- 0.124 pmol acetate/50 micrograms protein/30 min in Day 14 endometrial tissue and 0.810 +/- 0.468 in Day 15 tissue (mean +/- SEM; p > 0.05). PAF:acetylhydrolase, the metabolic enzyme regulating PAF's half-life, was present in uterine luminal washings, with a specific activity of 3.78 +/- 1.37 nmol acetate released/min/mg protein on Day 14 and 3.41 +/- 0.34 on Day 15 (mean +/- SEM; p > 0.05). Intrauterine infusion of 50-400 micrograms PAF caused a dose-dependent release of prostaglandin (PG) F2 alpha (measured as venous 14-dihydro-15-keto-prostaglandin F2 alpha, PGFM) within 10 min on Days 13-15. The enantiomeric form of PAF was significantly less effective in inducing a rise in venous PGFM. WEB 2086 is reported to be a competitive receptor antagonist for PAF, but a 10-fold excess of WEB 2086 failed to inhibit PAF-induced release of PGFM. It was observed that this dose of WEB alone induced PGFM release, suggesting that in this model this agent may not work as a true competitive antagonist. Repeat challenges at intervals of 0, 90, and 120 min with either 200 micrograms PAF or micrograms oxytocin resulted in a marked tachyphylaxis of response by the third challenge. This desensitization after repeated PAF challenge suggests a specificity of its actions. Infusion of 200 micrograms PAF on Day 14 or 15 at five 60-min intervals resulted in a tachyphylaxis such that by the fourth and fifth challenges, essentially no response was observed. The tachyphylaxis that was induced by four repeat challenges with PAF had no apparent effect on the capacity of the uterus to respond to a fifth challenge with oxytocin. Thus, PAF and oxytocin both caused homologous desensitization of their own capacity to mobilize uterine PGF2 alpha, but PAF did not cause heterologous desensitization of the response to oxytocin. This failure of heterologous desensitization suggests differences in the mechanism of action of the two ligands. Kinetic binding studies showed that PAF did not compete for the oxytocin receptor in vitro. This result demonstrated that the ovine endometrium produces PAF and responds to it by the release of PGF2 alpha in situ. The dynamics of the response elicited by PAF were similar to those of oxytocin, yet the two mediators apparently act separately. PAF may be a modulator of PGF2 alpha release by the ovine uterus during the luteal phase.

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The control of prostaglandin production by the endometrium in relation to luteolysis and menstruation

Poyser

1995

Prostaglandins, Leukotrienes and Essential Fatty Acids

147

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The effects of platelet-activating factor on the output of prostaglandins from the guinea-pig uterus

Cited by 7 publications

References 15 publications

Platelet activating factor increases ciliary activity in the hamster oviduct through epithelial production of prostaglandin E2

Platelet activating factor increases ciliary activity in the hamster oviduct through epithelial production of prostaglandin E2

Ovine Endometrium Synthesizes and Releases Platelet-Activating Factor, Which Can Cause the Release of Prostaglandin F2α by the Uterus in Situ1

The control of prostaglandin production by the endometrium in relation to luteolysis and menstruation

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