Differential potentiation of arachidonic acid release by rat α2 adrenergic receptor subtypes

Audubert, François; Klapisz, Elsa; Berguerand, Marie; Gouache, P.; Jouniaux, Anne-Marie; Béréziat, G.; Masliah, J.

doi:10.1016/s1388-1981(99)00018-9

Cited by 13 publications

(16 citation statements)

References 38 publications

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“…2A). Treatment of cells with epinephrine and/or calcium ionophore A23187 caused a significant release of [ 3 H]D 4 Ach from prelabeled cells [24]. However, stimulation with these agonists produced no detectable translocation of endogenous cPLA 2 from cytosol to membranes in agreement with a recent report [33].…”

Section: R E S U L T Ssupporting

confidence: 92%

“…We have previously shown that stimulation of the a 2B adrenergic receptor in CHO-2B cells with epinephrine produces a small but significant increase in D 4 Ach release [24]. The maximal stimulation of D 4 Ach release was obtained by stimulating the cells with 1 mm epinephrine plus the calcium ionophore A23187, which potentiates the stimulation induced Fig.…”

Section: R E S U L T Smentioning

confidence: 79%

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N‐terminal and C‐terminal plasma membrane anchoring modulate differently agonist‐induced activation of cytosolic phospholipase A₂

Klapisz

Ziari

Wendum

et al. 1999

European Journal of Biochemistry

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The 85 kDa cytosolic phospholipase A 2 (cPLA 2 ) plays a key role in liberating arachidonic acid from the sn-2 position of membrane phospholipids. When activated by extracellular stimuli, cPLA 2 undergoes calciumdependent translocation from cytosol to membrane sites which are still a matter of debate. In order to evaluate the effect of plasma membrane association on cPLA 2 activation, we constructed chimeras of cPLA 2 constitutively targeted to the plasma membrane by the N-terminal targeting sequence of the protein tyrosine kinase Lck (Lck-cPLA 2 ) or the C-terminal targeting signal of K-Ras4B (cPLA 2 -Ras). Constitutive expression of these chimeras in Chinese hamster ovary cells overproducing the a 2B adrenergic receptor (CHO-2B cells) did not affect the basal release of [ 3 H]arachidonic acid, indicating that constitutive association of cPLA 2 with cellular membranes did not ensure the hydrolysis of membrane phospholipids. However, Lck-cPLA 2 increased [ 3 H]arachidonic acid release in response to receptor stimulation and to increased intracellular calcium, whereas cPLA 2 -Ras inhibited it, compared with parental CHO-2B cells and CHO-2B cells producing comparable amounts of recombinant wild-type cPLA 2 . The lack of stimulation of cPLA 2 -Ras was not due to a decreased enzymatic activity as measured using an exogenous substrate, or to a decreased phosphorylation of the protein. These results show that the plasma membrane is a suitable site for cPLA2 activation when orientated correctly.

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Section: R E S U L T Ssupporting

confidence: 92%

Section: R E S U L T Smentioning

confidence: 79%

N‐terminal and C‐terminal plasma membrane anchoring modulate differently agonist‐induced activation of cytosolic phospholipase A₂

Klapisz

Ziari

Wendum

et al. 1999

European Journal of Biochemistry

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“…However, Jones et al (1991) suggested that in CHO cells that this e ect was not altered by the PLA 2 inhibitor, quinacrine, and that further, the activation of PLA 2 in these cells was blocked by PTX. The latter observations have recently been con®rmed by Audubert et al (1999). Thus, to examine whether PLA 2 activation could underlie any of the agonist-mediated increases in cyclic AMP levels reported in the present investigation, we have assessed the ability of both (7)noradrenaline and (+)-meta-octopamine to activate PLA 2 activity by measuring the agonist-induced release of arachidonic acid from each of the three CHO cell lines expressing the a 2 -adrenoceptor subtypes at low expression levels.…”

Section: Does Increased Cyclic Amp Accumulation Involve the Activatiomentioning

confidence: 79%

“…See Kukkonen et al, 1998;Peltonen et al, 1998;Pihlavisto et al, 1998;Audubert et al, 1999;Olli-LaÈ hdesmaÈ ki et al, 1999;Prezeau et al, 1999;Takesono et al, 1999). The ability of the three a 2 -adrenoceptor subtypes to regulate the cyclic AMP second messenger pathway, has been extensively studied in numerous cell lines (Duzic & Lanier, 1992;Eason et al, 1992;Jansson et al, 1994b;NaÈ sman et al, 1997;Pohjanoksa et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

A comparison of agonist‐specific coupling of cloned human α₂‐adrenoceptor subtypes

Rudling

Richardson

Evans

2000

British J Pharmacology

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1 The agonist-speci®c coupling properties of the three cloned human a 2 -adrenoceptor subtypes have been compared, when expressed at similar levels in Chinese hamster ovary (CHO) cell lines, using noradrenaline and (+)-meta-octopamine as agonists. 2 Noradrenaline can couple the receptor to both the inhibition and stimulation of forskolinstimulated cyclic AMP production in all three receptor subtypes, with the relative strength of the coupling to the pathways varying for each of the receptor subtypes. 3 meta-Octopamine selectively couples the a 2A -adrenoceptor only to the inhibition of forskolinstimulated cyclic AMP production. However, meta-octopamine couples the a 2B -and a 2C -adrenoceptors to both the inhibition and stimulation of forskolin-stimulated cyclic AMP production. 4 The relative potency of meta-octopamine to noradrenaline varies between the di erent a 2 -adrenoceptor subtypes. The e ects of meta-octopamine are around two orders of magnitude less potent than those of noradrenaline on both the a 2A -and a 2B -adrenoceptor subtypes. In contrast, in the case of the a 2C -adrenoceptor, meta-octopamine is only one order of magnitude less potent than noradrenaline in the stimulation of forskolin-stimulated cyclic AMP production and, in addition, is equipotent with noradrenaline in the inhibition of forskolin-stimulated cyclic AMP production and has an increased maximal response. This raises the possibility that meta-octopamine may have physiologically important actions via a 2C -adrenoceptors in vivo. 5 The results show that the modulation of cyclic AMP production occurs in both a subtype-and agonist-speci®c manner for a 2A -adrenoceptors and in a subtype speci®c manner for a 2B -and a 2C -adrenoceptors.

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“…AA and its products play an important role in synaptic transmission, functional hyperemia, blood flow regulation (reviewed in: [7,31,38]). Additionally, several G proteins-coupled neurotransmitter receptors, including dopaminergic D2 [50], adrenergic α2 [1], and serotoninergic 2A/2C [4], can promote AA release from membrane phospholipids. Data suggest that COX-2 may also be required for brain muscarinic signaling.…”

Section: Discussionmentioning

confidence: 99%

Regional protein levels of cytosolic phospholipase A2 and cyclooxygenase-2 in Rhesus monkey brain as a function of age

Weerasinghe

Coon

Bhattacharjee

et al. 2006

Brain Research Bulletin

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Limited evidence suggests that brain cytosolic phospholipase A 2 (cPLA 2 ), which selectively releases arachidonic acid (AA) from membrane phospholipids, and cyclooxygenase-2 (COX-2), the ratelimiting enzyme for AA metabolism to prostanoids, change as a function of normal aging. In this study, we examined the protein levels of cPLA 2 and COX-2 enzymes in hippocampus, frontal pole and cerebellum from young (2-5 year-old), middle-aged (8-11 year-old) and old (23 year-old) male and female Rhesus monkeys. In the cerebellum, cPLA 2 protein level was higher in the young brain as compared to levels seen at both middle-aged and old. Similarly, in the frontal pole, the young brain showed a higher level of COX-2 protein as compared to the levels seen at both older ages. For both, once an animal reached 8-11 years of age the levels appeared to remain relatively constant over the next decade. Immunohistochemistry of COX-2 protein within the brain demonstrated no significant change in the localization to neurons within the frontal pole. In the young brain, the distribution of a low level of COX-2 protein within numerous neurons was different than the decreased number of neurons stained at a greater intensity in the adult brain. Based on the previous reports of localization of cPLA 2 and COX-2 at post-synaptic sites in neurons results from the current study suggest that the elevated protein levels of the two enzymes seen in the younger brain is related to the greater potential for synaptic plasticity across multiple neurons as a function of age and that cPLA 2 and COX-2 may be considered as post-synaptic markers.

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Differential potentiation of arachidonic acid release by rat α2 adrenergic receptor subtypes

Cited by 13 publications

References 38 publications

N‐terminal and C‐terminal plasma membrane anchoring modulate differently agonist‐induced activation of cytosolic phospholipase A₂

N‐terminal and C‐terminal plasma membrane anchoring modulate differently agonist‐induced activation of cytosolic phospholipase A₂

A comparison of agonist‐specific coupling of cloned human α₂‐adrenoceptor subtypes

Regional protein levels of cytosolic phospholipase A2 and cyclooxygenase-2 in Rhesus monkey brain as a function of age

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Differential potentiation of arachidonic acid release by rat α2 adrenergic receptor subtypes

Cited by 13 publications

References 38 publications

N‐terminal and C‐terminal plasma membrane anchoring modulate differently agonist‐induced activation of cytosolic phospholipase A2

N‐terminal and C‐terminal plasma membrane anchoring modulate differently agonist‐induced activation of cytosolic phospholipase A2

A comparison of agonist‐specific coupling of cloned human α2‐adrenoceptor subtypes

Regional protein levels of cytosolic phospholipase A2 and cyclooxygenase-2 in Rhesus monkey brain as a function of age

Contact Info

Product

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N‐terminal and C‐terminal plasma membrane anchoring modulate differently agonist‐induced activation of cytosolic phospholipase A₂

N‐terminal and C‐terminal plasma membrane anchoring modulate differently agonist‐induced activation of cytosolic phospholipase A₂

A comparison of agonist‐specific coupling of cloned human α₂‐adrenoceptor subtypes