Neuroanatomical mapping of juvenile rat brain regions with prominent basal signal in [35S]GTPγS autoradiography

Aaltonen, Niina; Palomäki, Ville; Lecklin, Anne; Laitinen, Jarmo T.

doi:10.1016/j.jchemneu.2007.12.003

Cited by 9 publications

(12 citation statements)

References 40 publications

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“…35 S]GTPγS autoradiography was performed as previously described [26,28,34]. Briefly, the brain sections were processed in three sequential steps consisting of pre-incubation for 20/40 min (step 1), GDP-loading for 50/60 min (step 2), and 35 S]GTPγS labelling for 90 min (step 3).…”

Section: Methodsmentioning

confidence: 99%

“…Our previous studies have demonstrated that brain sections retain the capacity to generate endogenous GPCR agonists, such as adenosine and LPA, during incubation. This results in tonic adenosine A 1 and LPA receptor activity in anatomically defined brain regions and therefore serves as a convenient functional readout to monitor agonist activity at the two receptors [26-28]. The LPA-evoked 35 S]GTPγS binding response in rat brain sections reflects LPA 1 receptor activity, as it is sensitive to the LPA 1/3 -selective antagonist Ki16425 and is restricted to the developing white matter tracts [24,26,29].…”

Section: Introductionmentioning

confidence: 99%

“…This results in tonic adenosine A 1 and LPA receptor activity in anatomically defined brain regions and therefore serves as a convenient functional readout to monitor agonist activity at the two receptors [26-28]. The LPA-evoked 35 S]GTPγS binding response in rat brain sections reflects LPA 1 receptor activity, as it is sensitive to the LPA 1/3 -selective antagonist Ki16425 and is restricted to the developing white matter tracts [24,26,29]. This labelling pattern faithfully mirrors the known expression pattern of LPA 1 receptors in the developing rat brain [30-33].…”

Section: Introductionmentioning

confidence: 99%

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Lipid phosphate phosphatase inhibitors locally amplify lysophosphatidic acid LPA1 receptor signalling in rat brain cryosections without affecting global LPA degradation

et al. 2012

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BackgroundLysophosphatidic acid (LPA) is a signalling phospholipid with multiple biological functions, mainly mediated through specific G protein-coupled receptors. Aberrant LPA signalling is being increasingly implicated in the pathology of common human diseases, such as arteriosclerosis and cancer. The lifetime of the signalling pool of LPA is controlled by the equilibrium between synthesizing and degradative enzymatic activity. In the current study, we have characterized these enzymatic pathways in rat brain by pharmacologically manipulating the enzymatic machinery required for LPA degradation.ResultsIn rat brain cryosections, the lifetime of bioactive LPA was found to be controlled by Mg2+-independent, N-ethylmaleimide-insensitive phosphatase activity, attributed to lipid phosphate phosphatases (LPPs). Pharmacological inhibition of this LPP activity amplified LPA1 receptor signalling, as revealed using functional autoradiography. Although two LPP inhibitors, sodium orthovanadate and propranolol, locally amplified receptor responses, they did not affect global brain LPA phosphatase activity (also attributed to Mg2+-independent, N-ethylmaleimide-insensitive phosphatases), as confirmed by Pi determination and by LC/MS/MS. Interestingly, the phosphate analog, aluminium fluoride (AlFx-) not only irreversibly inhibited LPP activity thereby potentiating LPA1 receptor responses, but also totally prevented LPA degradation, however this latter effect was not essential in order to observe AlFx--dependent potentiation of receptor signalling.ConclusionsWe conclude that vanadate- and propranolol-sensitive LPP activity locally guards the signalling pool of LPA whereas the majority of brain LPA phosphatase activity is attributed to LPP-like enzymatic activity which, like LPP activity, is sensitive to AlFx- but resistant to the LPP inhibitors, vanadate and propranolol.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Lipid phosphate phosphatase inhibitors locally amplify lysophosphatidic acid LPA1 receptor signalling in rat brain cryosections without affecting global LPA degradation

et al. 2012

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“…The experiments did not involve any in vivo treatment. The sections were prepared as previously described [32]. Briefly, the rats were decapitated and within the next 5 min, the whole brain was dissected out, dipped briefly in isopentane (chilled on dry ice) and stored at −80 • C. Horizontal sections (20 m thick) were cut at −20 • C using a Leica cryostat, thaw-mounted onto Superfrost ® Plus slides (Menzel-Gläser, Germany), dried and stored thereafter at −80 • C.…”

Section: Brain Tissue Samplesmentioning

confidence: 99%

“…The method was validated and proved to be highly selective, accurate and precise. The method was applied to determine the differences in LPA contents of chemical pre-treated rat brain cryosections under conditions closely mimicking those of functional autoradiography where the neuroanatomical localization of LPA receptor signaling can be studied [30][31][32]. In this paper, we report preliminary results of brain sections to depict the endogenous content of LPA species in rat brain.…”

Section: Introductionmentioning

confidence: 99%