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Distinct changes in cAMP and extracellular signal-regulated protein kinase signalling in L-DOPA-induced dyskinesia.

Santini E, Sgambato-Faure V, Li Q, Savasta M, Dovero S, Fisone G, Bezard E - PLoS ONE (2010)

Bottom Line: We here studied, in the gold-standard non-human primate model of Parkinson's disease, the changes in PKA-dependent phosphorylation of DARPP-32 and GluR1 AMPA receptor, as well as in ERK and ribosomal protein S6 (S6) phosphorylation, associated to acute and chronic administration of L-DOPA.In contrast, phosphorylation of ERK and S6 was enhanced preferentially after acute L-DOPA administration and decreased during the course of chronic treatment.Dysregulation of cAMP signalling is maintained during the course of chronic L-DOPA administration, while abnormal ERK signalling peaks during the initial phase of L-DOPA treatment and decreases following prolonged exposure.

View Article: PubMed Central - PubMed

Affiliation: Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.

ABSTRACT

Background: In rodents, the development of dyskinesia produced by L-DOPA in the dopamine-depleted striatum occurs in response to increased dopamine D1 receptor-mediated activation of the cAMP - protein kinase A and of the Ras-extracellular signal-regulated kinase (ERK) signalling pathways. However, very little is known, in non-human primates, about the regulation of these signalling cascades and their association with the induction, manifestation and/or maintenance of dyskinesia.

Methodology/results: We here studied, in the gold-standard non-human primate model of Parkinson's disease, the changes in PKA-dependent phosphorylation of DARPP-32 and GluR1 AMPA receptor, as well as in ERK and ribosomal protein S6 (S6) phosphorylation, associated to acute and chronic administration of L-DOPA. Increased phosphorylation of DARPP-32 and GluR1 was observed in both L-DOPA first-ever exposed and chronically-treated dyskinetic parkinsonian monkeys. In contrast, phosphorylation of ERK and S6 was enhanced preferentially after acute L-DOPA administration and decreased during the course of chronic treatment.

Conclusion: Dysregulation of cAMP signalling is maintained during the course of chronic L-DOPA administration, while abnormal ERK signalling peaks during the initial phase of L-DOPA treatment and decreases following prolonged exposure. While cAMP signalling enhancement is associated with dyskinesia, abnormal ERK signalling is associated with priming.

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Western blot analysis of levels of (A) phosphorylated DARPP-32 at Thr34, (B) phosphorylated GluR1 at Ser845, (C) phosphorylated ERK1/2 at Thr202/Tyr204 and (D) phosphorylated S6 at Ser235/Ser236 in the dorsal putamen (mean ± S.E.M.).Groups were prepared as depicted in figure 1. Representative blots are shown above each panel. Data were analysed using a one-way ANOVA followed by post hoc Tukey-Kramer multiple comparisons test (Graphpad Instat, Graphpad softwares, San Diego, CA). A probability level of 5% (*: P<0.05) was considered statistically significant. (A) F(6,37) = 3.6, P = 0.008; (B) F(6,42) = 3.4, P = 0.008; (C) F(6,38) = 3.9, P = 0.004; (D) F(6,38) = 3.9, P = 0.004.
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pone-0012322-g002: Western blot analysis of levels of (A) phosphorylated DARPP-32 at Thr34, (B) phosphorylated GluR1 at Ser845, (C) phosphorylated ERK1/2 at Thr202/Tyr204 and (D) phosphorylated S6 at Ser235/Ser236 in the dorsal putamen (mean ± S.E.M.).Groups were prepared as depicted in figure 1. Representative blots are shown above each panel. Data were analysed using a one-way ANOVA followed by post hoc Tukey-Kramer multiple comparisons test (Graphpad Instat, Graphpad softwares, San Diego, CA). A probability level of 5% (*: P<0.05) was considered statistically significant. (A) F(6,37) = 3.6, P = 0.008; (B) F(6,42) = 3.4, P = 0.008; (C) F(6,38) = 3.9, P = 0.004; (D) F(6,38) = 3.9, P = 0.004.

Mentions: Administration of L-DOPA, or MPTP-induced lesion, did not alter, per se, the phosphorylation of DARPP-32 at Thr34 (Fig. 2A), nor did they affect the phosphorylation of another PKA target, the GluR1 subunit of the glutamate AMPA receptor (Fig. 2B). In contrast, the first ever administration of L-DOPA to MPTP-lesioned monkeys induced a trend toward increased phosphorylation of DARPP-32 at Thr34, and a significant increase in phosphorylation of GluR1 at Ser845 (Fig. 2A–B). Following chronic treatment with L-DOPA, the phosphorylation of DARPP-32 at Thr34 and of GluR1 at the PKA site, Ser845 [16], was dramatically increased in MPTP dyskinetic monkeys (Fig. 2A–B). Enhanced DARPP-32 and GluR1 phosphorylation was also detected in non-dyskinetic animals. However, these increases did not reach statistical significance (Fig. 2A–B). Total levels of DARPP-32 and GluR1 were unaffected by MPTP lesion and/or treatment with L-DOPA (Fig. 2A–B). Thus, dopamine depletion is accompanied by a considerable increase in dopamine D1 receptor responsiveness at the postsynaptic level. This supports the idea of a correlation between persistent activation of PKA signalling and severity of LID.


Distinct changes in cAMP and extracellular signal-regulated protein kinase signalling in L-DOPA-induced dyskinesia.

Santini E, Sgambato-Faure V, Li Q, Savasta M, Dovero S, Fisone G, Bezard E - PLoS ONE (2010)

Western blot analysis of levels of (A) phosphorylated DARPP-32 at Thr34, (B) phosphorylated GluR1 at Ser845, (C) phosphorylated ERK1/2 at Thr202/Tyr204 and (D) phosphorylated S6 at Ser235/Ser236 in the dorsal putamen (mean ± S.E.M.).Groups were prepared as depicted in figure 1. Representative blots are shown above each panel. Data were analysed using a one-way ANOVA followed by post hoc Tukey-Kramer multiple comparisons test (Graphpad Instat, Graphpad softwares, San Diego, CA). A probability level of 5% (*: P<0.05) was considered statistically significant. (A) F(6,37) = 3.6, P = 0.008; (B) F(6,42) = 3.4, P = 0.008; (C) F(6,38) = 3.9, P = 0.004; (D) F(6,38) = 3.9, P = 0.004.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2925943&req=5

pone-0012322-g002: Western blot analysis of levels of (A) phosphorylated DARPP-32 at Thr34, (B) phosphorylated GluR1 at Ser845, (C) phosphorylated ERK1/2 at Thr202/Tyr204 and (D) phosphorylated S6 at Ser235/Ser236 in the dorsal putamen (mean ± S.E.M.).Groups were prepared as depicted in figure 1. Representative blots are shown above each panel. Data were analysed using a one-way ANOVA followed by post hoc Tukey-Kramer multiple comparisons test (Graphpad Instat, Graphpad softwares, San Diego, CA). A probability level of 5% (*: P<0.05) was considered statistically significant. (A) F(6,37) = 3.6, P = 0.008; (B) F(6,42) = 3.4, P = 0.008; (C) F(6,38) = 3.9, P = 0.004; (D) F(6,38) = 3.9, P = 0.004.
Mentions: Administration of L-DOPA, or MPTP-induced lesion, did not alter, per se, the phosphorylation of DARPP-32 at Thr34 (Fig. 2A), nor did they affect the phosphorylation of another PKA target, the GluR1 subunit of the glutamate AMPA receptor (Fig. 2B). In contrast, the first ever administration of L-DOPA to MPTP-lesioned monkeys induced a trend toward increased phosphorylation of DARPP-32 at Thr34, and a significant increase in phosphorylation of GluR1 at Ser845 (Fig. 2A–B). Following chronic treatment with L-DOPA, the phosphorylation of DARPP-32 at Thr34 and of GluR1 at the PKA site, Ser845 [16], was dramatically increased in MPTP dyskinetic monkeys (Fig. 2A–B). Enhanced DARPP-32 and GluR1 phosphorylation was also detected in non-dyskinetic animals. However, these increases did not reach statistical significance (Fig. 2A–B). Total levels of DARPP-32 and GluR1 were unaffected by MPTP lesion and/or treatment with L-DOPA (Fig. 2A–B). Thus, dopamine depletion is accompanied by a considerable increase in dopamine D1 receptor responsiveness at the postsynaptic level. This supports the idea of a correlation between persistent activation of PKA signalling and severity of LID.

Bottom Line: We here studied, in the gold-standard non-human primate model of Parkinson's disease, the changes in PKA-dependent phosphorylation of DARPP-32 and GluR1 AMPA receptor, as well as in ERK and ribosomal protein S6 (S6) phosphorylation, associated to acute and chronic administration of L-DOPA.In contrast, phosphorylation of ERK and S6 was enhanced preferentially after acute L-DOPA administration and decreased during the course of chronic treatment.Dysregulation of cAMP signalling is maintained during the course of chronic L-DOPA administration, while abnormal ERK signalling peaks during the initial phase of L-DOPA treatment and decreases following prolonged exposure.

View Article: PubMed Central - PubMed

Affiliation: Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.

ABSTRACT

Background: In rodents, the development of dyskinesia produced by L-DOPA in the dopamine-depleted striatum occurs in response to increased dopamine D1 receptor-mediated activation of the cAMP - protein kinase A and of the Ras-extracellular signal-regulated kinase (ERK) signalling pathways. However, very little is known, in non-human primates, about the regulation of these signalling cascades and their association with the induction, manifestation and/or maintenance of dyskinesia.

Methodology/results: We here studied, in the gold-standard non-human primate model of Parkinson's disease, the changes in PKA-dependent phosphorylation of DARPP-32 and GluR1 AMPA receptor, as well as in ERK and ribosomal protein S6 (S6) phosphorylation, associated to acute and chronic administration of L-DOPA. Increased phosphorylation of DARPP-32 and GluR1 was observed in both L-DOPA first-ever exposed and chronically-treated dyskinetic parkinsonian monkeys. In contrast, phosphorylation of ERK and S6 was enhanced preferentially after acute L-DOPA administration and decreased during the course of chronic treatment.

Conclusion: Dysregulation of cAMP signalling is maintained during the course of chronic L-DOPA administration, while abnormal ERK signalling peaks during the initial phase of L-DOPA treatment and decreases following prolonged exposure. While cAMP signalling enhancement is associated with dyskinesia, abnormal ERK signalling is associated with priming.

Show MeSH
Related in: MedlinePlus