Copyright © 2004 by Institute of Pharmacology Polish Journal of Pharmacology Polish Academy of Sciences Pol. J. Pharmacol., 2004, 56, 647–650 ISSN 1230-6002

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INFLUENCE OF THE THERAPY WITH PERGOLIDE MESYLATE PLUS L-DOPA AND WITH L-DOPA ALONE ON SERUM cGMP LEVEL IN PD PATIENTS

Ma³gorzata Chalimoniuk1,#, Adam Stêpieñ2 Department of Cellular Signaling, Medical Research Centre, Polish Academy of Sciences, Pawiñskiego 5, PL 02-106 Warszawa, Department of Neurology, Aviation Institute of Medicine, Krasiñskiego 54, PL 02-755 Warszawa, Poland

Influence of the therapy with pergolide mesylate plus L-DOPA and with L-DOPA alone on serum cGMP level in PD patients. M. CHALIMONIUK, A. STÊPIEÑ. Pol. J. Pharmacol., 2004, 56, 647–650. The aim of our study was to investigate serum cGMP level in patients treated with L-DOPA alone and L-DOPA with pergolide mesylate (PM) and to compare the obtained values with age-matched healthy subjects. PD patients treated with L-DOPA or with PM + L-DOPA had significantly higher cGMP levels in serum as compared to control. Moreover, cGMP level was significantly higher after treatment with PM + L-DOPA then L-DOPA alone. We did not observed significant differences in UPDRS scores between both PD groups. Our data suggest that changes in serum cGMP level in PD patients are related with PM + L-DOPA or L-DOPA alone therapy. Key words: serum cGMP level, Parkinson’s disease, pergolide mesylate, L-DOPA

 correspondence; e-mail: [email protected] M. Chalimoniuk, A. Stêpieñ

Abbreviations: ANOVA – analysis of variance, L-DOPA has been used as a method of choice cGMP – guanosine 3’,5’-cyclic monophosphate, for PD treatment. However, application of this drug CSF – cerebrospinal fluid,GC–guanylyl cyclase, for years may lead to side effects. Thus, dopamine GTP – guanosine 5’-triphosphate, L-DOPA – levo- agonists were introduced into PD treatment to dopa,NO–nitric oxide, NOS – nitric oxide syn- avoid disadvantageous effect of L-DOPA therapy thase, ONOO – peroxynitrite,PD–Parkinson’s [4]. disease, PKG – cGMP-dependent protein kinase, The aim of this study was to investigate serum PM – pergolide mesylate, UPDRS – Unified Park- cGMP level in patients treated with L-DOPA alone inson’s Disease Rating Scale and L-DOPA with pergolide mesylate (PM) and to compare the obtained values with age-matched healthy subjects. Parkinson’s disease (PD) is characterized by a slow A total of 27 patients with idiopathic PD and 17 and progressive degeneration of the dopaminergic age-matched and healthy persons (the control neurons in the nigrostriatal system. Evidences from group) were recruited for the study. All subjects clinical and experimental studies support the in- provided the informed consent prior to their inclu- volvement of free radicals [nitric oxide (NO) and sion in the study. The informed consent was ob- reactive oxygen species] in the degeneration of the tained in compliance with the Declaration of Hel- dopaminergic neurons [9]. NO is the main activator sinki. Patients were diagnosed with idiopathic PD of guanylyl cyclase (GC), which catalyzes the con- according to explicit criteria based on the presence version of guanosine 5’-triphosphate (GTP) to of clinical symptoms (rest tremor, bradykinesia, ri- guanosine 3’5’-cyclic monophosphate (cGMP). gidity, and postural instability). The patients treated cGMP activates a protein kinase, modulating di- with L-DOPA (for a mean of 6 years, range: verse biochemical events through the phosphoryla- 1–8 years) were divided into two groups. One tion of protein [8]. In addition, the NO/cGMP path- group of 16 patients was followed further with way modulates striatal release of several neuro- L-DOPA therapy for additional two years, whereas transmitters, including dopamine and excitatory the other group of 11 patients was treated with amino acids. cGMP has been measured as possible L-DOPA plus PM for the same period of time. indicator of activity of GC. L-DOPA was administrated at a dose of 1000–1500 An increase in activity and expression of neu- mg daily; PM was given at a dose of 0.75–1.25 mg ronal nitric oxide synthase (NOS) and inducible daily. A standardized PD assessment tool termed NOS seen in PD leads to overproduction of NO and the Unified Parkinson’s Disease Rating Scale may be implicated in its diffusion throughout neu- (UPDRS part III motor score) was used to docu- ron’s lipid membranes [2]. This may enhance ment motor examination findings. Venous blood plasma level of cGMP by stimulation of soluble was obtained from fasted patients with PD and con- GC. The efflux of cyclic nucleotides from neurons trols between 8–10 a.m. Patients with PD were observed in the brain might also elevate plasma given the last dose of antiparkinsonian drugs at cGMP [3]. Moreover, the presence of cGMP in ex- 8 p.m. on the previous day. Blood was collected in tracellular fluids, including cerebrospinal fluid centrifuge tube without any additives. After 30 min, (CSF), plasma and urine, was considered to be a re- blood samples were centrifuged at 1500×gfor liable index of NO efflux and activity [3]. Navarro 15 min. Serum samples were stored at –70°C until et al. [5] did not find any changes in plasma cGMP used for analysis. level in PD patients as compared to control subjects cGMP level was determined using a commer- despite marked elevation of CSF cGMP level seen cially available ELISA kit (Amersham Pharmacia in PD. Previously, Volicer et al. [7] reported similar Biotech, Piscataway, NJ) according to the proce- CSF cGMP level in PD patients and controls. Bel- dure supplied by the manufacturer. The results of maker et al. [1] reported a significant reduction of experiments were evaluated by one-way analysis of CSF cGMP of PD patients compared with schizo- variance (ANOVA) followed by Newman-Keuls phrenic patients and no effect of L-DOPA on this post-hoc test. Statistical probability of p < 0.05 was value was found in both groups of patients. There considered significant. are no data whether these mechanisms operate with UPDRS rating scores were established directly regard to PD. before blood drawing. We did not observe signifi-

648 Pol. J. Pharmacol., 2004, 56, 647–650 INFLUENCE OF THERAPY WITH PM + L-DOPA AND L-DOPA ALONE ON SERUM cGMP IN PD

Table 1. Age and sex of control subjects and PD patients and results of UPDRS rating of PD patients Sex Age [years] UPDRS score [points]

Control 10 men and 7 women 58.2 ± 6.5 (range 54–5) L-DOPA 10 women and 6 men 66.4 ± 8.0 (range 58–72) 42 ± 18 (n = 16) PM-L-DOPA 7 women and 4 men 64.8 ± 7.1 (range 62–70) 38 ± 10 (n = 11)

PM – pergolide mesylate. Variables are expressed as the means ± SEM cant differences in UPDRS scores between both PD sion of GTP to cGMP, is the major physiological groups (Tab. 1). The results of UPDRS examina- receptor for NO in the central nervous system, as tion averaged 42 ± 18 points (n = 16) in L-DOPA- well as in blood vessels and peripheral organs [2]. treated group, and 38 ± 10 points (n = 11) in the It is worth noting that L-DOPA therapy can cause group treated with PM + L-DOPA (Tab. 1). a marked rise of cGMP level in the cerebellum and Serum cGMP concentration increased signifi- CSF [5]. In our study, cGMP was also markedly cantly in both groups PD of patients compared to elevated in serum of L-DOPA-treated patients in control group. However, PD patients treated with comparison to control and this effect was further PM + L-DOPA had significantly higher serum enhanced in PM + L-DOPA-treated patients (Fig. cGMP level than PD patients treated with L-DOPA 1). The combination therapy can prevent peroxyni- alone (Fig. 1). trite (ONOO`) formation, but dose not inhibit Among factors involved in free radical forma- cGMP production. This may reflect the fact that tion during PD are impairment of mitochondrial PM may act via dual control of oxidative stress due complex I function, increase in NO production and lipid peroxidation in the substantia nigra and stria- to its free radical scavenging and antioxidant pro- tum [9]. To elucidate a possible participation of NO perties as was shown in vitro by electron spin reso- in free radical formation, we determined serum nance technique [4]. However, previously per- cGMP concentration. Measurement of cGMP in ex- formed in vivo study indicates that neuroprotective tracelullar fluids was considered to be a reliable in- effect of PM may be largely attributed to activation dex of NO output in vivo [3]. It is well documented of presynaptic autoreceptors and the induction of that GC, the enzyme which catalyzes the conver- Cu/Zn superoxide dismutase by this drug. There is no data available concerning the direct effect of *# 2000 pergolide on cGMP formation. However, some in-

1800 direct information may be derived from the study with U-95666E, D selective agonist, that dose- 1600 dependently attenuated stress-induced elevation of

serum] 1400 f * mice cerebellar cGMP [6]. The common feature of 1200 two compounds is their high affinity for D recep- 1000 tors. Elevation of serum cGMP level may, at least 800 to some extent, reflect release of cGMP from brain 600 neurons [2]. However, it may be considered that

MP level [pmol/ml o 400 G elevated production of NO intensifies its diffusion c 200 into circulation and enhances cGMP formation ei- 0 ther in cellular elements of the blood or vascular control L-DOPA PM+L-DOPA endothelium. These observations suggest that Fig. 1. Effect of L-DOPA and PM + L-DOPA on concentration change in the serum cGMP level of PD patients are of cGMP in serum from PD patients. cGMP level was related with PM + L-DOPA. determined using a commercially available ELISA kit accord- ing to the procedure supplied by manufacturer. Each value is the mean ± SEM from 11–17 patients determined in triplicate. The statistical analysis was performed by one-way ANOVA using Acknowledgment. This work was supported by grant Newman-Keuls post-hoc test. * p < 0.05 compared to control no. 3P05A 136 22 from the State Committee for Scientific value,#p<0.05 compared to L-DOPA value Research, Warszawa, Poland.

ISSN 1230-6002 649 M. Chalimoniuk, A. Stêpieñ

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