Study Results
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Basic Information
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COMPLETED
NA
31 participants
INTERVENTIONAL
2011-09-30
2014-12-31
Brief Summary
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Other parameters will be recorded: biochemical (prolactin, GH) and neurophysiological (Spike-Waves Discharge: SWD rating). Safety parameters will be recorded to assess tolerance.
Detailed Description
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The primary objective is to assess dopaminergic reactivity using a behavioural marker (i.e. yawning) in patients with idiopathic generalized epilepsy compared to matched healthy controls after injection of either low dose of apomorphine or placebo. Other parameters will be recorded as secondary outcomes: behavioural (blinking), biochemical (prolactin, GH) and neurophysiological (Spike-Waves Discharge: SWD rating) markers. Safety parameters will be recorded to assess tolerance.
Experimental data: hyperdopaminergic response in a model of absence-epilepsy in the rat. Since the late 80's, our laboratory has demonstrated the existence of an endogenous neural mechanism that controls the occurrence of epileptic seizures in different animal models, a system based on the hypothesis that the basal ganglia modulate the synchronisation of epileptic rhythmic activities (Depaulis 1994). The studies performed in GAERS (Genetic Absence Epilepsy Rats from Strasbourg, a validated model of absence-epilepsy in rat) have shown that inhibition of the main output structure of basal ganglia (i.e., the substantia nigra pars reticulata) had antiepileptic effects (Depaulis 1994; Deransart 1996). Similarly, deep brain stimulation of the substantia nigra pars reticulata as well as of the subthalamic nucleus interrupts seizures (Vercueil 1998; Feddersen 2007). Systemic and intrastriatal dopamimetics injections in GAERS also suppress seizures, whereas antagonists worsen them (Warter et al, 1988; Deransart et al., 2000). Electrophysiological data showed respectively decreased and increased activity of DA neurons during and at the end of absence-seizures (Lücking et al. 2002). An increase in D3 receptor transcripts was also observed in adult GAERS as compared to inbred non epileptic control rats (NEC), within the ventral striatum (Deransart et al. 2001). These data suggest changes in the DA tone in GAERS with fully developed epileptic phenotype. According to the key role of DA D3 neurotransmission in the foetal cortical development (Levant B, 1995) and modulation of DA tone (Nissbrandt et al., 1995; Gilbert et al., 1995; Kreiss et al., 1995), the researchers investigated whether the putative impaired DA tone in GAERS correlates with functional changes in spontaneous and quinpirole-induced yawning behaviour (Kurashima et al. 1995; Collins et al.2005). The hypothesis of an increased dopaminergic tone in GAERS was thus addressed using pharmacology and microdialysis. In GAERS and NEC (i) spontaneous and quinpirole-induced yawning behaviour and (ii) changes in intra-accumbens dopamine contents induced by amphetamine and K+ and measured by microdialysis were investigated. Spontaneous yawning was significantly decreased in GAERS (0.3±0.2 yawn/hr, n=9) as compared to NEC (5.4±1.2, n=8) and Wistar Harlan rats (9.7±2.3, n=7). Quinpirole-induced yawning was significantly increased in GAERS (29.4±4.9) as compared to NEC (10.5±2.7) and Wistar-Harlan rats (22.6±3.5). Quinpirole also increased the number of absence-seizures in GAERS (+47.4±8.6%). When compared to NEC, basal levels of DA were 40% lower in GAERS whereas amphetamine and K+ produced a higher increase in extracellular dopamine in GAERS. The increased quinpirole-induced yawning in GAERS may account for an overexpression in D3 transcripts. The increased responsiveness of dopamine transmission observed in GAERS after pharmacological manipulations, as compared to NEC, suggests a " hyperdopaminergic " phenotype of GAERS. Altogether, these data support that GAERS have an impaired DA tone that may be associated with the development of mechanisms controlling absences seizures (Deransart et al, in preparation).
Altogether, these data suggest that a phasic involvement (" on request ") of the basal ganglia - notably under the influence of the dopaminergic neurotransmission - may underlie the rapid changes in extracellular activity recorded in output structures of the basal ganglia at the end of seizures in this model (Deransart 2003). Such a phasic functioning of the dopaminergic system in the control of seizures could also reconcile with the apparent discrepancy regarding the fact that seizures appear to escape chronic high-frequency stimulations of the substantia nigra (Feddersen 2007). These data strengthen the need for a re-appraisal of clinical approaches, especially based from a dynamic point of view regarding the involvement of the dopaminergic system in epilepsy.
Clinical data:
* Involvement of the dopaminergic system in idiopathic generalized epilepsies. Exposure to dopaminergic antagonists, like antipsychotic drugs, increases the risk for the patients to display epileptic seizures. The mechanism by which these treatments may lead to such an aggravation remains unknown and, up to date, there is no pharmacological strategy to decrease such a risk. Recent data suggested the involvement of the dopaminergic pathways in several epileptic syndromes: a significant homogeneous decrease in striatal dopamine uptake has been shown using PET in patients with epileptic seizures associated with ring chromosome 20 mosaicism (Biraben, 2004). In this epileptic syndrome, patients display prolonged seizures, reminiscent of an absence status epilepticus. A similar study, using a marker for the dopamine transporter, recently reported a decrease in dopamine re-uptake at the level of the substantia nigra in patients with idiopathic generalized epilepsies (Ciumas, 2008). These data differ from what is observed in neurodegenerative pathologies involving the dopaminergic system (e.g., Parkinson disease) where imaging studies of the dopaminergic transmission show a decrease in synaptic terminals linked to a progressive degenerative process. Data from epileptic patients rather suggest a modulation of the expression of some dopaminergic receptors as well as dynamic changes in the synaptic transmission. In line with our experimental data and the recently published neuroimaging studies, the investigators propose that the reactivity of the dopaminergic system displays special features specific to epileptic patients and may constitute a risk-level marker for epileptic seizures. The conceptual framework of the proposed translationnal study lies on the dynamic involvement of the dopaminergic system and the assessment of its reactivity in epileptic patients.
* Reactivity of the dopaminergic system in idiopathic generalized epilepsies. Low doses of apomorphine, a dopaminergic agonist, induce yawning and palpebral winking in healthy subjects (Blin, 1990). Similarly, higher therapeutic doses induce yawning immediately before therapeutic effect in patients with Parkinson's disease. These data suggest that higher affinity of apomorphine to presynaptic receptor could be involved in promoting yawning and blinking. The study of dopaminergic system response to low doses of apomorphine, below the side-effects threshold (nausea, vomiting, hypotension) represent an original, well-tolerated approach in both patients with epilepsy and healthy subjects. Similar studies have already been published in patients with migraine (Cerbo, 1997) and cocaine users (Colzato, 2008) in order to study dopaminergic reactivity in selected populations. The investigators propose to study dopaminergic reactivity in patients with idiopathic generalized epilepsy compared to matched healthy volunteers, during prolonged EEG after sleep-deprivation, using apomorphine doses of 1 µg/kg and 5 µg/kg. Indeed, apomorphine 0.5 to 2 µg/kg increased spontaneous blinking rate and yawning in healthy volunteers (Blin, 1990). However, a 10 µg/kg dose induced symptoms such as nausea, vomiting, sweating and dizziness in migraineurs (Cerbo, 1997). The study will focus on behaviour (spontaneous and apomorphine-induced yawning and blinking) and EEG (spontaneous and apomorphine induced SWD) as compared to placebo. Prolactin and GH dosing after apomorphine injection will provide a biochemical validation of dopaminergic stimulating effect. Indeed, prolactin secretion is inhibited by dopamine from the hypothalamus, while Growth hormone (GH) is stimulated. Thus, a decrease in prolactin and an increase in GH reflect central dopamine availability. Dosing prolactin and GH response to apomorphine subcutaneous injection represents a way to document the synaptic effects of the drug, as previously described (Aymard, 2003; Friess, 2001).
This project arises from concepts developed in our laboratory from experimental data obtained in an animal model of epilepsy and from recent clinical data from the literature. It aims at improving understanding of dopaminergic transmission dynamics in patients with epilepsy. It could therefore promote the emergence of new markers of susceptibility to epileptic seizures and constitute an opportunity to develop new pharmacological approaches based on dopaminergic neuromodulation.
Conditions
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Keywords
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Study Design
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RANDOMIZED
CROSSOVER
BASIC_SCIENCE
DOUBLE
Study Groups
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Apomorphine
After randomization healthy volunteers or patients with idiopathic generalized epilepsy receive:
-sequence A: 1 mg/kg and then 5 mg/kg of apomorphine
Apomorphine (Experimental product)
Dosage Form: Injection Dosage: 1 or 5 mg / kg
Route of administration: Subcutaneous
Duration of treatment: two injections of apomorphine followed by two injections of a placebo one week after or vice versa.
Two injections will be made by visiting during visits 2 and 3.
The study was conducted cross-over with two visits EEG recording, the order will be randomized injections:
* Sequence A during visit 2 followed by sequence B during visit 3
* or sequence B during visit 2
Saline
After randomization healthy volunteers or patients with idiopathic generalized epilepsy receive:
sequence B: 2 injections of saline
Apomorphine (Experimental product)
Dosage Form: Injection Dosage: 1 or 5 mg / kg
Route of administration: Subcutaneous
Duration of treatment: two injections of apomorphine followed by two injections of a placebo one week after or vice versa.
Two injections will be made by visiting during visits 2 and 3.
The study was conducted cross-over with two visits EEG recording, the order will be randomized injections:
* Sequence A during visit 2 followed by sequence B during visit 3
* or sequence B during visit 2
Interventions
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Apomorphine (Experimental product)
Dosage Form: Injection Dosage: 1 or 5 mg / kg
Route of administration: Subcutaneous
Duration of treatment: two injections of apomorphine followed by two injections of a placebo one week after or vice versa.
Two injections will be made by visiting during visits 2 and 3.
The study was conducted cross-over with two visits EEG recording, the order will be randomized injections:
* Sequence A during visit 2 followed by sequence B during visit 3
* or sequence B during visit 2
Eligibility Criteria
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Inclusion Criteria
* Men and women aged between 18 and 40
* Person affiliated to social security or beneficiary of such a regime
* idiopathic generalized epilepsy treated with lamotrigine, an association of lamotrigine, topiramate, levetiracetam, lamotrigine or levetiracetam alone (group patients) for at least 14 days without changing doses The idiopathic generalized epilepsy is defined by generalized seizures: generalized tonic-clonic seizures, absences or myoclonic seizures, excluding any other type of seizure, and electroencephalographic appearance following: presence of interictal EEG discharge generalized to type of spikes, spike-wave or wave polyspikes generalized, sporadic or rhythmic\> or = 3 Hz background activity is normal.
For healthy volunteers:
* Men and women aged between 18 and 40
* Person affiliated to social security or beneficiary of such a regime
Exclusion Criteria
* Deflecting protocol that can skew the primary endpoint
* Primary endpoint missing
* If the investigator considers the health of the subject is incompatible with the continuation of the study.
Criteria for non-inclusion
* For patients:
* The presence of interictal focal discharges on EEG previous
* The emergence of partial seizures
* Restless Leg Syndrome
* All non-antiepileptic treatment may affect levels of dopamine
* Current use of illicit drugs.
* A person deprived of liberty by judicial or administrative person being a measure of legal protection.
* Pregnant, parturient, lactating mother.
* For women, lack of effective contraception
* For healthy volunteers:
* Any medical treatment associated
* Current use of illicit drugs
* Pregnant, parturient, lactating mother
* For women, lack of effective contraception
* A person deprived of liberty by judicial or administrative person being a measure of legal protection.
18 Years
40 Years
ALL
Yes
Sponsors
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Institut National de la Santé Et de la Recherche Médicale, France
OTHER_GOV
Responsible Party
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Principal Investigators
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Laurent VERCUEIL, Doctor
Role: PRINCIPAL_INVESTIGATOR
Institut National de la Santé Et de la Recherche Médicale, France
Locations
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CIC Department - University Hospital of Grenoble
La Tronche, Isere, France
Countries
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References
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Ahmad S, Fowler LJ, Whitton PS. Effect of acute and chronic lamotrigine on basal and stimulated extracellular 5-hydroxytryptamine and dopamine in the hippocampus of the freely moving rat. Br J Pharmacol. 2004 May;142(1):136-42. doi: 10.1038/sj.bjp.0705737. Epub 2004 Mar 22.
Ahmad S, Fowler LJ, Whitton PS. Lamotrigine, carbamazepine and phenytoin differentially alter extracellular levels of 5-hydroxytryptamine, dopamine and amino acids. Epilepsy Res. 2005 Feb;63(2-3):141-9. doi: 10.1016/j.eplepsyres.2005.02.002.
Aymard G, Berlin I, de Brettes B, Diquet B. Pharmacokinetic-pharmacodynamic study of apomorphine's effect on growth hormone secretion in healthy subjects. Fundam Clin Pharmacol. 2003 Aug;17(4):473-81. doi: 10.1046/j.1472-8206.2003.00152.x.
Biraben A, Semah F, Ribeiro MJ, Douaud G, Remy P, Depaulis A. PET evidence for a role of the basal ganglia in patients with ring chromosome 20 epilepsy. Neurology. 2004 Jul 13;63(1):73-7. doi: 10.1212/01.wnl.0000132840.40838.13.
Blin O, Masson G, Azulay JP, Fondarai J, Serratrice G. Apomorphine-induced blinking and yawning in healthy volunteers. Br J Clin Pharmacol. 1990 Nov;30(5):769-73. doi: 10.1111/j.1365-2125.1990.tb03848.x.
Other Identifiers
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C10-27
Identifier Type: -
Identifier Source: org_study_id