Antiparkinsonian activity of Tabebuia impetiginosa bark and biochemical analysis of dopamine in rat brain homogenates.

OBJECTIVES: Improving economy and well-being in developing nations like India has expanded life expectancy and changed the attention from transmittable to non transmittable diseases such as Parkinson's disease. Tabebuia impetiginosa has been utilized by cultivators as a general tonic, immunostimulant, adaptogen and also in motor disorders. The present investigation was to explore the antiparkinsonian activity of Tabebuia impetiginosa bark by experimental methods. MATERIALS AND METHODS: Control group-I was served with distilled water. Group-II was considered as pathological control [1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) 2mg/nostrils i.n, Reserpine 40mg/kg s.c, Haloperidol 0.5mg/kg, i.p]. Group-III served with standard drug (Apomorphine 40mg/kg, s.c). Group IV and V received aqueous extract of Tabebuia impetiginosa bark in doses of 300 and 500mg/kg/day respectively. Tremor, hypokinesia, muscular rigidity, catatonia, postural immobility, postural instability and catalepsy were assessed for antiparkinsonian activity. RESULTS: The bark extract served group exhibited the increased levels of dopamine (5700±1.84ng/g) when compared to control groups (4300±3.17ng/g). The extract at both the doses displayed a significant reduction in postural flexion, moderate decrease in tremor, muscular rigidity and postural immobility scores but do not exhibit significant lowering of hypokinesia score in reserpine induced Parkinsonian model. The reduction in catatonia and catalepsy scores is more remarkable in case of high dose of extract (500mg/kg) compared to standard drug in Neuroleptic induced Parkinsonism. CONCLUSION: The findings demonstrate that Tabebuia impetiginosa bark extract has significant anti-cataleptic potentials and the antioxidant effect of the bark may also be a significant contributor to its antiparkinsonian activity.

Treatment of subcutaneous nodules after infusion of apomorphine; a biopsy-controlled study comparing 4 frequently used therapies.

This study aimed to provide clinical evidence for existing treatments of subcutaneous nodules after subcutaneous infusion of apomorphine, using a biopsy-controlled prospective crossover design of four treatments. We demonstrated that dilution of apomorphine significantly improved patient satisfaction, while subcutaneous hydrocortisone reduced nodule size, however with no differences in the histopathology.

Effects of oral 3% hydrogen peroxide used as an emetic on the gastroduodenal mucosa of healthy dogs.

OBJECTIVE: To characterize the extent of mucosal injury on the upper gastrointestinal tract following oral administration of 3% hydrogen peroxide (H2 O2 ) to induce emesis in normal dogs. DESIGN: Prospective clinical study. SETTING: Specialty referral hospital. ANIMALS: Seven staff-owned, healthy, adult dogs. INTERVENTIONS: Six dogs were assigned to the H2 O2 group and 1 dog was assigned as the apomorphine control. Dogs were anesthetized for gastroduodenoscopy with gross inspection and gastroduodenal biopsies at time 0 and 4 hours, 24 hours, 1 week, and 2 weeks following administration of oral 3% H2 O2 or subconjunctival apomorphine. Gross esophageal, gastric, and duodenal mucosal lesion scoring was performed by 2 blinded, experienced scorers. Biopsy samples were evaluated histologically by a veterinary pathologist. MEASUREMENTS AND MAIN RESULTS: Grade I esophagitis was noted in 2 dogs at 4 hours and in 1 dog at 2 weeks, while grade III esophagitis was observed in 1 dog 1 week following H2 O2 administration. At 4 hours, gastric mucosal lesions were visualized in all dogs, and lesions worsened by 24 hours. Mild to moderate duodenal mucosal lesions were visualized up to 24 hours after administration. Histopathology identified the most severe gastric lesions at 4 hours as hemorrhage; at 24 hours as degeneration, necrosis, and mucosal edema; and at 1 week as inflammation. By 2 weeks, most visual and histopathologic lesions were resolved. No histopathologic lesions were identified at any time point in the dog administered apomorphine. CONCLUSIONS: Significant visual and histopathologic gastric lesions occurred following administration of 3% H2 O2 in all dogs. Less severe visual duodenal lesions were identified. As compared to H2 O2 dogs, minimal gross gastroduodenal lesions and normal histopathology were identified in the apomorphine control.

Continuous perioperative apomorphine in deep brain stimulation surgery for Parkinson's disease.

BACKGROUND: Patients with Parkinson's disease (PD) deprived of dopaminergic medication to facilitate awake testing during the deep brain stimulation (DBS) procedure are at increased risk of neurologic deterioration.. The aim of this survey was to demonstrate the safety of subcutaneous apomorphine treatment for reducing surgery-related neurologic deterioration in patients undergoing DBS surgery for PD. METHODS: Ninety-two patients who underwent DBS surgery for PD between 11/2007 and 10/2011 in our department were retrospectively analyzed for this survey. Demographic data, apomorphine dosage, side-effects and need of ICU/IMC stay were collected and analyzed. RESULTS: Seventy-two out of 92 patients (78.3%) received apomorphine treatment; main reason for omission of treatment was intolerable nausea (16/92, 17.3%). Apomorphine treatment was well tolerated and the most common side effect was nodular panniculitis. No severe complications were observed. No patient required ICU/IMC stay related to dopaminergic deprivation. CONCLUSIONS: Perioperative withdrawal of dopaminergic medication in PD patients leads to an increased risk of neurologic and respiratory deterioration during DBS procedures. These complications can likely be tempered using perioperative subcutaneous apomorphine as a substitute. Our 5-year experience indicates a reduction in postoperative neurologic deterioration and ICU/IMC stay need. We consider perioperative apomorphine safe during DBS surgery for PD.

Transplantation of melanocytes obtained from the skin ameliorates apomorphine-induced abnormal behavior in rodent hemi-parkinsonian models.

Tyrosinase, which catalyzes both the hydroxylation of tyrosine and consequent oxidation of L-DOPA to form melanin in melanocytes, is also expressed in the brain, and oxidizes L-DOPA and dopamine. Replacement of dopamine synthesis by tyrosinase was reported in tyrosine hydroxylase null mice. To examine the potential benefits of autograft cell transplantation for patients with Parkinson's disease, tyrosinase-producing cells including melanocytes, were transplanted into the striatum of hemi-parkinsonian model rats or mice lesioned with 6-hydroxydopamine. Marked improvement in apomorphine-induced rotation was noted at day 40 after intrastriatal melanoma cell transplantation. Transplantation of tyrosinase cDNA-transfected hepatoma cells, which constitutively produce L-DOPA, resulted in marked amelioration of the asymmetric apomorphine-induced rotation in hemi-parkinsonian mice and the effect was present up to 2 months. Moreover, parkinsonian mice transplanted with melanocytes from the back skin of black newborn mice, but not from albino mice, showed marked improvement in the apomorphine-induced rotation behavior up to 3 months after the transplantation. Dopamine-positive signals were seen around the surviving transplants in these experiments. Taken together with previous studies showing dopamine synthesis and metabolism by tyrosinase, these results highlight therapeutic potential of intrastriatal autograft cell transplantation of melanocytes in patients with Parkinson's disease.

The role of area postrema neurons expressing H-channels in the induction mechanism of nausea and vomiting.

The area postrema is one of the circumventricular organs, lacks a blood-brain barrier, and is well known as the chemoreceptor trigger zone for emesis. Area postrema neurons are sensitive to emetic chemical substances carried in the blood plasma. Our previous study demonstrated the presence of 3 types of neurons characterized by different ion channels expressed in each cell type, but the type or types of area postrema neurons involved in the induction of nausea and/or emesis have remained unclear. To clarify the role of the most populous cells, which express the hyperpolarization-activated cation channel (H-channel), in induction of nausea and/or emesis, we investigated the effects of ZD7288 (an H-channel inhibitor) on apomorphine-induced conditioned taste aversion (CTA) to saccharin and c-Fos expression in the area postrema. We found that ZD7288 inhibited the acquisition of CTA and reduced apomorphine-induced c-Fos expression in the area postrema, indicating the involvement of the cells expressing H-channels in the induction of nausea and/or emesis. Finally, we discuss the role of cells expressing H-channels in the mechanism of nausea and/or vomiting.

The role of endogenous neurotensin in psychostimulant-induced disruption of prepulse inhibition and locomotion.

The neuropeptide neurotensin (NT) is closely associated with dopaminergic and glutamatergic systems in the rat brain. Central injection of NT into the nucleus accumbens (NAcc) or peripheral administration of NT receptor agonists, reduces many of the behavioral effects of psychostimulants. However, the role of endogenous NT in the behavioral effects of psychostimulants (e.g. DA agonists and NMDA receptor antagonists) remains unclear. Using a NTR antagonist, SR142948A, the current studies were designed to examine the role of endogenous NT in DA receptor agonist- and NMDA receptor antagonist-induced disruption of prepulse inhibition of the acoustic startle response (PPI), locomotor hyperactivity and brain-region specific c-fos mRNA expression. Adult male rats received a single i.p. injection of SR142948A or vehicle followed by D-amphetamine, apomorphine or dizocilpine challenge. SR142948A had no effect on baseline PPI, but dose-dependently attenuated d-amphetamine- and dizocilpine-induced PPI disruption and enhanced apomorphine-induced PPI disruption. SR142948A did not significantly affect either baseline locomotor activity or stimulant-induced hyperlocomotion. Systemic SR142948A administration prevented c-fos mRNA induction in mesolimbic terminal fields (prefrontal cortex, lateral septum, NAcc, ventral subiculum) induced by all three psychostimulants implicating the VTA as the site for NT modulation of stimulant-induced PPI disruption. Further characterization of the NT system may be valuable to find clinical useful compounds for schizophrenia and drug addiction.

[Cutaneous necrosis at apomorphine injection points]. / Nécroses cutanées localisées aux points d'injection d'apomorphine.

BACKGROUND: Apomorphine is a specific dopaminergic agonist used in the treatment of severe fluctuations of Parkinson's disease, particularly in patients on L-dopa. The drug is usually given subcutaneously, either as several daily injections or via a continuous subcutaneous delivery system. We describe two cases of localized cutaneous necrosis at the points of subcutaneous apomorphine injection. OBSERVATIONS: Two male patients presenting Parkinson's disease were treated by subcutaneous injection of apomorphine. One month later, asymptomatic necrotic lesions measuring from 2 to 5 mm appeared at the injection sites. Complete blood count, standard and advanced coagulation studies and screening tests were normal. One patient had taken acetylsalicylic acid. A skin biopsy showed normal epidermis, oedema of the papillary dermis with perivascular lymphocytic infiltrates, reticular dermal infiltrate with neutrophils, and necrosis of the reticular dermis and hypodermis in one patient, and in the other, necrosis in the epidermis, dermis, hypodermis and skin appendages, with dermal leucocytoclastic vasculitis and cytosteatonecrosis. Due to the severity of necrosis, apomorphine was stopped, resulting in improvement of skin lesions in one patient. In the second, due to the localized nature of the lesions and the improvement in the patient's quality of life since the introduction of apomorphine, the drug was continued, resulting in the appearance of new lesions, which continued to be limited to the injection sites. COMMENTS: To our knowledge, this is the first description of biopsy-proven apomorphine-induced localized skin necrosis. Reported cutaneous side effects of the drug include pruritic subcutaneous nodules corresponding to panniculitis with large numbers of eosinophils, allergic contact dermatitis, pigmented nodules resulting from oxidation of apomorphine, and nonspecific rashes. Cutaneous necrosis at injection sites could arise through various mechanisms: localized vasoconstriction ("dopamine necrosis"), direct toxicity of the injected drug, local manifestations of pre-existent coagulation disorders, immunological mechanisms or poor administration technique involving intravascular injection. The specific pharmacodynamic properties of apomorphine rule out vasomotor phenomena in the aetiology of such necrosis. Screening tests for thrombophilia were negative in the first patient. Although the underlying mechanism of this form of necrosis remains unknown, an immunological mechanism of the immune complex type could be considered aetiologically relevant on histological grounds due to the presence of vasculitis in one of the two patients.

The delayed phase of cisplatin-induced emesis is mediated by the area postrema and not the abdominal visceral innervation in the ferret.

The anti-cancer chemotherapeutic agent cisplatin induces an acute (approximately 24 h) and delayed (approximately 24-72 h+) emetic response in humans; whereas the mechanism mediating the acute phase has been characterised, the delayed phase is relatively poorly understood. We have used nerve lesions (abdominal vagus, VX; greater splanchnic nerve, GSNX) and area postrema ablation (APX) in the ferret model of cisplatin (5 mg/kg, i.p.) delayed emesis and demonstrated that VX and VX+GSNX did not significantly modify the delayed emetic response (24-72 h), which consisted of 276.0+/-62.8 retches+vomits (R+V) in sham-operated ferrets and 167.2+/-34.0R+V and 214.8+/-40.2R+V, in the VX and VX+GSNX groups, respectively. APX virtually abolished the delayed phase of emesis and sham-operated ferrets had 93.0+/-22.9R+V whilst only 6.0+/-3.6R+V (p=0.009) were observed in APX animals. These data suggest that, in contrast to the acute emetic response triggered by cisplatin, the delayed phase does not rely on abdominal visceral afferents but is mediated via the area postrema.

Chemotherapy-induced kaolin intake is increased by lesion of the lateral parabrachial nucleus of the rat.

Anticancer agents, such as cisplatin, stimulate nausea, vomiting, and behaviors indicative of malaise. Rats and mice do not possess a vomiting response, and, therefore, in these species, the ingestion of kaolin clay (a pica response) has been used as an index of malaise. In the rat, cisplatin-induced kaolin intake is inhibited by antiemetic treatments. In addition, cisplatin activates vagal afferent fibers in the gut, and kaolin intake induced by cisplatin is largely dependent on an intact vagus. Nevertheless, little is known about the brain pathways controlling pica. We investigated the role of the lateral parabrachial nucleus (lPBN), a major visceral afferent link between the hindbrain and forebrain, in cisplatin-induced c-Fos expression and pica. Injection of cisplatin (6 mg/kg ip) produced c-Fos expression in the ventrolateral (external) lPBN, a region receiving viscerosensory input. In rats with bilateral ibotenic acid lPBN lesions, cisplatin treatment substantially increased kaolin intake compared with controls ( approximately 30 g vs. approximately 5 g, respectively, over 24 h). Food intake was reduced by cisplatin treatment and by apomorphine, an emetic agent that acts centrally. Unlike cisplatin, however, apomorphine stimulated kaolin intake to a similar degree in both the lesioned and control rats, suggesting that lPBN damage neither produces nonspecific effects nor enhances malaise in general. These data suggest that lPBN-lesioned animals not only demonstrate pica after cisplatin treatment, but, in fact, show an exaggerated response that is greatly in excess of any treatment known to produce kaolin intake in rats.

A prospective evaluation of efficacy and compliance with a multistep treatment approach for erectile dysfunction in patients after non-nerve sparing radical prostatectomy.

OBJECTIVE: To assess the response rate to different erectile aids in a consecutive series of patients treated with non-nerve sparing radical prostatectomy (NNSRP). PATIENTS AND METHODS: Ninety-four potent men were counselled about the different treatment options to restore an assisted erection before they had NNSRP. They were invited to participate in a multiphase protocol involving the sequential use of different erectile aids which aimed at restoring erectile function after surgery. The first proposed treatment was oral apomorphine sublingual. Patients with a positive response to the 1-item overall efficacy question and a minimum score of 3 in both question 3 and 4 of the International Index of Erectile Function were considered responders to oral pharmacotherapy. Treatment with sildenafil was then suggested to those not responding. If patients did not respond to oral pharmacotherapy a trial with a vacuum erectile device was offered; those not responding to this were then offered intracavernosal injection therapy with prostaglandin-E alone as the first option, followed by a mixture of vasoactive agents if needed. In those in whom injections also failed, a penile implant was recommended. At the 1-year follow-up visit all patients were offered a second trial with oral therapy regardless of the treatment currently in use. RESULTS: Seventy-six patients entered the protocol; there was no response to apomorphine. Five of 59 (8%) patients responded to sildenafil when they first used it at a mean of 7 months after NNSRP, while there were three additional responders in 22 patients who tried it for a second time a year later. Of patients achieving at least a complete tumescence sufficient for vaginal penetration, 52% and 60% were considered responders to the vacuum device and intracavernosal injections, respectively. Overall, 44% of patients enrolled in the protocol chose to use an erectile aid for at-home use. At the 1-year follow-up, only 20% of patients were still using an erectile aid, including two who had had a penile implant. CONCLUSIONS: Up to 10% of patients may achieve a clinically significant erection with sildenafil after NNSRP, but 80% will not be using any erectile aid at 1 year after surgery. In the present study protocol the proposed erectile aids were largely inadequate for treating the permanent erectile dysfunction that follows NNSRP.

The CB1 cannabinoid receptor agonist, HU-210, reduces levodopa-induced rotations in 6-hydroxydopamine-lesioned rats.

Parkinson's disease is a chronic neurodegenerative disease of the extrapyramidal system associated with dopaminergic neuronal loss in the basal ganglia. However, several other neurotransmitters, such as serotonin, gamma-amino-butyric acid and glutamate, are also related to the symptoms of Parkinson's disease patients and their response to levodopa treatment. The co-expression of cannabinoid and dopamine receptors in the basal ganglia suggests a potential role for endocannabinoids in the control of voluntary movement in Parkinson's disease. In the present study we treated unilaterally 2,4,5-trihydroxyphenethylamine (6-hydroxydopamine)-lesioned rats with the enantiomers of the synthetic cannabinoid 7-hydroxy-delta6-tetrahydrocannabinol 1,1-dimethylheptyl. Treatment with its (-)- (3R, 4R) enantiomer (code-name HU-210), a potent cannabinoid receptor type 1 agonist, reduced the rotations induced by levodopa/carbidopa or apomorphine by 34% and 44%, respectively. In contrast, treatment with the (+)- (3S, 4S) enantiomer (code-name HU-211), an N-methyl-D-aspartate antagonist, as well as the psychotropically inactive cannabis constituent: cannabidiol and its primary metabolite, 7-hydroxy-cannabinol, did not show any reduction of rotational behavior. Our results indicate that activation of the CB1 stimulates the dopaminergic system ipsilaterally to the lesion, and may have implications in the treatment of Parkinson's disease.

Action of metyrapone and tetracosactrin to modify cisplatin-induced acute and delayed emesis in the ferret.

Cisplatin 5 mg/kg, i.p., induced an acute (day 1) and delayed (days 2 and 3) emetic response in the ferret that was used to investigate the potential anti-emetic activity of metyrapone and tetracosactrin and their potential interaction. The 11beta-hydroxylase enzymes inhibitor metyrapone 10-30 mg/kg, i.p., dose dependently potentiated the acute cisplatin-induce retching+vomiting response by up to 219% at the highest dose (P<0.001) but failed to affect significantly delayed emesis (P>0.05). The adrenocorticotropic hormone (ACTH) mimetic tetracosactrin 0.1 mg/kg, i.m., antagonised significantly the acute and delayed emetic response by 98% (P<0.01) and 75% (P<0.001), respectively. The anti-emetic action of tetracosactrin on acute but not delayed emesis was prevented by combination with metyrapone 10 mg/kg, i.p. Tetracosactrin 0.1 mg/kg, i.m., failed to modify apomorphine (0.25 mg/kg, s.c.)-induced emesis. The potential anti-emetic mechanism of action of metyrapone and tetracosactrin to modulate emesis is discussed.

[Comparative experimental study of antiemetic action of latranum in radiation-induced vomiting and vomiting caused by apomorphine]. / Sravnitel'noe éksperimental'noe izuchenie antiémeticheskogo deistviia latrana pri rvote radiatsionnogo i apomorfinovogo proiskhozhdeniia.

The experiments on dogs showed that Latranum, a selective blocker of serotonin 5-HT3-receptors, has a moderate capacity to modify emetic reaction caused by dophamin-stimulating action of Apomorphinum. These results, taking in account of our preliminary experimental data obtained by a model of early radiation-induced emetic reactions, show that the high antiemetic effect of Latranum may affect another mechanisms of the initiation of early radiation-inducing vomiting which do not connect immediately with the chemoreceptor trigger zone.

[Apomorphine hyperpigmentation]. / Apomorphin-Pigmentierung.

A 72 year old bedridden, disoriented man presented with a continuously increasing number of blue nodules on his abdomen and both thighs. In addition, he had a melanoma on his left forearm (SSM, Clark level III, Breslow 0.75 mm), which lead to the clinical diagnosis of melanoma metastases. Biopsy of one of the blue nodules showed CD68 positive histiocytic cells loaded with brownish pigment granules and a lymphocytic infiltrate within the deep dermis and upper subcutis. The pigment reacted histochemically similarly to melanin. Melanocytes were absent at these sites. Because of the unexplained clinical and histopathological picture, the patient's history was reassessed and it was learned that the patient had received subcutaneous infusions of apomorphine for the past 10 years for the treatment of Parkinson's disease. By oxidation, apomorphine may be converted into tetrahydroisoquinoline-melanin, which apparently is the cause for the accumulation of pigment within the deep dermis.

Clinical and electrophysiological effects of apomorphine in Parkinson's disease patients are not paralleled by amino acid release changes: a microdialysis study.

We performed a microdialysis investigation of extracellular amino acid (glutamate and GABA) concentrations during sterotaxic neurosurgery (the implantation of permanent electrodes in the internal globus pallidus (GPi) or subthalamic nucleus (STN) for deep brain stimulation in advanced Parkinson's disease (PD) patients, after prolonged therapy wash-out). Electrophysiological single unit recordings and perioperative clinical status assessments were also performed. Amino acid levels were measured in the GPi and GPe (external globus pallidus) of three PD patients and in the STN of another three PD patients. Stable basal release values of the examined amino acids were obtained within one hour. In clinical "off" state, the basal levels of GABA in the GPi were double those in the GPe in all the three patients. This finding could represent a biochemical marker for GPi target identification in PD surgery. Acute subcutaneous apomorphine administration induced electrophysiological changes and clinical amelioration but did not change amino acid concentrations. This result could be due to methodological limitations of the microdialysis technique. Alternatively, it could suggest that the clinical effects of acute apomorphine might also be mediated by direct activation of dopaminergic receptors located in the output nuclei.

Intravenous apomorphine therapy in Parkinson's disease: clinical and pharmacokinetic observations.

Six patients with Parkinson's disease and refractory motor fluctuations, with severe subcutaneous (s.c.) nodule formation as a result of long-term s.c. apomorphine infusions, were switched to intravenous (i.v.) therapy via a long-term in-dwelling venous catheter. Five patients were followed-up for a mean of 7 months (range 0.5-18 months). All patients had plasma apomorphine concentrations measured at baseline during s.c. infusions and three had follow-up measurements when stabilized on i.v. therapy, to test the hypothesis that motor fluctuations in these patients are largely due to impaired absorption of apomorphine. The mean i.v. rate of 9.0 mg/h (range 5-14 mg) and 24-h dose of 256.7 mg (range 90-456 mg) of apomorphine were not significantly reduced compared with the s.c. route (9.24 mg/h and 243.4 mg). However, additional oral anti-parkinsonian medication was reduced by a mean of 59%, and 'off' time was virtually eliminated (mean reduction from 5.4 to 0.5 h per day, P< 0.05). There was also a significant reduction in dyskinesias and markedly improved quality of life. Pharmacokinetic analysis demonstrated more reliable and smoother delivery of apomorphine via the i.v. route, although 'off' periods were not always explained by low plasma apomorphine concentrations. Complication rates were high and included three unforeseen hazardous intravascular thrombotic complications, secondary to apomorphine crystal accumulation, necessitating cardiothoracic surgery. We conclude that i.v. apomorphine therapy holds promise as a more effective way of controlling motor fluctuations than the s.c. route. However, further preclinical research is required before i.v. Britaject apomorphine can be recommended for routine clinical practice. Even when stable plasma apomorphine concentrations were achieved, motor fluctuations could not be totally eradicated, suggesting that postsynaptic receptor changes may also play a role in the refractory 'off' periods in these patients.

Neuronal recordings in Parkinson's disease patients with dyskinesias induced by apomorphine.

Dopaminergic agents reverse parkinsonism but commonly induce dyskinesia in patients with Parkinson's disease (PD) on long-term levodopa therapy. The aim of this study was to determine the neurophysiologic correlates of the amelioration of parkinsonism and the involuntary movements produced by the dopamine agonist apomorphine. Seventeen PD patients were given apomorphine (2-6 mg) before surgery. Neural activity was recorded for individual neurons and for populations of neurons before and after apomorphine. Both internal (GPi) and external (GPe) segments of the globus pallidus were sampled in patients undergoing pallidal surgery. The subthalamic nucleus (STN) was sampled in STN surgery patients. Results suggest that dopaminergic agents act by decreasing GPi and STN activity, and increasing GPe activity, and that drug-induced dyskinesias results from a large reduction in GPi firing.

Apomorphine test: a predictor for motor responsiveness to deep brain stimulation of the subthalamic nucleus.

The value of the apomorphine test as a predictor of the clinical outcome of deep brain stimulation of the subthalamic nucleus (STN) was evaluated in patients with advanced idiopathic Parkinson's disease (IPD) or multiple system atrophy (MSA). Thirteen IPD patients with severe diurnal fluctuations and one MSA patient not responding to dopaminergic drugs were assessed with the Unified Parkinson's Disease Rating Scale (UPDRS) and the timed finger tapping test (FTT), measured preoperatively on and off apomorphine and postoperatively on and off STN stimulation. UPDRS motor items 20-25 were assessed intraoperatively on and off STN stimulation when the clinically effective target was approached. The motor response to immediate intraoperative and long-term STN stimulation was correlated with results of the apomorphine test. The response to immediate intraoperative STN stimulation was accurately predicted by apomorphine challenge in all 13 IPD patients. Clinical outcome following long-term STN stimulation was correlated significantly with preoperative changes due to apomorphine measured with the UPDRS motor scores (r = 0.7125, P < 0.01) and FTT (r = 0.9276, P < 0.001). Moreover, comparison of long-term STN stimulation to preoperative drug treatment displayed a significant reduction in the duration of off-phases and a significant increase in the duration of on-phases. However, in the single patient with MSA no beneficial response was obtained either to apomorphine or to STN stimulation intraoperatively and during the postoperative externalized test period. Our results indicate that the apomorphine test can predict the outcome of immediate and long-term STN stimulation and may help in the selection of candidates for surgery.