Browsing by discipline "Farmakologi"

Parkinson's disease is a chronic progressive neurodegenerative disorder, characterized by muscle rigidity, hypokinesia, tremors and bradykinesia. The cause of symptoms in Parkinson's disease is loss of dopaminergic nerve cells in the substantia nigra, which attenuates the nigrostriatal dopaminergic signaltransmission. Oxidative stress, mitochondrial dysfunction, protein misfolding and aggregation, inflammation, excitotoxicity, apoptosis and other routes for cell death, and loss of neurotrophic factors have shown to be mechanisms in the pathogenesis of Parkinson's disease. Microglia might have a double role in the pathogenesis of Parkinson's disease. Microglia stimulated by Į- synuclein does not only produce toxic factors such as certain cytokines and reactive oxygen and nitrogen species, which contribute to the neuronal cell death but also produce anti-inflammatory cytokines and neurotrophic factors, which can be neuroprotective. Deeper knowledge of the mechanisms underlying Parkinson's disease is needed for developing restorative medicines. Three different neurotrophic factor families are known to be important in the research of Parkinson's disease. The GDNF-family consists of glial cell line-derived neurotrophic factor (GDNF), neurturin (NRTN), artemin (ARTN) and persephin (PSPN). The neurotrophin-family consists of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and neurotrophins NT3 and NT4/5. The most recently discovered family is the MANF-family, which consists of mesencephalic astrocyte-derived neurotrophic factor (MANF) and conserved dopamine neurotrophic factor (CDNF). In Parkinson's disease the neurotrophic factors could stop, slow or ideally even reverse the neurodegeneration in the dopaminergic system and decrease the functional decline of the neurons. Research has already shown that GDNF has both a neurorestorative and neuroprotective effect in animal models of Parkinson's disease. Clinical trials have however shown controversial results. The challenge with neurotrophic factors can be the administration to the brain through the blood-brain-barrier, sideeffects because of receptor binding in other organs or sites of the body and low diffusionrate. Research of both MANF and CDNF has shown promising neurorestorative and -protective results in vivo. Local diffusion of MANF has been shown to be better than of GDNF. In this Master's thesis research was done on whether MANF and CDNF have a neurorestorative effect on the dopaminergic nerve cells in mixed primary culture in vitro after 6-OHDA exposure. The aim of the study was to receive information about whether MANF and CDNF are as effective as GDNF at repairing celldamages caused by 6-OHDA in vitro in this experimental model. GDNF was used as a posivite control in this study. The results from this study suggest that MANF might have a neurorestorative effect, but this effect is much smaller than with the neurotrophic factor GDNF. The results show no neurorestorative effect with CDNF. Neither the dopamine uptake nor the tyrosine hydroxylase staining showed statistical significance.

Histamine acts as a neurotransmitter in the central and peripheral nervous system and it has a role in various body functions. Histamine neurons spread widely to most of the central nervous system where histamine has an important role in sleep-wake cycles, regulation of appetite, and motor functions. The effects of histamine are mediated mostly by H1-, H2- and H3-receptors in the central nervous system. The synthesis of histamine and the release of histamine from the presynaptic nerve endings are regulated by H3-receptor via negative feedback. H3-receptors are located also on the presynaptic cell membranes of other neurons where they regulate the release of other neurotransmitters. Several animal experiments have shown that H3-receptor-mediated mechanisms have been observed to have an important role in the regulation of the motor functions together with other neurotransmitter systems especially in the basal ganglia area. The histaminergic system is involved in the patophysiology of diseases such as Parkinson’s disease, Tourette’s syndrome and Huntington’s disease where motor performance is impaired. Functional, physiological and genetical changes in the histaminergic system have been observed in patients with these diseases. There are no clinically used histaminergic compounds for the treatment of these diseases, though recently in animal experiments the histaminergic compounds have proved to be promising. The aim of this Master’s thesis study was to examine the effects of histamine deficiency in the brain on the levodopainduced dyskinesias in histidine decarboxylase knock-out mice (HDC KO) (n=9) and wild-type mice (n=12) in a 6-OHDA mouse model of Parkinson’s disease. The mice were injected with a neurotoxic 6-OHDA solution (3 μg) into the right medial forebrain bundle to cause a unilateral dopaminergic lesion. The success of degeneration of dopaminergic neurons were measured by a rotating rod test and amphetamine-induced (2.5 mg/kg) and apomorphineinduced (0.5 mg/kg) rotameter tests. A daily treatment of levodopa and benserazide (4.5 mg/kg, 1.125 mg/kg) was initiated after the behavioural studies for 10 days. On the last day of the treatment the dyskinesias of the mice were filmed for one minute after 20, 40, 60, 80, 100 and 120 minutes after levodopa dose. After the filming, the mice were killed by decapitation and their middle brains were collected for immunohistochemical studies to measure the extent of the dopaminergic lesion. No statistically significant difference was observed between genotypes in levodopa-induced dyskinesias. In previous studies of our study group more severe levodopa-induced dyskinesias were observed in HDC KO mice when the dopaminergic lesion was caused in the striatum in the 6-OHDA mouse model. The degenerated brain area and thereby the extent of the lesion may have importance in observing the difference between levodopa-induced dyskinesias. In this Master’s thesis study the dopaminergic lesions were equally successful with both genotypes. Therefore differently successful lesions between the genotypes can not be the reason why the difference in genotypes in levodopa-induced dyskinesias was not observed. HDC KO mice were observed to have significantly increased ipsilateral rotational behaviour induced by amphetamine in amphetamine-induced rotametry. Previous studies have shown that HDC KO mice have increased dopamine release and high dopamine metabolite levels which might explain the increased rotational behaviour induced by amphetamine in this study. The observations of earlier studies and this Master’s thesis study verify the relation between histaminergic and dopaminergic systems in motor functions.

Parkison's disease is a progressive neurodegenerative disorder that is characterized by degeneration of dopaminergic neurons in the nigrostriatal dopamine pathway. This is responsible for the major symptoms of Parkinson's disease. The current therapies only treat symptoms without being able to slow down, or reverse, the neurodegenerative process. Therefore current research is directed toward prevention of dopaminergic neuron degeneration. Prolyl oligopeptidase (POP) is a serine peptidase which cleaves small proline-containing peptides. A number of neuropeptides are affected in Parkinson's disease and POP contributes to the degradation of many of these neuropeptides. Reduction in POP activity has observed in Parkinson's disease. However, it is not known if changes in POP activity were a cause or a consequence of Parkinson's disease. POP inhibitors are substrate-like compounds. In our study we used KYP-2047, a novel brain-penetrating POP inhibitor. Administration of KYP-2047 has previously been shown to increase slightly neurotensin levels after a single dose. Neurotensin is an endogenous neuropeptide that has antidopaminergic actions in the brain. A number of neurotensin receptors has been observed to decrease in substantia nigra and striatum after degeneration of nigrostriatal pathway in laboratory animals or Parkinson patients. When given into the brain, neurotensin and neurotensin analogs have decreased rigidity and tremor caused by 6-hydroxydopamine (6-OHDA). The aim of this study was to determine the interactions between POP and neurotensin and their connections with dopamine deficit in a rat model of Parkinson's disease (the turning model of Ungerstedt). POP activity was also studied. In this study two different kinds of lesions were used. Intracerebral injections of 6-OHDA were given either into the MFB (medial forebrain bundle) or striatum. Rotational behaviour was measured five weeks post-lesion. The MFB lesion Wistar rats were given levodopa/carbidopa -suspension with KYP-2047 or entacapone or both of them. The striatum lesion rats were given amphetamine with KYP-2047. Studies were organized in a cross-over manner once a week. Rotational behaviour did not change when a POP inhibitor was given suggesting that neurotensin levels were apparently not much changed. Differences in POP activity assay were not noticed when compared to normal and lesioned cerebral hemisphere. This indicates that there is no POP in long dopaminergic neurons.

Neuronal nicotinic receptors are widely expressed throughout the brain and they facilitate fast synaptic neurotransmission. They are also involved in regulation of the release of other neurotransmitters like GABA, dopamine and glutamate. The most common subtypes are alfa4beta2 and alfa7 subunits containing receptors. Neuronal nicotinic receptors are involved in nicotine addiction but also in many neurological diseases like Alzheimer's disease, schizophrenia, depression and attention deficit/hyperactivity disorder. The cholinergic stimulation enhances cognition in vivo and in human. There is not many drugs on the market that act via nicotinic receptors but many drug companies have new nicotinic agonists and antagonist under clinical research. When using nicotinic receptor agonists the problem is desensitization, which occurs in alfa7 nicotinic receptor rapidly after agonist exposure. When desensitized the receptor no longer responds to agonist even if it is there available to bind to receptor. The desensitization may lead to tachyphylaxis and losing of the clinical effect. Conventional agonists, like acetylcholine, bind to the binding site located in the extracellular part on nicotinic receptor subunit. There is also some other binding sites, which are called allosteric binding sites. It has been found out, that allosterically binding ligands, for example PNU-120596, can cause potentiation of agonist induced responses and/or prevent desensitization of receptor. These kinds of agents are called positive allosteric modulators and they are considered to be a new therapeutic option for CNS diseases containing cholinergic deficits. The mechanism of action of positive allosteric modulators is so far unclear. The purpose of my study was to characterize positive allosteric modulators on alfa7 nicotinic receptor. It had been found out earlier in the Millar laboratory that mutation L247T in the transmembrane domain converts positive allosteric modulators to agonists. The aim was to use site-directed mutagenesis to generate mutation in the agonist-binding site of alfa7 and alfa7L247T receptors and see how it effects on the ability of PNU-120596 to act as an agonist on the receptor. Second aim was to generate a mutation in the transmembrane part of the receptor to an assumed binding site of allosteric potentiators' and test how it effects on allosteric potentiator's ability to act as an agonist on the alfa7L247T. Mutated receptors were expressed on oocytes by microinjeting the mRNA into oocyte. The function of receptors was studied with electrophysiology using two-electrode voltageclamp technique. All the mutations were successfully inserted in nicotinic receptor alfa7 and alfa7L247T. Mutation in orthosteric agonist binding site had a very profound effect on wild type alfa7 receptor; it had an effect on either acetylcholine binding or receptor gating. It was not possible to record any proper responses neither with acetylcholine nor with PNU-120596. In the double-mutated receptor alfa7W149M/L247T the W149M mutation had a much greater effect on dose-response curves than it had on PNU-120596 curves compared with alfa7L247T. The transmembrane domain mutation M253L did not have much effect on PNU-120596's ability to act as an agonist to alfa7L247T and either it did not effect on acetylcholine dose-response curves. The results from this study support the previous results that the binding site of positive allosteric modulators is located in the transmembrane domain of the alfa7 receptor. The results are little controversial with the M253L mutation but because the L247T mutation has so profound effect on the function on alfa7 receptor it might be that it masks the other mutation which is located quite close to it. On the other hand it might be so that the amino acid M253 has only effect on the receptor's ability to be potentiated not the allosteric binding.

Parkinson's disease is characterized primarily as a bradykinetic disorder with severe nigral cell loss. In addition to motor symptoms, up to 85 % of patients with Parkinson's disease experience pain and in about 60 % of cases pain is related to Parkinson's disease. Most of it is classified as musculoskeletal pain. Bradykinesia and muscle cramps lead to pain by causing malpositions of joints and trunk. Up to 40 % of parkinson patients experience pain caused by dystonia. Neuritic or radicular pain is also related to Parkinson's disease. Less than 10 % of patients have primary central pain. Pain threshold and nociceptive flexon reflex threshold are lower among patients with Parkinson's disease than in healthy subjects. Common comorbidities, namely restless legs syndrome and depression can also exacerbate pain. The pathology of pain in patients is not well understood. It is known that basal ganglia take part in pain perception and modulation. Lesions in basal ganglia can interfere pain perception and cause the exacerbation of pain. The modulation of pain in central nervous system is altered and descending inhibitory tracts are thought to work insufficiently. Levodopa alleviates the pain in about 60 % of patients with Parkinson's disease suffering from pain. Levodopa normalizes dopamine function at least partly in basal ganglia and that way alleviates the pain caused by dysfunction of dopamine tracts. Levodopa relieves motor symptoms and so alleviates the secondary pain caused by muscle cramps and stiffness. Levodopa raises the pain thresholds of patients to normal level. Levodopa may have also a direct analgesic effect via dopamine D2 receptor activation. The mutations of the gene that codes catechol-O-methyltransferase (COMT) change its activity and are related to pain perception. Low COMT activity is related to several functional differences including increased sensitivity to pain and increased response to opioids. Also COMT inhibitors sensitize mice and rats to pain. The mechanism underlying the sensitization is not well understood. We examined the effects of COMT gene disruption and COMT inhibition in acute pain models. In the first part of our study, we examined the effect of COMT inhibitor OR-486 in COMT deficient mice. We tried to clarify wether sensitization to pain is caused by COMT inhibition or some other mechanism. We also tested the effects of endogenous opioids (swim stress) and exogenous opioid (morphine) in COMT deficient mice. In the second part, we tested the effects of an atypical COMT inhibitor CGP 28014 in acute pain models. CGP 28014 does not inhibit COMT in vitro but it inhibits the Omethylation of catecholamines in vivo. The main finding of our study was the sensitization to pain caused by CGP 28014. The result gives support to hypothesis claiming that sensitization to pain is caused by O-methylation of catecholamines. The results of our study are also in line with the theory that low COMT activity is related to pain sensitization and increased response to opioids.

Obesity is considered one of the major public health challenges. One way to control obesity is to regulate appetite. Because brain is the primary regulative unit responsible for food intake, the research in this field has now been allocated especially to the central nervous system. The aim of this thesis was to clarify the role of cholinergic projections from pedunculopontine tegmentum (PPT) to lateral hypothalamus (LH) in food intake. In this study, DREADD-technology (designed receptors exclusively activated by designer drugs) based on chemogenetics was utilized with a gene manipulated mouse strain. For the experimental part of this work the mice were divided in three separate groups: one transducted with an activating DREADD-receptor (hM3Dq), one transducted with an inhibiting DREADD-receptor (hM4Di) and one transducted only with a fluorescent protein called m-Cherry. The last group was also defined as a control group of this study. In addition, the gene which coded m-Cherry fluorescent protein was transducted together with hM3Dq- and hM4Di-receptor genes for the first two groups to be able to examine the receptor expression later. At the baseline level, no differences were observed in food intake between the three study groups. The food intake did not differ between the groups while clozapine-N-oxide (CNO), a selective DREADD-receptor ligand, was administered straight into the LH area (0,03 µg/injection) with or without fasting of the animals. While administrating CNO to the mice intraperitoneally (1 mg/kg), the hM3Dq-group mice were observed to consume more food compared to the hM4Di-group or the control group. This difference was detected while food consumption was examined cumulatively during total four measuring hours. When the animals were fasted before the intraperitoneal administration test, however no differences were found between the study groups regarding food intake. As a conclusion of this study, cholinergic projections from pedunculopontine tegmentum (PPT) to lateral hypothalamus (LH) were not regulating food intake in mice. However, the cholinergic cells in PPT and some of their axons might be involved in the regulation of food intake while the food consumption is studied continuously and long-term. More studies are required to better define the role of the cholinergic projections from pedunculopontine tegmentum (PPT) to lateral hypothalamus (LH) in food intake.

Actinic keratoses are premalignant skin lesions caused by sun UV-radiation. A small portion of these lesions progress into invasive squamous cell carcinoma over the years. Actinic keratoses are a growing problem in the healthcare around the world. P53 mutations are found in actinic keratosis and adjacent areas. Treatment options include surgical removal, cryotherapy, local treatment creams such as immunomodulators, and photodynamic therapy (PDT). Aminolevulenic acid (ALA) is an endogenous light-sensitizer used in PDT and methylaminolevulinate (MAL) and hexylaminolevulinate (HAL) are its esters. Either artificial light or daylight can be used as a light source in PDT. In PDT light activates the photosensitizer, which initiates a photochemical reaction and target cell destruction. The most common side effects of PDT are erythema and pain during treatment. The benefits of PDT are good cosmetic outcome and the possibility to treat large areas. In the present study 3 light-sensitizers (BF-200 ALA, MAL, HAL 0,2 % and 2 %) were tested on healthy volunteers to compare the skin irritation, pain and fluorescence caused by the treatment. Fluorescence intensity reflects PpIX production capacity. The second part of the present study was a clinical study comparing BF-200 ALA and MAL in treatment of actinic keratoses with daylight-PDT. Each patient received both light-sensitizers on opposite sides of the head and the results were evaluated 3 months after treatment. On healthy skin BF-200 ALA, MAL and HAL 2 % caused more irritation compared to HAL 0,2 %. HAL 2 % didn't differ from ALA and MAL-groups in severity of reactions, erythema or fluorescence photobleaching. In HAL-treated areas pain was smaller than in ALA- and MAL-groups. However, in lesional skin there might be differences in absorption, distribution and PpIX formation. Both BF-200 ALA and MAL were effective in daylight-PDT and there were no significant differences between the groups in either efficacy or pain caused by the treatment. Long-term follow up is still required to confirm if the results sustain.

Prolyl oligopeptidase (PREP) is a serine protease which is extensively present in the mammalian system and especially abundant in the brain. Despite the long research history of PREP its physiological function has remained unclear. PREP has been suggested to regulate the functions of many bioactive peptides by hydrolysis and on the other hand to participate in several intracellular processes probably via direct protein-protein interactions. One of the functions suggested for PREP is the regulation of the brain neurotransmitter systems and based on, for instance, the location in the brain PREP has been connected to both excitatory and inhibitory neurotransmitter systems. The literature review of this thesis first describe the brain neurotransmitter systems associated to PREP in general with some examples of diseases related to their malfunctions. In addition the structure of PREP and its location in the brain, both subcellular and cellular levels, and in distinct neurotransmitter systems, are presented, after which the different proposed functions for PREP are reviewed. The aim of the experimental part of this thesis was to investigate the effects of PREP on the brain neurotransmitter concentrations in the mouse nigrostriatal pathway and also to mouse motor behavior. The main research methods were microdialysis, tissue assays and cylinder test. The study was composed of two sections with five week duration each. The first section was performed with wild-type mice expressing naturally PREP and the second section with PREP-knockout (ko) mice and their wild-type littermates. The mice were injected unilaterally above the substantia nigra with adeno associated (AAV1) hPREP viral vector or with AAV1-eGFP (green fluorescent protein) viral vector as a control treatment. The cylinder test was carried out before the injection, and two and four weeks afterwards. Microdialysis was used to study the actions of PREP on the extracellular concentrations of dopamine (DA) and its metabolites dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), gamma-aminobutyric acid (GABA) and 5-hydroxyindoleacetic acid (5-HIAA), the major metabolite of serotonin (5-HT). In addition to the baseline assay the concentrations were measured after two amphetamine treatments (10 and 30 µM) administered via the microdialysis probe. The probe guide cannulas were inserted to mice striatums 1-2 weeks before the microdialysis measurement. In the end of the experiment the tissue concentrations of DA, DOPAC, HVA, 5-HT and 5-HIAA were measured from striatum and substantia nigra. Both the microdialysis and tissue sample concentrations were quantified with high performance liquid chromatography. In the first study section the PREP enzyme activity was also determined from striatum. Neither the complete deprivation nor over-expression of PREP in the nigrostriatal pathway had clear or consistent effects on the levels of neurotransmitters studied when compared to naturally occurring PREP expression. When comparing the differences between control treated groups of PREP-ko and littermate mice, a greater amphetamine stimulated DA-levels was seen in the former group proposing negative regulatory influence of PREP. In both study sections the tissue assay results were difficult to interpret due to observed responses also with AAV1-eGFP control treatment in comparison with untreated side of the brain. This was seen as a lower DA- and DOPAC-levels in substantia nigra and thus the meaning of the changes caused by PREP treatment is hard to comprehend. The results of the cylinder test may implicate some protective effect of the PREP-ko-genotype against viral vector injections in general. Then again the existence of compensatory mechanisms is possible when using knockout animals and thus the genotype differences are hardly ever unequivocal. The results of this thesis do not suggest outright regulatory effects of PREP on the neurotransmitter functions in the mouse nigrostriatal pathway although the confirmation of this requires further studies, especially in regard to GABAergic and glutamatergic systems. Studies should include a scale of different behavioral tests of motor activity and repeated microdialysis experiment with some defining method changes. The possible function and mechanisms of PREP as a regulator of neurotransmitter intake or release is rationale to study at molecular level with applicable methods.

Adverse drug events (ADE) are a major problem which deteriorates the quality of drug therapy. They cause significant morbidity and mortality each year. ADEs are often caused by incompatible drug combinations, drug-drug interactions (DDIs). Interprosessional collaboration between health care professionals is important in improving medication safety and preventig drug interactions. The aim of this study was to investigate the most common clinically significant drug-drug interactions in outpatient care and the role of pharmacist in preventing them. The study material was an interaction data which was collected in Helsinki University Pharmacy during August 2015. DDIs and the action needed by presecribers or pharmacists to handle them were collected. Only clinically significant interactions of the SFINX interaction database i.e. D- and C-interactions were recorded. The most common D-interactions (interactions to be avoided) were fluoroquinolones or tetracyclines combined with metal ions (calcium, iron, magnesium, aluminium) (14.7 % of D-interactions) and codeine or tramadol combined with CYP2D6 enzyme inhibiting antidepressants (12.6 %). C-interactions concerned most commonly interactions between antihypertensive drugs and NSAIDs (26.2 % of C-interactions). 59.6 % of D-interactions were interactions that might result in adverse drug reactions and 40.4 % were interactions that might result in therapeutic failure. For C-interactions numbers were 49.4 % and 50.6 %, respectively. Only a few interactions (1.6 %) led to contact with the prescriber from the pharmacy, and more often (1.8 %) the pharmacist advised the patient to contact the prescriber. 32.6 % of the interactions led to pharmacist's advice. The most typical interactions which can be prevented by pharmacist's advice were chelation interactions which can be prevented by taking drugs many hours apart from each other. 59.7 % of the interactions produced no action in pharmacy. Those concerned situations where the prescriber had planned the treatment and weighed up the benefits and risks of the medication, or interactions where the drugs had been in contemporary use for a long time, and thus the pharmacist assumed that the prescriber had planned the treatment. Pharmacists should intervene in drug-drug interactions easier. To avoid unnecessary calls, communication between prescribers and community pharmacies should be developed. Pharmacists' role in preventing DDIs could be improved for example by education and by updating the operations models in collaboration with other health care. Safe and efficient drug treatment should be ensured with interprofessional collaboration, and the responsibility should not be shifted to the patient alone.

Parkinson's disease is a progressive neurodegenerative disease. The incidence of the disease is 1.5-2 per cent after age 60. Typical symptoms are tremor, rigidity and bradykinesia. At the late stage of the disease patients have psychic disorders, for example dementia, anxiety and depression. Motor impairment is caused by degenerative loss of dopamine cells in nigrostriatal tract. Current treatment of the disease relieves the symptoms but it cannot stop or slow the progress of the disease. Neurotrophic factors and gene therapy have been trialled to improve the treatment of Parkinson's disease and the results have been encouraging. Neurotrophic factors are proteins that regulate actions of neurons. It has been discovered that they are neuroprotective and neurorestorative. The results with glial cell line-derived neurotrophic factor (GDNF) have been encouraging in in vivo studies of Parkinson's disease. There has been variability in success of clinical trials though. GDNF degrades quickly in vivo but overexpression of GDNF in cells can be produced with viral vector adeno-associated virus. Two different forms of GDNF, pre-α-pro-GDNF (α-GDNF) and pre-β-pro-GDNF (β-GDNF), are produced as precursors and they are activated proteolytically. Based on in vitro studies, some differences in secretion of precursors have been discovered. α-GDNF is secreted constitutively and secretion of β-GDNF is dependent on physiological stimulation. Previous in vitro studies have focused on α-GDNF, but β-GDNF might be a better solution for treating Parkinson's disease based on physiological regulation system. Cerebral dopamine neurotrophic factor (CDNF) is recently discovered and less studied than GDNF. It has been discovered that CDNF also has neuroprotective and neurorestorative effects in animal models of Parkinson's disease. The aim of the first part of this study was to discover the neurorestorative effect of single injection of CDNF injected above substantia nigra for rats that received injection of 6-hydroxydopamine (6-OHDA) into medial forebrain bundle. One week later rats received PBS, GDNF or CDNF injection. The degree of the lesion was estimated with apomorphine (0.1 mg/kg s.c.) or d-amphetamine sulphate (2.5 mg/kg) induced rotation test. The rats were perfused nine weeks post-lesion and their brains were sliced. Tyrosine hydroxylase (TH) positive dopamine cells were stained by immunohistochemistry. The amount of TH positive cells in substantia nigra was counted and optical density of TH positive fibres in striatum was measured. The aim of the second part of the study was to research the neuroprotective effect of two different precursors of GDNF, dsAAV1-pre-α-pro-GDNF and dsAAV1-pre-β-pro-GDNF, given with viral vectors. The dopamine cells in nigrostriatal tract were destroyed with a 6-OHDA injection into striatum and viral vectors were injected two weeks later. Rats in control group received injection of dsAAV1-GFP. The degree of the lesion was evaluated with d-amphetamine sulphate (2.5 mg/kg) induced rotation tests and cylinder test. The rats were perfused eight weeks post-lesion and their brains were processed for immunohistochemistry. The results of the study were interesting and supporting previous studies. The success of the neurotrophic factor treatment is dependent on a successful injection of protein or viral vector, and the dose is dependent on the size of the lesion. Neurotrophic factors and gene therapy needs to be studied more before wide clinical usage.