Clinical Neuroscience

[Antinociceptive effect of vinpocetine - a comprehensive survey]


MAY 30, 2010

Clinical Neuroscience - 2010;63(05-06)

[Blockade of retrograde transport of nerve growth factor (NGF) in a peripheral sensory nerve is known to induce transganglionic degenerative atrophy (TDA) of central sensory terminals in the upper dorsal horn of the related, ipsilateral segments(s) of the spinal cord. The ensuing temporary blockade of transmission of nociceptive impulses has been utilized in the therapy of intractable pain, using transcutaneous iontophoresis of the microtubule inhibitors vincristin and vinblastin, drugs which inhibit retrograde transport of NGF. Since microtubule inhibition might inhibit (at least theoretically) mitotic processes in general, we sought to find a drug which inhibits retrograde transport of NGF without microtubule inhibition. Vinpocetine, a derivate of vincamine, which does not interfere with microtubular function, was found to inhibit retrograde axoplasmic transport of NGF in peripheral sensory nerves, similarly to vincristin and vinblastin. Blockade of NGF transport is followed by transganglionic degenerative atrophy in the segmentally related, ipsilateral superficial spinal dorsal horn, characterized by depletion of the marker enzymes of nociception, fluoride resistant acid phosphatase (FRAP) and thiamine monophosphatase (TMP) from the Rolando substance and by decrease of the pain-related neuropeptides substance P (SP) and calcitonin gene-related peptide (CGRP) from lamina I-II-III. Based upon these findings, it has been suggested that vinpocetine may result in a locally restricted decrease of nociception. Herewith, the structural and behavioral effects of perineurally administered vinpocetine are discussed. Nociception, induced by intraplantar injection of formalin, was mitigated by perineural application of vinpocetine; also formalin-induced expression of c-fos in the ipsilateral, segmentally related superficial dorsal horn, was prevented by this treatment. Since vinpocetine is not a microtubule inhibitor, its mode of action is enigmatic. It is assumed that the effect of vinpocetine might be related to interaction with membrane-trafficking proteins, such as signalling endosomes and the endocytosis-mediating „pincher” protein, involved in retrograde axoplasmic transport of NGF, or to interaction with glial elements, recently reported to be involved in the modulation of pain in the spinal cord. Based on animal experiments it is assumed that the temporary, locally restricted decrease of nociception, induced by vinpocetine applied via transcutaneous iontophoresis, might open up new avenues in the clinical treatment of intractable pain.]



Further articles in this publication

Clinical Neuroscience

[Neurology! Adieau? (Part 1)]


[The neurological practice suffered considerable changes during the last twenty years. The recent therapeutic methods and the acceptance of the ideology of evidence based medicine, which is based on confidence in statistics, changed the reasoning of the neurologists. Therapy protocols intrude into the field of individual medicine, and doctors accept treatment schemes to alleviate responsibility of their decisions. In contrast with this, recent achievements in pharmacogenetics emphasize the importance of individual drug therapies. The protocol of intravenous cerebral thrombolysis does not require defining the origin of cerebral ischaemia in the acute stage, therefore, this procedure can be regarded as human experiment. According to the strict protocol thrombolysis might be indicated only in 1-8% of patients with cerebral ischaemia. According to the Cohrane database more trials are needed to clarify which patients are most likely to benefit from treatment. Because of the change in therapeutic principles transient ischaemic attack has been newly defined as “acute neurovascular syndrome”. Multiplication of neurological subspecialties has been facilitated by the development of diagnostic tools and the discovery of effective new drugs. The specialization led to narrowing of interest and competency of clinicians. Several new neurological scientific societies were founded for the representation of specific disorders. In Hungary, between 1993 and 2000 nine scientific societies were grounded within the field of clinical neurology. These societies should be thankful to the pharmaceutical industries for their existence. In some European countries in 2007 only three neurological subspecialties were accepted, which are neurophysiology, neuro-rehabilitation and childneurology. Neuro-radiology is in the hands of general radiologists, the specialization is not granted for neurologists. Because of the subspecialization the general professionalism of neurologists has diminished. Among young neurologists the propedeutic skills suffered most seriously. Subspecialisation of teachers also interferes with the practice oriented teaching of medical students and residents.]

Clinical Neuroscience

[Neurology! Adieau? (Part 2)]


[Teaching of neurologists is indisposed worldwide. University tutors are engaged in teaching, research and patient-care. This triple challenge is very demanding, and results in permanent insecurity of University employees. To compensate for the insufficient clinical training, some institutes in the USA employ academic staff members exclusively for teaching. The formation of new subspecialties hinders the education and training of general neurologists. At the present four generations of medical doctors are working together in the hospitals. The two older generations educate the younger neurologists who have been brought up in the world of limitless network of sterile information. Therefore their manual skills at the bedside and knowledge regarding emergency treatment are deficient. Demographics of medical doctors changed drastically. Twice as many women are working in neurology and psychiatry than men. Integrity of neurology is threatened by: 1. Separation of the cerebrovascular diseases from general neurology. Development of "stroke units" was facilitated by the better reimbursement for treatment and the interest of the pharmaceutical companies. The healthcare politics assisted to split the neurology into two parts. The independent status of “stroke departments” will reduce the rest of clinical neurology to outpatient service. 2. The main argumentation to segregate the rare neurological diseases was that their research will provide benefit for the diseases with high prevalence. This argumentation can rather be considered territorial imperative. The separation of rare diseases interferes with the teaching of differential diagnostics during neurological training. The traditional pragmatic neurology can not be retrieved. The faculty of neurology could retain its integrity because of the improvement of diagnostic methods and the more and more effective drugs. Nevertheless, even the progression of neurological sciences induces dissociation of clinical neurology. Neurology shall suffer fragmentation if the professional authorities fail to control the separation of subspecialties, if teaching of future neurologists, including practical knowledge and skills of diagnostic decision making, is not supported.]

Clinical Neuroscience

[Image fusion guided brachytherapy of brain tumors]


[The paper is the summary of mostly published works of the clinical results of intracavitary Yttrium-90 colloid irradiation of recurrent cystic craniopharyngiomas, and Iodine-125 interstitial irradiation of gliomas, pinealomas, brainstem tumors, recurrent meningeomas, solid craniopharyngiomas and metastases. It concisely demonstrates the usefulness of image fusion in the verification of isotope seeds and catheters, the comparison of 125 Iodine stereotactic brachytherapy and LINAC radiosurgery modalities on physical dose distribution and radiobiological efficacy, and the analysis of volumetric changes after interstitial irradiation of gliomas. Results of the immunohistochemical study deal with the role of microglia/macrophage system in the tissue response to I- 125 interstitial brachytherapy of cerebral gliomas. Due to financial reasons, gamma knife and Linac are not available to many countries and neurosurgical institutes. In the absence of the above mentioned radiosurgical methods, we have shown brachytherapy as an alternative solution in the treatment of different types of inoperable or recurrent brain tumors. The observed results may be noticable at LINAC and gamma knife irradiation too.]

Clinical Neuroscience

[Clinical studies on pramipexol retard]


[Pramipexol retard is the newest drug for the treatment of Parkinson’s disease. The prolonged release of the agent in this preparation allows a more continuous dopaminergic stimulation than previous preparations, without reducing the agent’s already known and proven clinical efficiency. In addition, it has a more favourable adverse effect profile than previous preparations, and patient compliance can also be better as it needs to be taken only once daily. These benefits have been proven in recent clinical studies, of which the most important ones are reviewed here.]

Clinical Neuroscience

[Epidemiology of dementia in Hungary]

ÉRSEK Katalin, KÁRPÁTI Krisztián, KOVÁCS Tibor, CSILLIK Gabriella, GULÁCSI L. Ádám, GULÁCSI László

[Objective - To estimate the epidemiology and the distribution of disease severity of dementia in Hungary, using published data. To estimate the demented population of 2008 and to make a projection for 2050. Methodology - With an outlook for the international professional literature and the available Hungarian information we examine the epidemiology of dementia in Hungary by age-groups and disease severity (according to MMSE categories), then make our estimation for the entire population. Results - Based on the estimation of the number of demented people in Hungary there is a noticeable difference between the domestic and the internationally published data. According to previous Hungarian studies, the number of the demented subjects vary between 530 and 917 thousand patients. Multiplying the elderly age-group’s populations by the global prevalence data it results in 101 thousand of demented patients. Estimation by the domestic published data we remarkably overestimate the presumed value, whereas by using the global prevalence figures we underestimate. Conclusions - There is a strong need for a representative study to obtain exact figures on the prevalence of dementia in Hungary. Getting exact figures of the Hungarian prevalence of dementia it is a strong need an overall representative study. With the lack of it the health and social care systems are not able to prepare for providing the increasing number of patients.]

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