Dopamine receptors in striatum are important for healthy brain functioning and are the target of levodopa-based therapy in Parkinson's disease. Lateralization of dopaminergic neurotransmission in striata from different hemispheres occurs in patients, but also in healthy individuals. Our data show that the affinity of dopamine binding to dopamine D1 receptors is significantly higher in left than in right striatum. Analysis of data from radioligand binding to striatal samples from naïve, 6-hydroxydopamine lesioned, levodopa-treated and levodopa-induced dyskinetic rats shows differential receptor structure and gives hints on the causes of right/left lateralization of dopamine binding to striatal D1 receptors. Moreover, binding data showed loss of lateralization in levodopa (L-DOPA)-induced dyskinetic rats.

• MeSH
• 2,3,4,5-tetrahydro-7,8-dihydroxy-1-fenyl-1H-3-benzazepin farmakologie   MeSH
• benzazepiny farmakologie   MeSH
• corpus striatum metabolismus   MeSH
• dopamin metabolismus   MeSH
• funkční lateralita * účinky léků   MeSH
• polékové dyskineze metabolismus   MeSH
• potkani Wistar MeSH
• receptory dopaminu D1 metabolismus   MeSH
• receptory dopaminu D3 agonisté   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• corpus callosum patofyziologie   patologie   účinky léků   MeSH
• degenerace nervu chemicky indukované   patologie   MeSH
• finanční podpora výzkumu jako téma MeSH
• funkční lateralita fyziologie   účinky léků   MeSH
• krysa rodu rattus MeSH
• mozková kůra fyziologie   patologie   účinky léků   MeSH
• status epilepticus chemicky indukované   patofyziologie   patologie   MeSH
• zvířata MeSH
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• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH

• MeSH
• biomedicínský výzkum MeSH
• funkční lateralita fyziologie   účinky léků   MeSH
• lidé MeSH
• poruchy spojené s užíváním opiátů diagnóza   psychologie   MeSH
• psychofyziologie metody   statistika a číselné údaje   MeSH
• závislost na heroinu diagnóza   psychologie   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH

The bioelectrical activity of the cochlea, without any ipsilateral acoustic stimulation, was recorded in awake guinea pigs (GPs) between electrodes chronically implanted at the round window (RW) and the skull. Measuring its power in the band centered around 1.0 kHz (0.5-2.5 kHz) provided an indirect measure of the ensemble background (EBA) activity of the eighth nerve. Contralateral white-noise (CLWN) stimulation reduced this EBA, presumably by activation of medial olivocochlear fibers. The aim of the investigation was to validate measurements of EBA and of its contralateral suppression in order to study the medial efferent function. The first goal was to find the best conditions for recording the EBA in the absence of ipsilateral stimulation and for studying its suppression by contralateral acoustic stimulation, which implies that no noise was generated by the experimental animal. Thus recordings were compared in normal, awake GPs and in GPs under sedation with xylazine, anesthetized with a combination of xylazine and ketamine, and with and without temperature regulation. In order to monitor the effects of sedation and anesthesia, the recordings were analyzed not only in the 0.5- to 2.5-kHz frequency band but also in the other frequency bands, 5-50 Hz, 50-150 Hz, and 150-500 Hz, which presumably include general central and neuromuscular contributions. The results show that sedation with xylazine accompanied by regulation of body temperature does not affect the EBA value nor its contralateral suppression. Nevertheless, anesthesia should be avoided, even with control of body temperature. The second goal of this study was to identify the specific cochlear contribution to the raw RW signal. Thus recordings were performed in normal and deafened animals and analyzed in the frequency band 0.5-2.5 kHz and also in the other frequency bands of 5-50 Hz, 50-150 Hz, and 150-500 Hz. The results indicate that most of the cochlear activity lies in the frequency band 0.5-2.5 kHz, with also some minor contribution coming from the 150- to 500-Hz band. Analysis and comparison of power values in the different conditions indicate that specific cochlear EBA power was about 60 microV2. From a commonly accepted mean background discharge rate of 50 spikes/s (sp/s), the EBA power without CLWN should have been around 4.4 microV2 if the fibers' activity was random. This difference suggests that there is probably some degree of synchrony between individual fibers. There was a reduction of approximately 45% during CLWN stimulation. This suppression might correspond to a reduction in both discharge rate and synchrony of the fibers.

• MeSH
• akustická stimulace MeSH
• aminoglykosidy MeSH
• anestezie MeSH
• antibakteriální látky farmakologie   MeSH
• diuretika farmakologie   MeSH
• funkční lateralita fyziologie   účinky léků   MeSH
• furosemid farmakologie   MeSH
• hluchota patofyziologie   MeSH
• hypnotika a sedativa * farmakologie   MeSH
• kochlea fyziologie   účinky léků   MeSH
• kyselina ethakrynová farmakologie   MeSH
• morčata MeSH
• nervus vestibulocochlearis fyziologie   účinky léků   MeSH
• sluchové evokované potenciály * účinky léků   MeSH
• tělesná teplota fyziologie   MeSH
• zvířata MeSH
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• morčata MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH