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The role of ghrelin in modulation of neuropathic pain
Komárková, Lucia ; Vaculín, Šimon (advisor) ; Franěk, Miloslav (referee)
We are still unable to effectively suppress neuropathic pain, therefore it remains a serious problem. Ghrelin, the orexigenic hormone released by enteroendocrine stomach cells, could contribute to alleviation of the neuropathic pain by its antinociceptive effect. Previous studies have shown that ghrelin prevents development of nociceptive symptoms of neuropathic pain. The aim of our study was to determine whether chronic administration of ghrelin will affect the already fully developed neuropathic pain and differentiate its antinociceptive and analgesic effect. We used a model of chronic constriction injury of the sciatic nerve. We have proven that ghrelin suppressed the already developed thermal and mechanical hyperalgesia, so ghrelin not only prevents the development, but also suppresses the already developed nociceptive symptoms. However analgesia test showed that ghrelin did not affect the temperature preference, neither did induce the place preference. We suppose that ghrelin does not cause analgesia in neuropathic pain and its antinociceptive effect could be caused by anti- inflammatory or neuroprotective action. Key words: Ghrelin, neuropathic pain, chronic constriction injury, preference methods
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Comparison of reflex-based and operant methods when evaluating effects of treatment on pain in experimetnal models
Panušková, Kristýna ; Vaculín, Šimon (advisor) ; Šustková, Magdaléna (referee)
Pharmacological treatment of neuropathic pain is still insufficient. Methylphenidate, a psychostimulant that increases the dopamine and noradrenaline levels, is commonly used for treating ADHD. There have been reports of changes in patients pain thresholds by ADHD patients treated with methylphenidate. The aim of the study is to examine if methylphenidate can affect peripheral neuropathic pain. Neuropathic pain has been modelled on laboratory rats by chronic constriction of the ischiatic nerve. The effect of methylphenidate on the evoked pain component was evaluated on control animals and on animals with neuropathic pain using reflex (plantar test, vonFrey test) and operanting test (thermal place preference). The effect of methylphenidate on the spontaneous components of pain was evaluated using the methods of conditioned place preference. This study has proven that methylphenidate in an applicable dose of 1 mg/kg has an antialodynic effect but does not act antinociceptively. This study further confirms that methylphenidate in low doses does not act as attractant and has no effect on spontaneous pain. The last part of the study compares the different methods for pain measurement and comes to the conclusion that the plantar test is not an adequate method for evaluating the effect of analgesics...
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Ongoing pain in animal models of neuropathic pain
Priessnerová, Denisa ; Vaculín, Šimon (advisor) ; Honc, Ondřej (referee)
Although spontaneous pain is a global problem, there is still no effective treatment. Constructive research started only 40 years ago. Research based on pain mechanisms and potential treatment has been done on animal models of neuropathic pain. This thesis is focused on animal models, which could be either induced by chronic constriction of the sciatic nerve (CCI) or spinal nerve ligation (SNL). Both models should induce spontaneous, ongoing pain along with evoked pain (allodynia and hyperalgesia). Tests, made on these models, are based on detection and measurement of spontaneous pain, while not using an external stimulus. The outcome of the tests is not always effective. Most of the time, they do not evince signs of spontaneous pain. These tests are also less effective and fewer in numbers compared to those using external stimulus. The goal of this thesis was to analyze all the research including spontaneous and ongoing pain in CCI and SNL models. It was important to focus on certain methods that do not use external stimulus during testing. PubMed database was used for searching articles. The most common words searched were "spontaneous" and "ongoing". Found articles were evaluated and searched for methods indicating and measuring spontaneous pain without an external stimulus. Most of the methods...
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Reflexive measurement of thermal hyperalgesia in neuropathic pain model
Panušková, Kristýna ; Vaculín, Šimon (advisor) ; Adámek, Pavel (referee)
Neuropathic pain substantially decreases a person's quality of life and thus far nothing has been invented that can alleviate that pain. One of the most commonly used model for induced peripheral neuropathic pain in animals is chronic constriction of the sciatic nerve. Experimental induction of neuropathic pain in rats is verified by reflexive measurement. Reflexive measuring can also be used to test the efficacy of the experimental treatment. The large range of reflexive tests that can be applied differ in terms of the stimulus used and the area of stimulation. This bachelor thesis will focus on analyses of the thermal pain threshold after a chronic constriction injury (CCI) to the sciatic nerve. Articles used in this thesis were found in the electronic database PUBMED/MEDLINE by searching for the terms "chronic constriction injury" and "pain threshold" for last 10 years. Articles related to the thermal pain threshold of rats after CCI were ranked according to the prestige of magazine that published them and ten articles with a quartile of 1 were selected for further analyses. The tests used, control methods during the study, measuring interval, measurement before operation and pain threshold values were extracted from these articles. Measurement of behavioral signs is not unified. The Hargreaves...
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The role of ghrelin in modulation of neuropathic pain
Komárková, Lucia ; Vaculín, Šimon (advisor) ; Franěk, Miloslav (referee)
We are still unable to effectively suppress neuropathic pain, therefore it remains a serious problem. Ghrelin, the orexigenic hormone released by enteroendocrine stomach cells, could contribute to alleviation of the neuropathic pain by its antinociceptive effect. Previous studies have shown that ghrelin prevents development of nociceptive symptoms of neuropathic pain. The aim of our study was to determine whether chronic administration of ghrelin will affect the already fully developed neuropathic pain and differentiate its antinociceptive and analgesic effect. We used a model of chronic constriction injury of the sciatic nerve. We have proven that ghrelin suppressed the already developed thermal and mechanical hyperalgesia, so ghrelin not only prevents the development, but also suppresses the already developed nociceptive symptoms. However analgesia test showed that ghrelin did not affect the temperature preference, neither did induce the place preference. We suppose that ghrelin does not cause analgesia in neuropathic pain and its antinociceptive effect could be caused by anti- inflammatory or neuroprotective action. Key words: Ghrelin, neuropathic pain, chronic constriction injury, preference methods
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