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3. Does exogenous melatonin influence the free radicals metabolism and pain sensation in rat?

Creator:
Pekárková, I., Parara, S., Václav Holeček, Stopka, P., Ladislav Trefil, Jaroslav Racek, and Richard Rokyta
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Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, melatonin, oxidační stres, bolest, stres (fyziologie), volné radikály, oxidative stress, pain, stress (physiology), free radicals, 14, and 612
Language:
English
Description:
Melatonin has been shown to play a role in antioxidative defence. We therefore studied its effect on oxidative damage to the rat cerebral cortex evoked by painful stimulation and immobilization-induced stress. Moreover, the effect of melatonin on chronic pain perception was examined. Rats were injected with either a high dose of melatonin (100 mg/kg i.p.) or a vehicle for five days and were subjected to painful stimulation or immobilization stress 30 min after the treatment. To determine the degree of oxidative stress, the levels of free radicals, thiobarbituric acid reactive substances (TBARS) as indicators of lipid peroxidation and glutathione peroxidase (GSHPx) were estimated in somatosensory cortex. Pain perception was measured by the tail-flick and plantar test. Melatonin reduced the level of TBARS previously increased by painful stimulation. Melatonin also exhibited a slight analgesic effect in those animals exposed to painful stimulation but its role in free radical scavenging did not contribute to this effect., I. Pekárková, S. Parara, V. Holeček, P. Stopka, L. Trefil, J. Racek, R. Rokyta., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

4. Electrophysiological identification of tonic and phasic neurons in sensory dorsal root ganglion and their distinct implications inflammatory pain

Creator:
Yu, Y.-Q., Chen, X.-F., Yang, Y., Yang, F., and Chen, J.
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Subject:
Fyziologie člověka a srovnávací fyziologie, bolest, pain, action potential, dorsal root ganglion, tonic neuron, phasic neuron, 14, and 612
Language:
English
Description:
In the mammalian autonomic nervous system, tonic and phasic neurons can be differentiated on firing patterns in response to long depolarizing current pulse. However, the similar firing patterns in the somatic primary sensory neurons and their functional significance are not well investigated. Here, we identified two types of neurons innervating somatic sensory in rat dorsal root ganglia (DRG). Tonic neurons fire action potentials (APs) in an intensity-dependent manner, whereas phasic neurons typically generate only one AP firing at the onset of stimulation regardless of intensity. Combining retrograde labeling of somatic DRG neurons with fluorescent tracer DiI, we further find that these neurons demonstrate distinct changes under inflammatory pain states induced by complete Freund’s adjuvant (CFA) or bee venom toxin melittin. In tonic neurons, CFA and melittin treatments significantly decrease rheobase and AP durations (depolarization and repolarization), enhance amplitudes of overshoot and afterhyperpolarization (AHP), and increase the number of evoked action potentials. In phasic neurons, however, the same inflammation treatments cause fewer changes in these electrophysiological parameters except for the increased overshoot and decreased AP durations. In the present study, we find that tonic neurons are more hyperexcitable than phasic neurons after peripheral noxious inflammatory stimulation. The results indicate the distinct contributions of two types of DRG neurons in inflammatory pain., Y.-Q. Yu, X.-F. Chen, Y. Yang, F. Yang, J. Chen., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

6. Increased gene expression and production of spinal cyclooxygenase 1 and 2 during experimental osteoarthritis pain

Creator:
Michaela Procházková, Peter Zanvit, Tomáš Doležal, Ludmila Prokešová, and Miloslav Kršiak
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article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, bolest, artritida, cyklooxygenáza 2, mícha, pain, arthritis, cyclooxygenase 2, spinal cord, 14, and 612
Language:
English
Description:
Knowledge on the involvement of spinal COX-1 and COX-2 in pain due to osteoarthritis could be useful for better understanding of its pa thogenesis and therapy. In this study we have investigated a long-term pattern of expression and production of spinal COX-1 and COX-2 in the model of osteoarthritis induced in rats by injection of monoiodoacetate (MIA) into the knee joint. MIA injection produced thermal hyperalgesia (assessed by the plantar test) and tactile allodynia (measured with von Frey hairs). The pain measures reached maximum on the 5th day, then re mained relatively stable. The expression of spinal COX-2 mR NA reached maximum on day 5 (5.2 times; P<0.001) and remain ed increased until day 31 (4.9 times; P<0.001). Expression of spinal COX-1 mRNA increased gradually reaching maximum on the day 31 (4.5 times; P<0.001) when the relative expression of both genes was almost equal. The production of both proteins was almost similar at the beginning of the experiment. The highest production of COX-2 protein was observed on day 5 after the induction of osteoarthritis (increased 3.9 times). The levels of COX-1 protein increased gradually with maximum on day 31 (3.4 times). The present findings indicate that not only expression of COX-2 mRNA but also that of COX-1 mRNA is significantly increased in the spine during osteoarthritis pain. Thus, in contrast to inflammatory pain, the upregulation of spinal COX-1 may be important in osteoarthritis pain., M. Procházková, P. Zanvit, T. Doležal, L. Prokešová, M. Kršiak., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

7. OPRM1 and ABCB1 polymorphisms and their effect on postoperative pain relief with piritramide

Creator:
Bartošová, O., Ondřej Polanecký, František Perlík, Svatopluk Adámek, and Ondřej Slanař
Format:
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Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, polymorfismus, bolest, polymorphism, pain, OPRM1, ABCB1, piritramide, single nucleotide polymorphism, acute pain, patient-controlled analgesia, 14, and 612
Language:
English
Description:
Genetic factors may contribute to the differential response to opioids. The aim of this study was to evaluate the association between polymorphisms of μ1-opioid receptor gene OPRM1 (rs1799971), and P-glycoprotein transporter gene ABCB1 (rs1045642, rs2032582), and piritramide efficacy under postoperative patient-controlled analgesia (PCA). In 51 patients, OPRM1 variant was associated with decreased efficacy in early postoperative period evidenced by sum of pain intensity difference in the 0-6 h postoperative period (SPID0-6), (F=3.27, p=0.029). Mean (SD) SPID0-6 was observed in the 118AA genotype 22.9 (6.1) mm, which was significantly higher from the 118GG genotype 10.0 (4.4) mm, p=0.006. The lowest cumulative dose was recorded in 118AA genotype 19.1 (9.8) mg, which was significantly less than in the 118GG genotype group 36.6 (6.1) mg, p=0.017. Opioid-induced adverse effects were observed in 11, 30, and 100 % of patients in 118AA, 118AG, and 118GG genotype groups, respectively (p<0.05). Piritramide efficacy and safety was not significantly affected by ABCB1 (rs1045642, rs2032582) polymorphisms. Variant OPRM1 118G allele is associated with decreased acute postoperative pain relief after piritramide. Decreased efficacy leads to higher drug consumption under PCA settings, which however, does not fully compensate insufficient pain relief, but increases incidence of adverse effects., O. Bartošová, O. Polanecký, F. Perlík, S. Adámek, O. Slanař., and Obsahuje bibliografii
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

8. Parvalbumin and TRPV1 receptor expression in dorsal root ganglion neurons after acute peripheral inflammation

Creator:
Gisela Zachařová and Jiří Paleček
Format:
print
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, bolest, artritida, physiology, pain, arthritis, dorsal root ganglion neurons (DRG), caregeenan, 14, and 612
Language:
English
Description:
Expression of parvalbumin (PV) and transient receptor potential vanilloid (TRPV1) receptors in the lumbar dorsal root ganglion neurons (DRG) was evaluated in control animals and in rats after acute carageenan-induced knee joint inflammation. PV is a calcium binding protein that acts as a calcium buffer, affects intracellular calcium homeostasis and may thus influence signal transduction and synaptic transmission. TRPV1 receptors are viewed as molecular integrators of nociceptive stimuli and modulate spinal cord synaptic transmission beside their function in the peripheral nerve endings. In naive rats, 13 % of the L4 DRG neurons had PV immunopositivity (PV+) and 36 % expressed TRPV1 receptors (TRPV1+). The soma of the PV+ neurons was of medium to large size, while the TRPV1 receptors were expressed in small diameter neurons. The co-localization of the PV and TRPV1 immunoreactivity was minimal (0.2 %). There was no significant change in the PV+ (11 %), TRPV1+ (42 %) and PV+TRPV1+ (0.25 %) expression, or shift in the neuronal size distribution 28 h after the unilateral peripheral inflammation, both when compared to controls and when ipsilateral to contralateral sides were evaluated. Thus under the given experimental conditions, no change in somatic TRPV1 receptors and PV expression in L4 DRG neurons was found., G. Zachařová, J. Paleček., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

9. Repetitive transcranial magnetic stimulation in the treatment of chronic orofacial pain

Creator:
Jitka Fricová, Monika Klírová, Václav Masopust, Novák, T., Vérebová, K., and Richard Rokyta
Format:
print
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, orofaciální oblast, bolest, orofacial region, pain, rTMS 10, 20 Hz, Orofacial pain, 14, and 612
Language:
English
Description:
Repetitive transcranial magnetic stimulation (rTMS) is non-invasive neuromodulation method. We applied rTMS for the treatment of farmacoresistant chronic orofacial pain. We compared the effect of 10 Hz an d 20 Hz stimulation. The study included 23 patients for 20 Hz stimulation and 36 patients for 10 Hz stimulation with pharmacoth erapy resistant chronic facial pain aged 33-65 years with pain duration of at least 6 months. Monitoring of treatment effects was performed within 15 minutes of each rTMS application (days 1-5) and finally stimulation (active vs. sham coil). If compared with data with 10 Hz rTMS study (n=36) and with 20 Hz rTMS (n=23) trials using a parallel design. Only the results obtained in a series of five rTMS treatments in the first step (active n=24, sham n=12), that 20 Hz frequency rTMS using a higher intensity (95 % of motor threshold) to be equally effective relative to VAS (Visual analogue scale) and QST (quantitative sensory testing). In conclusions, the better results with the relief of orofacial pain were obtained with 20 Hz stimulation if compared with 10 Hz stimulation. It was proved with subjective (VAS) and object ive evaluation (QST). rTMS can be used in the treatment of chronic intractable pain., J. Fricová ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

10. Role of L-DOPA in spinal nociceptive reflex activity: higher sensitivity of Aδ versus C fibre-evoked nociceptive reflexes to L-DOPA

Creator:
Schomburg, E. D., Bibaj, P., and Steffens, H.
Format:
print
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, bolest, mícha, pain, spinal cord, L-DOPA, TTX, Aδ-fibres, nociceptive reflexes, 14, and 612
Language:
English
Description:
The role of L-DOPA in spinal nociceptive reflex activity has been re-evaluated. In high spinal ca ts, with supraspinal loops being excluded, the onset of reflex facilitation induced by noxious radiant heat is delayed after injection of L-DOPA by 4 to 10 s, i.e. the early component of nociceptive reflex facilitation is blocked, while the late component persisted. Further investigations have shown that the early component of reflex facilitation induced by noxious radiant heat is mediated by Aδ-fibres and the late component by C-fibres. Therefore, it can be assumed that L-DOPA, like opioids, preferentially blocks the transmission in nociceptive reflex pathways from Aδ-fibres., E. D. Schomburg, P. Dibaj, H. Steffens., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public