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Öğe Coenzyme Q(10) and alpha-lipoic acid supplementation in diabetic rats: Conduction velocity distributions(PROUS SCIENCE, SAU-THOMSON REUTERS, 2008) Ayaz, Murat; Tuncer, Seckin; Okudan, Nilsel; Gokbel, HakkiDiabetic neuropathies are a family of nerve disorders caused by diabetes. Patients with diabetes can develop nerve problems at any tune, but the longer a person has diabetes the greater the risk. This study aims to investigate diabetes- and coenzyme Q(10) (CoQ(10)) or alpha-lipoic acid (ALA) supplementation-induced changes in the conduction velocity (CV) distributions of rat sciatic nerve fibers. Sciatic nerve compound action potentials (CAPs) were recorded by suction electrode and CV distributions by the collision technique. Diabetes resulted in a significant increase in time to peak, rheobase and chronaxie values of these CAP waveforms, whereas the maximum depolarization, area, kinetics and CVs of both fast and slow nerve fiber groups were found to be decreased, Coenzyme Q(10) (CoQ(10)) supplementation was found to have some positive effect on the diabetes-induced alterations. CoQ(10) supplementation induced positive changes mainly, in the area and fall-down phase of the kinetics of CAP waveforms, as well as rheobase. chronaxie and speed of the intermediately conducting groups (congruent to 40 m/s). alpha-Lipoic acid (ALA) supplementation did not produce statistically significant effects. This stud), has shown for the first tune that diabetes induces a shift of actively contributing nerve fibers toward slower CVs(10) and supplementation with CoQ(10) not only stopped this shift but also tended to restore velocities toward those of the age-matched control group. In addition to its effects on mitochondrial alterations, these positive effects of CoQ(10) on diabetic neuropathy) can be attributed to its antioxidant activity Copyright 2008 Prous Science, S.A.U. or its licensors. All rights reserved.Öğe AN EARLY DIAGNOSTIC TOOL FOR DIABETIC NEUROPATHY: CONDUCTION VELOCITY DISTRIBUTION(WILEY, 2011) Tuncer, Seckin; Dalkilic, Nizamettin; Esen, Haci Hasan; Avunduk, Mustafa CihatDiabetes is a metabolic disorder that. affects much of the human population. As a secondary complication, diabetic neuropathy causes time-dependent damage to peripheral nerves. In this study, experimental diabetes was induced by streptozotocin (STZ; 50 mg/kg intraperitoneally) in rats. Diabetic animals were grouped into those with 2 or 4 weeks of diabetes, whereas a control group received only the STZ vehicle (0.1 M citrate). Sciatic nerves were dissected, and compound action potentials (CAPS) were recorded. Results deduced by conventional calculation carried less information when compared with conduction velocity distribution (CVD) obtained by a computer-based mathematical model. Using the conventional approach, statistically significant changes were first seen in the fourth week of diabetes, whereas results deduced by CVD measurement could be seen in the second week. Consequently, the CVD calculation provides more information for the early diagnosis of neuropathies compared with classical conduction velocity measurements. Muscle Nerve 43: 237-244, 2011Öğe The Effect of Tramadol on the Rat Sciatic Nerve Conduction: A Numerical Analysis and Conduction Velocity Distribution Study(PHARMACEUTICAL SOC JAPAN, 2009) Dalkilic, Nizamettin; Tuncer, Seckin; Bariskaner, Hulagu; Kiziltanc, ErhanThe aim of this study was to document the effect of tramadol as an opioid on individual fibers of rat sciatic nerve. To accomplish this objective, compound action potentials (CAPs) were recorded from isolated nerves treated with tramadol from five different concentration levels. Then recorded CAPs and the control group were analyzed by numerical methods namely Conduction Velocity Distribution (CVD) and Fast Fourier Transform (FFT). The results show that the area under CAP and the time derivative of CAP curves decreases, and the excitability of the nerve trunk falls as well (rheobase and chronaxie increases) with increasing tramadol concentration. CVD deduced by model study was divided into subgroups as SLOW (8-26 m/s), MODERATE (26-44 m/s), MEDIUM (44-60 m/s) and FAST (60-78 m/s). The decrement in percentage relative contribution of these conduction velocity groups starts with a concentration of 0.25 mM tramadol, especially in the subgroup named FAST. The power spectrum shifts from higher frequency region to lower frequency region as the tramadol concentration increases. These findings show that fast conducting fibers are more susceptible to tramadol than medium and moderate groups and tramadol possibly acts on channel activity rather than passive properties (such as space and time constant) of nerve fibers.Öğe Gender-dependent effects of selenite on the perfused rat heart - A toxicological study(HUMANA PRESS INC, 2007) Ayaz, Murat; Dalkilic, Nizamettin; Bariskaner, Hulagu; Tuncer, Seckin; Demirel, IlhamiGender differences are related to the manner in which the heart responds to chronic and acute stress conditions of physiological and pathological nature. Depending on dose, sodium selenite acts as an antioxidant proven to have beneficial effects in several pathological conditions G. Drasch, J. Schopfer, and G. N. Schrauzer, Selenium/cadmium ratios in human prostates: indicators of prostate cancer risk of smokers and nonsmokers, and relevance to the cancer protective effects of selenium, Biol. Trace Element Res. 103(2), 103-107 (2005); R. G. Kasseroller and G. N. Schrauzer, Treatment of secondary lymphedema of the arm with physical decongestive therapy and sodium selenite: a review, Am. J. Ther. 7(4), 273-279 (2000); G. N. Schrauzer, Anticarcinogenic effects. of selenium, Cell. Mol. Life Sci. 57(13-14),1864-1873 (2000); I. S. Palmer and O. E. Olson, Relative toxicities of selenite and selenate in the drinking water of rats, J. Nutr. 104(3), 306-314 (1974). To date, little is known about the gender-dependent direct effects of toxic doses of selenite on electrophysiology of the cardiovascular system H. A. Schroeder and M. Mitchener, Selenium and tellurium in rats: effect on growth, survival and tumors, J. Nutr. 101(11), 1531-1540 (1971); G. N. Schrauzer, The nutritional significance, metabolism and toxicology of selenomethionine, Adv. Food Nutr. Res. 47, 73-112 (2003). In the present study, the effects of in vitro toxic concentrations of sodium selenite ranging from 10(-6) M to 10(-3) M were tested on both male and female rat heart preparations. The toxic effects seen in an electrocardiogram and left ventricular pressure were dose and sex dependent atÖğe Selenium-induced changes on rat sciatic nerve fibers: Compound action potentials(PROUS SCIENCE, SA-THOMSON REUTERS, 2008) Ayaz, Murat; Dalkilic, Nizamettin; Tuncer, Seckin; Bariskaner, HulaguThe nervous system, through its important role as a communication network, governs reactions to stimuli, processes information and generates elaborate patterns of signals to control complex behaviors. Although selenium (Se) was shown to have some beneficial effects in pathological conditions, it is still a toxic element with a fairly small therapeutic window. In this study, the direct effects of Se ranging from 10(-8) to 10(-4) M were tested on rat sciatic nerve preparations. The toxicity started at 10-8 M and the degree of alterations was found to be dose-dependent. In between the measured parameters, total compound action potential area (Astart 3 70 +/- 0.16 ms x mV and A(-8) M = 3.04 +/- 0.14 ms x mV) and maximum depolarization points (MDstart = 6.70 +/- 0.22 mV and MD(-8) M = 6.04 +/- 0.18 mV) were the first to be affected from 10(-8) M. Latencies and conduction velocity distribution measurements have shown that nerve fibers having intermediate conduction velocities (20-35 m/s) are the first to be affected front this toxicity. Despite the fact that the new claims concluded the positive effects of the administrations, it is evident that the dose of supplementation must be fine-tuned to avoid possible side effects. Copyright 2008 Prous Science, S.A.U. or its licensors. All rights reserved.Öğe Sexual dependency of rat sciatic nerve fiber conduction velocity distributions(TAYLOR & FRANCIS LTD, 2007) Ayaz, Murat; Kiziltan, Erhan; Tuncer, Seckin; Dalkilic, Nizamettin; Demirel, Ilhami; Bariskaner, Hulagu; Pehlivan, FeritGender differences, either with the structural or through with hormones, dictate how the corresponding organ or organ system responses to physiological signals. Current study aims to investigate gender dependent differences in conduction related parameters of rat sciatic nerve. Compound action potentials ( CAP) were recorded via suction electrode whereas the conduction velocity distributions (CVD) were performed using the method known as collision technique in the literature. Studied CAP parameters, namely conduction velocities ( CV), area of the CAPs and time required to reach the maximum depolarization (TP) have been found significantly different for female and male rats. Detailed analyses have shown that sex dependent differences were more remarkable in the right leg responses of female and male rats. Additionally, CVDs indicate that the number of fibers having CVs between 5-30 m/s is much more in male right sciatic nerve trunk when compared to age matched female rats. The present study, for the first time clearly shows that shift in the contribution of nerve fibers to lower CVs is the main causal of the sex dependent differences seen in rat sciatic nerve fibers.
