The effect of median nerve mobilization on two point discrimination.

[Purpose] Two-point discrimination (TPD) is expressed as the minimum distance at which two mechanical stimuli applied simultaneously to the skin can be perceived as two separate points. The aim of this study was to investigate the effect of median nerve mobilization on TPD in healthy adults. [Participants and Methods] This study included 120 healthy adults. Participants were randomized according to their gender into the Neural Mobilization Group (NMG) and Control Group (CG). Demographic data of the participants (gender, age, height, weight, BMI, smoking) were recorded and TPD measurement was performed with baseline aesthesiometer on the palm with distal phalanges of the thumb, index and middle finger on the right-left hand. After the baseline TPD test, participants in the NMG performed Median Nerve Mobilization for 14 days. Measurements were taken before and after training. [Results] A statistically significant difference was found in all other measurements in both groups, except for the right and left palm TPD measurements in the control group. [Conclusion] It is thought that it would be beneficial to investigate the healing effects of the neural mobilization applications, which include all parts of the nerve line in disease conditions.

Proconvulsant Effect of Papaverine on Penicillin-Induced Epileptiform Activity in Rats.

AIM: Papaverine is a vasodilator agent that is an opium alkaloid. It exhibits its effects by inhibiting the phosphodiesterase enzyme. Papaverine administration is widely used to avoid symptomatic vasospasm after subarachnoid hemorrhage. We aimed, in this research, to study the effects of papaverine on the epileptic discharges stimulated by penicillin. MATERIAL AND METHODS: Adult female Wistar rats (220±30 g) were included in this research (n=30). Rats were anesthetized with urethane (1.25 g/kg) and then the left cerebral cortex was reached by opening a burr hole with a drill. Penicillin G sodium salt (500 IU)(200 IU/1 µl) was injected into the left lateral ventricle to produce epileptiform activity. Thirty minutes before penicillin G sodium injection, papaverine was administered at doses of 5, 10, 20 or 40 mg/kg intraperitoneally. RESULTS: There was no significant difference in spike frequency between the control group and the groups given 5 mg/kg, 10 mg/ kg or 40 mg/kg papaverine, while 20 mg/kg papaverine significantly increased the spike frequency (p < 0.05). CONCLUSION: Papaverine augments the epileptiform activity produced by penicillin injection. It is important to remember that papaverine might induce convulsions in patients who have epilepsy. More research is required to understand the mechanisms of the proconvulsant influence of papaverine in epilepsy.

Effects of spermine and the passive avoidance learning (PAL) following cerebral ischemia in chicks: Association with neuroprotection of pyramidal cells.

The aim of this study is to investigate the effects of spermine and the passive avoidance learning on hippocampus following transient cerebral ischemia in the chicks. The study is composed of the pure control (CG), sham (SG) and experimental groups (n=20). Experimental groups (ischemia group, IG and ischemia-spermine group, ISG) were exposed to ischemia for 20min whereas the SG was exposed to sham operation and CG group was not exposed to any operation. Passive avoidance learning (PAL) was applied to the half number of the subjects in each group. Both before and after 7days from the ischemia, operated animals were taken to PAL and then they were sacrificed. Total numbers of neurons in the hippocampus were stereologically estimated using Cresyl violet stained sections. We detected that number of neurons was increased following PAL and especially spermine treatment. According to our results, we suggested that spermine may reduce the deleterious effects of the ischemia by causing to increase in the neuronal number and so, it may be slightly supportive to the PAL.

Protective effects of melatonin and omega-3 on the hippocampus and the cerebellum of adult Wistar albino rats exposed to electromagnetic fields.

The purpose of the study was to investigate the effects of pulsed digital electromagnetic radiation emitted by mobile phones on the central nervous system of the adult Wistar albino rats. The study evaluated structural and functional impacts of four treatment arms: electromagnetic field (EMF) exposed; EMF exposed + melatonin treated group (EMF + Mel); EMF exposed + omega-3 (ω3) treated group (EMF + ω3); and control group (Cont). The 12-weeks-old rats were exposed to 900 MHz EMF for 60 min/day (4:00-5:00 p.m.) for 15 days. Stereological, biochemical and electrophysiological techniques were applied to evaluate protective effects of Mel and ω3. Significant cell loss in the CA1 and CA2 regions of hippocampus were observed in the EMF compared to other groups (p < 0.01). In the CA3 region of the EMF + ω3, a significant cell increase was found compared to other groups (p < 0.01). Granular cell loss was observed in the dentate gyrus of the EMF compared to the Cont (p < 0.01). EMF + ω3 has more granular cells in the cerebellum than the Cont, EMF + Mel (p < 0.01). Significant Purkinje cell loss was found in the cerebellum of EMF group compared to the other (p < 0.01). EMF + Mel and EMF + ω3 showed the same protection compared to the Cont (p > 0.05). The passive avoidance test showed that entrance latency into the dark compartment was significantly shorter in the EMF (p < 0.05). Additionally, EMF had a higher serum enzyme activity than the other groups (p < 0.01). In conclusion, our analyses confirm that EMF may lead to cellular damage in the hippocampus and the cerebellum, and that Mel and ω3 may have neuroprotective effects.

Effect of levetiracetam on penicillin induced epileptic activity in rats.

The aim of this study was to investigate the effects of levetiracetam (LEV) on penicillin-induced epileptiform activity in rats. Penicillin was applied intracerebroventricularly (icv) at a dose of 500 IU to induce epileptiform activity. LEV was given intraperitoneally (ip) at doses of 20, 40, 80 mg/kg before penicillin injection. This agent reduced epileptiform activity by decreasing spike frequencies. The mean spike frequencies decreased significantly in all the LEV treated groups. There was no significant change in the spike amplitudes of the LEV groups compared with the control group. 40 mg/kg of LEV was determined as the most effective dose on reducing epileptiform activity. The results of this study suggest that LEV is an effective antiepileptic agent in penicillin-induced epilepsy.

Influence of carbenoxolone on the anticonvulsant efficacy of phenytoin in pentylenetetrazole kindled rats.

Abnormal synchronized neuronal discharges mediated by gap junctions have an important role in epileptic seizures. The analysis of anticonvulsant drugs acting on gap junctions is still a priority in epilepsy research. Therefore, the present study was designed to investigate the effect of carbenoxolone, a gap junction blocker, on the anticonvulsant efficacy of phenytoin in pentylenetetrazole kindled rats. Male Wistar albino rats, 14 weeks of age, were used. In the first step of the study, animals were given PTZ 35 mg/kg intraperitoneally (i.p.) three times a week until kindling was produced. Then, indwelling screw electrodes - allowing EEG monitoring of conscious rats - were implanted into the crania of the kindled rats. In this way, we were able to record EEG activity and evaluate seizure stage at the same time. In the second step of the study, the interaction between carbenoxolone (40 mg/kg i.p.) and phenytoin (60 mg/kg, i.p.) was investigated. The data analysis was performed using a one-way ANOVA with LSD post-hoc test. Total spike number and the generalized seizure duration were reduced in the carbenoxolone treated group compared to the PTZ group. Phenytoin decreased generalized seizure duration, total spike number and seizure severity score. Carbenoxolone and phenytoin have anti-seizure effects in PTZ kindled rats. There was no significant difference between the carbenoxolone + phenytoin combination and phenytoin in terms of generalized seizure duration, total spike number and seizure stage. The results indicate that carbenoxolone combined with phenytoin is not more effective than the use of these drugs alone.

The interactions of nitric oxide and acetylcholine on penicillin-induced epilepsy in rats.

The aim of this study was to investigate the interaction between nitric oxide (NO) and acetylcholine (ACh) in penicillin-induced experimental epilepsy. Adult male Wistar rats weighing 220 ± 35 g were used in the experiments. The epileptiform activity was induced by microinjection of penicillin (200 IU/1 µl) into the left sensorymotor cortex. Electrocorticogram was recorded by using Ag/AgCl ball electrodes. Sodium nitroprusside (SNP), a NO donor, given intracortically 30 min after penicillin significantly reduced the spike frequency whereas ACh increased the epileptiform activity for 5 min. Atropine, an antagonist for muscarinic receptors, was given intracortically 30 min after penicillin and did not significantly affect epileptiform activity for 30 min. SNP given after atropine significantly suppressed the epileptiform activity. ACh given 10 min after Nω-nitro-L: -arginine methyl ester (L-NAME), a nonspecific nitric oxide synthase inhibitor, did not have a significant effect on spike frequency. When ACh and SNP were administered together, penicillin induced epileptiform activity and spike frequency were significantly suppressed from the 10th minute onwards. It can be concluded that ACh increases the penicillin-induced epileptiform activity while co-administration of ACh and SNP produces a potent anticonvulsant effect as compared to SNP alone.

The interactions of nitric oxide and adenosine on penicillin-induced epileptiform activity in rats.

In this study, the influence of nitric oxide (NO) and adenosine systems on penicillin-induced epileptiform activity was examined in rats. NO donor, sodium nitroprusside (SNP, 50 micrograms per rat, i.c.v.) reduced the frequency but not the amplitude of epileptiform discharges. Non-selective NOS inhibitor, N-omega-nitro-L-arginine methyl ester (L-NAME, 100 micrograms per rat, i.c.v.) practically did not exert any effect on the spike frequency and amplitude. Adenosine (100 micrograms per rat, i.c.) reduced spike frequency but not the amplitude, whereas theophylline (100 micrograms per rat, i.c.v.) increased the mean spike frequency and amplitude of penicillin-induced epileptiform discharges. Co-injection of theophylline and L-NAME did not cause a further increase in the epileptiform activity compared with theophylline. When NO production was blocked with L-NAME, the inhibitory effects of adenosine were lost. The obtained results suggest that NO and adenosine may decrease penicillin-induced epileptiform activity in rats and that NO, at least in part, may mediate the anticonvulsant effect of adenosine.

Nitric oxide synthase inhibitors protect cerebellar Purkinje cells from zinc-induced cell loss in adult rat.

Zinc is an important trace element in biological systems; however, excessive extracellular zinc could lead to neuronal cell death following ischemia, seizures, and brain trauma. In this study, we investigated whether the intracortical injection of zinc sulphate (200 µg/kg, i.c.) changes total number of Purkinje cells in the cerebellum and whether different types nitric oxide synthase inhibitors, N-(G)-nitro-L-arginine methyl ester (L-NAME), N(omega)-nitro-L-arginine (L-NNA), aminoguanidine and 7-nitroindazole (7-NI), have protective effects against zinc neurotoxicity in Wistar albino rats. Animals were divided into 6 groups: control, zinc, zinc+L-NAME (100 mg/kg, i.p.), zinc+L-NNA (100 mg/kg, i.p.), zinc+7-NI (100 mg/kg, i.p.) and zinc+aminoguanidine (100 mg/kg, i.p.) groups. Total number of Purkinje cells in the cerebellum was estimated using unbiased stereological technique as 318,947 ± 20,549, 123,483 ± 23,762, 206,537 ± 43,128, 178,135 ± 26,635, 193,148 ± 46,104 and 212,910 ± 26,399 in the control, zinc, zinc+L-NAME, zinc+L-NNA, zinc+7-NI and zinc+aminoguanidine groups, respectively (mean ± SD). The number of Purkinje cells in zinc group was significantly lower than that of the other groups (P<0.001). It was found that the nitric oxide synthase inhibitors have neuroprotective effect against zinc neurotoxicity on Purkinje cells. These data show that the inhibition of the nitric oxide synthase could prevent some of the deleterious effects of zinc on Purkinje cells.

Detailed spectral profile analysis of penicillin-induced epileptiform activity in anesthetized rats.

Penicillin model is a widely used experimental model for epilepsy research. In the present study we aimed to portray a detailed spectral analysis of penicillin-induced epileptiform activity in comparison with basal brain activity in anesthetized Wistar rats. Male Wistar rats were anesthetized with i.p. urethane and connected to an electrocorticogram setup. After a short period of basal activity recording, epileptic focus was induced by injecting 400IU/2 microl penicillin-G potassium into the left lateral ventricle while the cortical activity was continuously recorded. Basal activity, latent period and the penicillin-induced epileptiform activity periods were then analyzed using both conventional methods and spectral analysis. Spectral analyses were conducted by dividing the whole spectrum into different frequency bands including delta, theta (slow and fast), alpha-sigma, beta (1 and 2) and gamma (1 and 2) bands. Our results show that the most affected frequency bands were delta, theta, beta-2 and gamma-2 bands during the epileptiform activity and there were marked differences in terms of spectral densities between three investigated episodes (basal activity, latent period and epileptiform activity). Our results may help to analyze novel data obtained using similar experimental models and the simple analysis method described here can be used in similar studies to investigate the basic neuronal mechanism of this or other types of experimental epilepsies.

Extracorporeal shockwave application to the distal femur of rabbits diminishes the number of neurons immunoreactive for substance P in dorsal root ganglia L5.

Application of extracorporeal shockwaves to the musculoskeletal system can induce long-term analgesia in the treatment of chronic painful diseases such as calcifying tendonitis of the shoulder, tennis elbow and chronic plantar fasciitis. However, the molecular and cellular mechanisms underlying this phenomenon are largely unknown. Recently it was shown that application of extracorporeal shockwaves to the distal femur of rabbits can lead to reduced concentration of substance P in the shockwaves' focal zone. In the present study we investigated the impact of extracorporeal shockwaves on the production of substance P within dorsal root ganglia in vivo. High-energy shockwaves were applied to the ventral side of the right distal femur of rabbits. After six weeks, the dorsal root ganglia L5 to L7 were investigated with high-precision design-based stereology. The application of extracorporeal shockwaves caused a statistically significant decrease in the mean number of neurons immunoreactive for substance P within the dorsal root ganglion L5 of the treated side compared with the untreated side, without affecting the total number of neurons within this dorsal root ganglion. No effect was observed in the dorsal root ganglia L6 and L7, respectively. These data might further contribute to our understanding of the molecular and cellular mechanisms in the induction of long-term analgesia by extracorporeal shockwave application to the musculoskeletal system.

Anticonvulsant effects of focal and intracerebroventricular adenosine on penicillin-induced epileptiform activity in rats.

Adenosine has potent anticonvulsant effects on various models of experimental epilepsy. In the present study, we examined the effects of focal and intracerebroventricular (i.c.v.) adenosine on penicillin-induced epileptiform activity in Wistar rats. The effects of theophylline, a non-selective adenosine receptor antagonist, were also researched. The recordings of electrocorticogram (ECoG) were carried out by using a data acquisition system, under urethane anesthesia. Adenosine was given in doses of 1, 10 and 100 microg/rat via focal and i.c.v. 30 min after penicillin administration. Theophylline was injected in doses of 1, 10 and 100 microg/rat by i.c.v. too. Adenosine administration significantly decreased the spike frequency while theophylline increased. Focal adenosine is more effective than i.c.v. adenosine. 100 microg adenosine is an effective dose that causes a decrease in epileptiform activity during experiments. We also demonstrated that 100 microg theophylline significantly increased epileptiform activity. Our findings suggest that focal adenosine is more effective than i.c.v. adenosine on epileptiform activity.

Anticonvulsant effects of melatonin on penicillin-induced epileptiform activity in rats.

In the present study, we investigated the effects of melatonin on penicillin-induced epileptiform activity in female Wistar rats. The left cerebral cortex was exposed by craniotomy under urethane anesthesia for the induction of epilepsy by intracortical microinjection of penicillin (200 IU) into the left sensorimotor cortex. The epileptiform activity was analyzed by electrocorticogram (ECoG). Ten minutes before the penicillin injection, 20, 40 or 80 microg of melatonin was administered intracerebroventricularly and ECoG was monitored for 1 h. Forty or 80 microg of melatonin significantly increased the latency to epileptiform activity. Furthermore, melatonin significantly decreased the frequency of spike and spike-wave activity, whereas the amplitude of spikes remained unchanged. In conclusion, data obtained from the present study suggest that melatonin suppresses penicillin-induced epileptiform activity, and it may be an endogenous anticonvulsant.

Effects of nitric oxide on passive avoidance learning in rats.

To investigate the effects of nitric oxide (NO) on passive avoidance learning, L-NAME, D-NAME, and L-arginine were administered i.p. 30 min prior to learning trial; the effects of these substances were tested 24 h later using a passive avoidance apparatus in rats. To reveal the effect of NO on consolidation of acquired memory, L-NAME, D-NAME, and L-arginine were administered i.p. immediately after learning trials and animals were tested 24 h later. Effect of NO on retention was also investigated by injecting L-NAME, D-NAME, and L-arginine (same dosages) 30 min prior to 24 h testing (retrieval). L-NAME administered 30 min before and 24 h after learning trial significantly decreased the avoidance latency but there was no significant effect on consolidation. L-Arginine appeared to enhance the retention of acquired memory significantly, whereas D-NAME had no effect on any testing regime. The results suggest that NO may be involved in learning and retention of passive avoidance.