Significant Increase In Latency Research Articles

Brainstem Evoked Auditory Responses in Neonatal Hyperbilirubinemia Infants

Jaundice is a common finding in neonates affecting 70% of term and 80% of preterm neonates during the first week of life. Objective of this study is to evaluate auditory and brainstem responses in hyperbilirubinemia infants and to see if there is any statistically significant increase in latencies of wave I and V waves with rise in bilirubin levels. In the present study we have taken 53 infants with hyperbilirubinemia>11mg% & with no other risk factors like preterm, low birth weight, birth asphyxia and age and sex matched controls who visited pediatric OPD of Bapuji Child Health Centre were evaluated using RMS EMG. EP MARK –II machine. Latencies of Waves I and V and inter-peak latency of I-V were recorded. Latency of wave V and IPL I-V were increased slightly compared to normal control subjects. Increase in the threshold leading to hearing impairment in the affected infants and complete deafness where none of the waves were recorded signify that hyperbilirubinemia is a risk factor for deafness. Since hyperbilirubinemia is a risk factor for hearing impairment, their hearing screening by BERA at the earliest and follow up will help in their earliest initiation of rehabilitation when the brain is sensitive to the development of speech & language.

Electrophysiological biomarkers of central nervous system affection in cases of chronic obstructive pulmonary disease (COPD)

BackgroundChronic obstructive pulmonary disease is associated with significant systemic abnormalities which includes systemic inflammation and neurohormonal activation that are considered the main mechanisms of the pathophysiology in systemic involvement. The aim of the present study was to detect the subclinical affection of the central nervous system in patients with stable chronic obstructive pulmonary disease.ResultsForty patients with chronic obstructive pulmonary disease were enrolled in this study and 30 healthy subjects as a control group. All patients and healthy subjects were submitted to full history taking, clinical examination, arterial blood gases, spirometry, evoked potential, and electroencephalogram. Regarding to brain stem auditory evoked potentials, there was a statistically significant increase of latency of waves numbers I, III, and V, and a statistically significant increase of interpeak latencies I–III in the COPD group when compared to the control group. On the other hand, there was a statistically significant decrease of brain stem auditory evoked potential I and V amplitudes on both sides in the COPD group when compared to the control group. In visual evoked potential, there was a statistically significant increase of latency and decrease of amplitude of P100. In addition, there was a statistically significant increase of electroencephalogram changes in the COPD group when compared to the control group (20.0% vs. 3.3%, respectively).ConclusionIn patients with chronic obstructive pulmonary disease, the central nervous system could be affected subclinically as the severity of chronic obstructive pulmonary disease increased, and the patient should be electrophysiologically monitored for early detection of nervous system affection.

Fyn-tau Ablation Modifies PTZ-Induced Seizures and Post-seizure Hallmarks of Early Epileptogenesis.

Both Fyn and tau have been associated with neuronal hyperexcitability and neurotoxicity in many tauopathies, including Alzheimer's disease (AD). Individual genetic ablation of fyn or tau appears to be protective against aberrant excitatory neuronal activities in AD and epilepsy models. It is, however, still unknown whether ablation of both Fyn and tau can likely elicit more profound anti-seizure and neuroprotective effects. Here, we show the effects of genetic deletion of Fyn and/or tau on seizure severity in response to pentylenetetrazole (PTZ)-induced seizure in mouse models and neurobiological changes 24 h post-seizures. We used Fyn KO (fyn−/−), tau KO (tau−/−), double knockout (DKO) (fyn−/−/tau−/−), and wild-type (WT) mice of the same genetic background. Both tau KO and DKO showed a significant increase in latency to convulsive seizures and significantly decreased the severity of seizures post-PTZ. Although Fyn KO did not differ significantly from WT, in response to PTZ, Fyn KO still had 36 ± 8% seizure reduction and a 30% increase in seizure latency compared to WT. Surprisingly, in contrast to WT, Fyn KO mice showed higher mortality in <20 min of seizure induction; these mice had severe hydrocephalous. None of the tau−/− and DKO died during the study. In response to PTZ, all KO groups showed a significant reduction in neurodegeneration and gliosis, in contrast to WT, which showed increased neurodegeneration [especially, parvalbumin (PV)-GABAergic interneurons] and gliosis. DKO mice had the most reduced gliosis. Immunohistochemically, phospho-tau (AT8, pS199/S202), Fyn expression, as well as Fyn-tau interaction as measured by PLA increased in WT post-PTZ. Moreover, hippocampal Western blots revealed increased levels of AT8, tyrosine phospho-tau (pY18), and phosphorylated Src tyrosine family kinases (pSFK) in PTZ-treated WT, but not in KO, compared to respective controls. Furthermore, PV interneurons were protected from PTZ-induced seizure effects in all KO mice. The levels of inwardly rectifying potassium (Kir 4.1) channels were also downregulated in astrocytes in the WT post-PTZ, while its levels did not change in KO groups. Overall, our results demonstrated the role of Fyn and tau in seizures and their impact on the mediators of early epileptogenesis in PTZ model.

Liquid Crystalline Nanoparticles for Nasal Delivery of Rosuvastatin: Implications on Therapeutic Efficacy in Management of Epilepsy.

In the present study we investigated the protective role of intranasal rosuvastatin liquid crystalline nanoparticles (Ros-LCNPs) against pentylenetetrazole (PTZ) induced seizures, increasing current electroshock (ICES) induced seizures, and PTZ-induced status epilepticus. From the dose titration study, it was evident that intranasal rosuvastatin (ROS), at lower dose, was more effective than oral and intraperitoneal ROS. The Ros-LCNPs equivalent to 5 mg/kg ROS were developed by hydrotrope method using glyceryl monooleate (GMO) as lipid phase. The high resolution TEM revealed that the formed Ros-LCNPs were cubic shaped and multivesicular with mean size of 219.15 ± 8.14 nm. The Ros-LCNPs showed entrapment efficiency of 70.30 ± 1.84% and release was found to be biphasic following Korsmeyer–Peppas kinetics. Intranasal Ros-LCNPs (5 mg/kg) showed significant increase in latency to PTZ-induced seizures and ICES seizure threshold compared to control and intranasal ROS solution. Additionally, intranasal Ros-LCNPs provided effective protection against PTZ-induced status epilepticus. No impairment in cognitive functions was observed following intranasal Ros-LCNPs. The results suggested that Ros-LCNPs could be an effective and promising therapeutics for the epilepsy management.

Electrophysiological parameters that contribute to the pathogenesis of familial amyloid polyneuropathy caused by transthyretin mutations

Familial amyloid polyneuropathy (FAP) is a rare, hereditary peripheral neuropathy commonly caused by mutations in human transthyretin (TTR) gene. Clinically, FAP caused by TTR mutations (TTR-FAP) involves both large and small nerve fibers. Details of early electrophysiological features in TTR-FAP remain unclear. To address this issue, we evaluated nerve excitability (NET) results in motor axons of control mice and two transgenic mouse models carrying V30M (TTRV30M) or A97S (TTRA97S) mutations that simulate clinical features of TTR-FAP. Transgenic TTRV30M and TTRA97S mice demonstrated significant increases in latency in hindlimb withdraw tests, as well as, poor rotarod test performance, compared to TTRORF mice. NET evaluation showed reduced S2 accommodation, and increased TEdundershoot during threshold electrotonus (TE) in motor axons of both TTRV30M and TTRA97S mice, indicating that axonal membranes were in a depolarized state. Decreased rheobase combined with increased refractoriness in the transgenic mice suggested that there were reduced sodium currents. Further immunohistochemical study of the sciatic nerves revealed the significantly decrease of voltage-gated sodium channel expression in the transgenic mice. Moreover, superexcitability during the recovery cycle is significantly increased in transgenic mice compared with control mice, which is attributed to increased internodal capacitance. Finally, the electron microscopy demonstrated the reduced g-ratio in TTRA97S mice may correlate with an atrophic change of axons and/or increase of myelin thickness. In summary, we evaluated NET results in transgenic mice which modeled the clinical features presented in TTR-FAP patients. Reduced sodium channel expression and increased internodal capacitance are factors contributing to the electrophysiological changes in TTR-FAP.

Study on the effect of diallyl sulfide on peripheral nerve injury in n-hexane intoxicated rats

Objective: To investigate the antagonistic effect of diallyl sulfide (DAS) against peripheral nerve injury induced by n-hexane in rats. Methods: A total of 68 adult male Wistar rats were selected, among which 50 were randomly selected and divided into blank control group, DAS control group (100 mg/kg·bw) , n-hexane model group, low-dose DAS intervention group (50 mg/kg·bw) , and high-dose DAS intervention group (100 mg/kg·bw) . A rat model of peripheral nerve injury was established by n-hexane exposure, and the rats were treated with DAS at different doses. The changes in pyrrole adducts and behavior were observed, a metabolic analysis was performed for serum pyrrole adducts, and the intervention effect was evaluated. The remaining 18 rats were randomly assigned to the n-hexane model group, the low-dose DAS intervention group, and the high-dose DAS intervention group, with 6 rats in each group, as satellite groups used for the toxicokinetic analysis of serum pyrrole adducts. Results: Compared with the blank control group, the n-hexane model group and low-and high-dose DAS intervention groups had a significant reduction in body weight since week 2 (P<0.01) . Compared with the n-hexane model group at the end of the experiment at week 7, the high-dose DAS intervention group had a significantly higher body weight (P<0.05) , while there was no significant difference in body weight between the n-hexane model group and the low-dose DAS intervention group (P>0.05) . The n-hexane model group developed gait abnormality at week 2 of poisoning, while the low-and high-dose DAS intervention groups developed gait abnormality at weeks 3 and 5 of poisoning, respectively. At the end of the experiment, the n-hexane model group and the low-and high-dose DAS intervention groups had a significantly higher gait score than the blank control group (P<0.01) . At the end of the experiment, the n-hexane model group and the low-dose DAS intervention group had significantly shorter latency in rotarod test than the blank control group (P<0.01) , while there was no significant difference in latency between the DAS control group and the high-dose DAS intervention group (P>0.05) . Compared with the n-hexane model group, the low-and high-dose DAS intervention groups had a significant increase in latency in rotarod test (P<0.01) . Compared with blank control group, the n-hexane model group and the low-dose DAS intervention group had a significant increase in mean nerve conduction velocity (P<0.01) , while there was no significant difference between the blank control group and the DAS control group or high-dose DAS intervention group (P>0.05) , and compared with the n-hexane model group, the low-and high-dose DAS intervention groups had a significant increase in nerve conduction velocity (P<0.01) . Compared with the blank control group at the end of the experiment at week 7, the n-hexane model group and the low-and high-dose DAS intervention groups had significant increases in the concentration of pyrrole adducts in serum, urine, and hair (P<0.01) , while there was no significant difference between the blank control group and the DAS control group (P>0.05) , and the high-dose DAS intervention group had a significantly lower concentration of pyrrole adducts in serum, urine, and hair than the low-dose DAS intervention group (P<0.05) . Serum pyrrole adducts reached the peak level at 9-12 hours and then started to decrease. Compared with the n-hexane model group, the high-and low-dose DAS intervention groups had a significantly shorter half-life period of serum pyrrole adducts (P<0.01) . Compared with the n-hexane model group, the high-and low-dose DAS intervention groups had a significant reduction in the area under the curve of serum pyrrole adducts (P<0.05) . Conclusion: DAS can antagonize peripheral nerve injury induced by n-hexane.

Investigating the Effects of Subchronic Sesame and Flaxseed Oils Consumption Against Seizure and Depression in Adult Male Mice

Epilepsy is a highly debilitating disorder by unpredictable seizures associated with emotional disturbance. One potential treatment for seizure and depression is dietary therapy. So, this study evaluated effects of daily oral administration of sesame and flaxseed oils in depression and seizure. Twenty-one adult male mice were divided into the following groups: control (normal saline recipient, 1ml/kg (, sesame and flaxseed oils groups (8ml/kg bodyweight, for 21 days). At the 22nd day, locomotor activity and depressive - like behavior were assessed by open field and tail suspension tests. Also in 23rd day, animals received a subcutaneous injection of strychnine for induction of seizure. The seizure latency and death time were recorded through observation of animal behavior immediately after injection of strychnine. There were no significant differences in locomotor activity among control, sesame and flaxeed groups. But it has been shown a significant increase in latency to immobility (p=0.027) and decrease in total immobility (p=0.001) in flaxseed oil group compared to control group. Also sesame oil group showed a significant reduction in the duration of total immobility (p=0.027) and its latency to immobility wasn’t significant. There were no significant differences in latency to seizure and death time in flaxseed oil groups compared to the control group. The subchronic consumption of sesame oil significantly increased the death time than the control group (p=0.04) but the latency to seizure was not significant. The results reveal that sesame and flaxseed may be considered as a food adjuvant for attenuating emotional problems in epilepsy.

Antipyretic and anti-nociceptive effects of methanol extract of leaves of Fimbristylis miliacea in mice model

Ethnopharmacological relevanceFimbristylis miliacea (L.) Vahl (Cyperaceae) is a grass like herb usually grows as a weed in rice fields and is mainly distributed in tropical or sub-tropical countries of south and south-east Asia, central America, northern Australia and west Africa. The plant has been traditionally used to treat fever as a form of poultice. Aim of the studyThe present study aimed to investigate antipyretic and anti-nociceptive effects of methanol extract of leaves of Fimbristylis miliacea in mice model. Materials and methodsAntipyretic effect of Fimbristylis miliacea was examined using Baker's yeast induced hyperthermia test. Anti-nociceptive effect was investigated using acetic acid induced writhing test, formalin induced hind paw licking test and hot plate test. ResultsThe extract at concentration of 400 mg/kg produced significant reduction in body temperature after 0.5 h of administration (4.12 °F, p ≤ 0.001) and continued to decrease (after 4 h, 5.92 °F, p ≤ 0.001). Extracts at 100 mg/kg and 200 mg/kg decreased the temperature by about 2.77 °F (from 99.47 °F to 96.7 °F) and 5.58 °F (98.2 °F–92.62 °F) respectively after 4 h whereas paracetamol dropped by about 7.2 °F (p ≤ 0.001). The extract showed significant decrease in number of writhes at all concentrations. Highest effect was found at 200 mg/kg having 35.7 writhes (p ≤ 0.001), much lower than control (89.2); standard drug diclofenac showed 23.2 writhes. Percent inhibition of writhing were 54.26 and 73.99 for 200 mg/kg and diclofenac respectively. The result of hind paw licking test also corroborated writhing test. Significant reduction in percent inhibition of licking was observed mainly in late phase. Percent inhibition of licking were 93.77 and 51.55 for 400 mg/kg extract and diclofenac respectively. In hot plate test, extract at 400 mg/kg showed significant increase in latency from 10.77 s to 13.59 s (p ≤ 0.05). Extract at this dose after 2 h demonstrated greater percent maximal effect (43.26%) compared to ketorolac (40.19%). ConclusionThe experiment confirmed the traditional use of F. miliacea in the treatment of fever with possible anti-nociceptive effects.

A cross sectional study of effects of mobile phone exposure on Brainstem evoked response audiometry (BERA)

Human physiology creates a framework for understanding how the human body adapts to stresses, physical activity and disease. Best example is usage of mobile phones for daily routine. An attempt was made to study the effect of exposure to mobile phone on functions of ear. Hence, the objective of our study was to find out the effects of exposure of mobile phones on BERA in mobile phone users for long time. 18–30 years aged 100 normal healthy volunteers were considered for the study. Two groups of 50 each participant, who used mobile phones for 4 years for 60 minutes in each day and who used mobile phones since a year for 60 minutes per day respectively. Concise click acoustic stimuli alternating in polarity were presented by an earphone on the ear with 40 and 90 dB intensities. Recording of peak BERA latencies (I, III and V) and calculation of interpeak latency I - V were done. Analysis reveals significant prolongation of latencies in wave III and wave V in Group I participants and also significant prolongation of inter peak latency I - V in Group I participants. On comparison of various latencies of BERA in participants of both the groups, in Group I, a significant increase in latencies of the wave III and V was observed. This damage to the ear can be at various levels of auditory pathway and can be proportional to the amount and duration of exposure. Keywords: BERA, Interpeak latencies, Auditory pathway.

Pycnogenol Protects against Pentylenetetrazole-Induced Oxidative Stress and Seizures in Mice.

Epilepsy is one of the most common and severe brain disorders in the world, characterized by recurrent spontaneous seizures due to an imbalance between cerebral excitability and inhibition. Oxidative stress is a biochemical state in which reactive oxygen species are generated and associated with various diseases including epilepsy. Pycnogenol, a polyphenol obtained from the pine tree and has antioxidant & anti-inflammatory activity. So, the aim of the study was to evaluate the effect of Pycnogenol on pentylenetetrazole (PTZ)-induced seizures in mice. The mice of swiss strain each weighing 18-30g were used. Pycnogenol (50&100mg/kg) was suspended in carboxymethyl cellulose in saline and administered orally. Diazepam (1mg/kg, i.p) was used as a standard drug. The anticonvulsant effects of the drugs were measured using PTZ and cognitive behaviour was also assessed. The biochemical estimation was done by measuring Thiobarbituric acid, Superoxide dismutase, Catalase, and reduced glutathione followed by the histopathological study. Pycnogenol 50 & 100mg/kg showed a significant increase in latency to PTZ-induced seizures, decrease in duration and frequency of convulsions compared to control animals; however, the effects were dose-dependent and were more significant at a higher dose. No impairment in cognitive functions like memory and muscle relaxant was observed following pycnogenol 50 & 100 mg/kg. The effect of Pycnogenol on biochemical parameter was found to be significant. It significantly (p<0.01) decreases the level of TBARS and increases the levels of SOD, catalase, and GSH in the brain tissue. The histopathological evaluation showed less neuronal degeneration in the brain due to PTZ-induced seizures in comparison to control group. Thus pycnogenol has a protective approach towards convulsion and can be included as an adjuvant therapy with antiepileptic drugs.

Auditory Brainstem Response in Patients of Tinnitus with Sensorineural Hearing Loss.

Tinnitus is defined as phantom auditory perception without corresponding acoustic or mechanical correlates in cochlea. Existing evidence on its physiological basis is wide ranging, but its origin is still under exploration. To objectify this subjective phenomenon, Auditory Brainstem response test is used. The primary purpose of our study was to ascertain any significant difference in auditory electrophysiological response parameters in sensorineural hearing loss with tinnitus group when compared to controls (normal hearing subjects). Secondary aim was to find correlation of these parameters with degree of hearing loss and severity of tinnitus. This was a case control study conducted in the department of Otorhinolaryngology in tertiary care hospital, New Delhi over a period of one and half years. The study comprised of one hundred and sixty patients out of which, fifty-five patients were sensorineural hearing loss with tinnitus and fifty-one patients were normal hearing subjects. General medical and audiological assessment was done. Significant increase in latency of wave I, III, V and increase in inter peak latency of I-III, III-V, I-V was observed in tinnitus with sensorineural hearing loss group when compared to controls. It was reported that on increasing degree of hearing loss, there was increase in latency of wave I, III, V and increase in inter peak latency of wave I-III, I-V in the former group.

Delayed Visual Evoked Response is Linked to Vascular Endothelial Growth Factor and Autonomic Dysfunction in Type 2 Diabetes Mellitus

Aims: In this study, we aimed to assess the link between visual evoked potentials (VEP), angiogenic marker (VEGF) and autonomic function tests in type-2 diabetes mellitus (T2DM). Methods: Age-matched 86 male subjects (44 type-2 diabetics on treatment and 42 normal healthy volunteers) were recruited for this study. Body mass index (BMI), basal cardiovascular parameters, spectral analysis of heart rate variability (HRV), were assessed. Fasting blood glucose, insulin, HOMA-IR and VEGF were estimated. The independent association of the P100 latency of VEP with VEGF was determined by multiple regression analysis. Results: LF-HF ratio a marker of sympathovagal balance, increased significantly (p=0.0287) in diabetic group compared to the control group. Comparison of visual evoked potentials between controls and diabetic groups showed significant increase in latency of P100 of both the eyes (right eye p<0.0001, left eye p=0.0003) among the cases. There was significant increase (p=0.0091) in VEGF in diabetic subjects when compared to control. Also positive and significant correlation of P100 latency of VEP with VEGF is seen in diabetics. Conclusions: There is delayed latency of VEP and increased VEGF in type 2 diabetic people. The correlation between VEP and VEGF could indicate the probable role of angiogenesis leading to reduced integrity of the neural pathways in T2DM.

Behavioral Variant Frontotemporal Dementia Performance on a Range of Saccadic Tasks.

Saccadic paradigms display changes across a number of degenerative conditions reflecting changes in the oculomotor pathway which in some conditions have been linked to disease presentation. To examine a novel range of saccadic paradigms in behavioral variant frontotemporal dementia (bvFTD). Prosaccade, predictive, self-paced, memory-guided, and anti-saccade tasks were examined in bvFTD patients and controls. A significant increase in latency for the bvFTD group was seen in all tasks. Self-paced saccades are reduced in number, memory-guided saccades display an increase in errors. Predictive saccades show an increased latency that does not remain when prosaccade latency changes are accounted for. While changes were seen across a range of paradigms, no individual task completely separated bvFTD from control participants. bvFTD patients as a group display a number of changes on saccadic testing which may reflect the frontal lobe changes seen in this condition.

αCGRP Transgenic Mice Display Typical Physiologic Features

Calcitonin gene-related peptide (CGRP) plays an important role in several physiological processes such as vasodilation, cardiovascular homeostasis and transmission of pain. Here we report the generation of a transgenic mouse overexpressing αCGRP and the impact of this on baseline physiological responses. αCGRP transgenic mice displayed significantly increased αCGRP mRNA levels in the kidney, heart and hippocampus. To assess cardiovascular physiology, we measured arterial pressure using a tail cuff system. Heart rate, systolic pressure, mean arterial pressure and diastolic pressure were significantly lower in αCGRP transgenic mice than wild-type mice. To assess pain, a hot plate test was performed and the latency of response was used as an indicator of supraspinal response. In addition, a tail immersion test was performed to assess thermal nociception. A significant increase in latency was observed in the αCGRP transgenic mice when compared with wild-type mice in both tests. These results suggest that αCGRP overexpression causes an increase in thermal reaction and downregulation of the cardiovascular system, presumably due in increased levels of αCGRP.

Assessment of Acupuncture and Moxibustion Effects on the Electrophysiological Properties of the Ulnar Nerve: A Nerve Conduction Study

Background/Aims: Acupuncture and moxibustion, when used together, have act mechanically and thermally on treated reflexological areas. The main goal of this work was to evaluate the effects of acupuncture and moxibustion on the electrophysiological properties of the ulnar nerve. Methods: Electrical stimulation was applied to the ulnar nerve above the epi­condyle of 28 volunteers. A 20-V potential was applied, and after each 10 impulses it was increased by 10 V, up to a maximum of 80 V. At 20 and 80 V, the participants were asked to rate the discomfort from 0 to 10 on a Numeric Rating Scale for pain. After the first stimulation and data collection, the control group rested for 6 min, while the intervention group was submitted to acupuncture and moxibustion on Lingdao (HT 4). Following this period of time, a second electrical stimulation was performed on both groups. Results: The discomfort was greater in the intervention group during the second stimulation. The stimulus required to achieve the maximum amplitude decreased, but the changes were only statistically significant in the intervention group (p = 0.006). An increase in latency and a decrease in reaction velocity were noticed between the first and the second stimulation for both groups; however, only the control group presented statistically significant differences (p = 0.018 and p = 0.022, respectively). Conclusions: Acupuncture and moxibustion on HT 4 increased the electrical sensitivity, decreased the stimulus intensity to achieve the maximum amplitude, and avoided a significant increase in latency and decrease in reaction velocity in two consecutive electrical stimulations.

Usefulness of P300 audiological test assessment in patients with snoring for cognitive ability

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; Snoring is a sleep disorder which often causes cognitive dysfunction, due to inadequate rhythms of sleep cycle. Commonly evaluated with polysomnography. P300 is an electrophysiological method to measure the cognitive dysfunction. Usefulness of P300 audiological test in snoring for cognitive ability is studied here.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; Prospective study with 20 cases and 30 controls. Cases were selected with simple sleep apnoea questionnaires and snoring people were selected as cases. Healthy non snoring people were selected as controls. &lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; Significant increase in latency of P300 in snoring people (50%); more in males and in the middle aged group.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; P300 is an electrophysiological method to measure the cognitive dysfunction in snoring people.&lt;/p&gt;

Haloperidol-induced parkinsonism is attenuated by varenicline in mice.

Background Parkinson's disease (PD) is a neurodegenerative disorder of the central nervous system (CNS). However, there is no known drug to stop/slow down this neurodegeneration. Varenicline is an anti-smoking drug and has the potential to prevent neurodegeneration. Thus, the present study was designed to evaluate the effect of varenicline in animal models of PD. Methods Levodopa and haloperidol were administered in doses of 30 and 1 mg/kg, intraperitoneally (i.p.), respectively. Group 1 was administered haloperidol; groups 2, 3 and 4 were administered haloperidol along with varenicline in doses of 0.5, 1.5 and 2.5 mg/kg, i.p., respectively and group 5 was administered levodopa along with haloperidol. Varenicline was administered daily, 30 min prior to the administration of haloperidol. Varenicline was administered for the first 8 days, and then from the 9th day until the 15th day. Behavioral assessment (rotarod and catalepsy tests) was performed on days 9 and 15. Assessment of striatal dopamine levels and histopathology were also performed. Results In the haloperidol-treated groups, significant decrease in latency to fall off (on rotarod) and increase in catalepsy duration (in catalepsy test) were observed as compared to the control group. In the levodopa-treated group, significant increase in latency to fall off the rotarod and significant decrease in catalepsy duration were observed as compared to the haloperidol-treated groups. Further, on day 9, varenicline (2.5 mg/kg) significantly increased the latency to fall off the rotarod, while varenicline (0.5 and 1.5 mg/kg) did not cause any significant change in latency to fall off the rotarod as compared to the haloperidol-treated group. On day 15, significant increase in latency to fall off the rotarod was observed in varenicline (at all doses) as compared to the haloperidol-treated group. In the catalepsy test, the varenicline-treated (at all doses) groups showed significant decrease in duration of catalepsy on day 9 and day 15 as compared to the haloperidol-treated group. Significant decrease in striatal dopamine levels was observed among the haloperidol-treated groups as compared to the control group. Further, varenicline-treated (at all doses) and levodopa-treated groups showed significant increase in striatal dopamine levels when compared with the haloperidol-treated group. In histology, varenicline (0.5 mg/kg) showed moderate decrease in neurons, while varenicline (1.5 and 2.5 mg/kg) showed mild decrease in neurons. However, the levodopa-treated group did not show any significant decrease in neurons. Thus, varenicline has shown promising results and has provided novel strategy for the treatment of PD.

Increased latencies to respond in a judgment bias test are not associated with pessimistic biases in rats

Extinction of learning is a common, yet under-reported limitation of judgment bias testing methods Repeated exposure to the ambiguous probe of a judgment bias paradigm encourages the animal to cease display of the required behaviours. However, there remains a need to repeatedly test animals to achieve statistical power. A delicate balance therefore needs to be struck between over- and under-exposure of the animals to the test conditions. This study presents the data of rats, a common animal subject of judgment bias testing. Rats were exposed to the ambiguous probe of a common, active-choice judgment bias test for 11 consecutive days. There was a significant increase in the latency to respond to the ambiguous probe following day 8, with no significant increase experienced for either the positive or less-positive probes. Following day 8 there was a significant increase in both optimistic and pessimistic latencies in response to the ambiguous probe. Therefore, repeated exposure to the ambiguous probe caused an increased latency in response even though optimistic interpretations were recorded. This implies that the use of response latency alone as a measure in judgment bias testing can falsely identify pessimism. Researchers should modify experimental design to include both choice and latency measures.

Injury mechanisms and electromyographic changes after injury of the recurrent laryngeal nerve: Experiments in a porcine model.

Recurrent laryngeal nerve (RLN) injury during surgery may reveal differences in electromyographic (EMG) changes after sustained compression or traction. In 20 pigs with the NIM-FLEX EMG-endotracheal tube, EMG was recorded at baseline, during sustained RLN compression, or traction until 70% amplitude decrease and during 30 minutes of recovery. Seventy percent amplitude decrease from baseline was reached after 110 ± 98 seconds (compression group) and 2034 ± 2108 seconds (traction group). Traction induced a pronounced latency increase, peaking at 122 ± 8% in contrast to compression with 106 ± 5% (P < .001). The EMG amplitude recovery to ≥50% of baseline failed in 7 nerves after compression and 8 nerves after traction. Compression caused a fast decrease of EMG amplitude with minor effects on latency. In contrast, RLN traction showed early and significant latency increase preceding a delayed amplitude decrease. Recovery rate of the EMG signals were similar in both groups.

Intranasal pitavastatin attenuates seizures in different experimental models of epilepsy in mice

This study was carried out to evaluate the effect of intranasal pitavastatin (PVS) on pentylenetetrazole (PTZ)-induced seizures, increasing current electroshock (ICES) seizures, and status epilepticus in mice. Intranasal PVS, 0.5 and 1.0mg/kg, showed significant increase in latency to PTZ-induced seizures and ICES seizure threshold compared to control; however, the effects were dose-dependent and were more significant at higher dose. Further, intranasal PVS (1.0mg/kg) but not intravenous PVS (50.0mg/kg) showed effective protection against PTZ-induced status epilepticus. No impairment in cognitive functions was observed following intranasal PVS (1.0mg/kg), thus making it a prospective therapeutic approach for acute seizures and status epilepticus.