Allele-specific RNA interference rescues the long-QT syndrome phenotype in human-induced pluripotency stem cell cardiomyocytes

Aims

Long-QT syndromes (LQTS) are mostly autosomal-dominant congenital disorders associated with a 1:1000 mutation frequency, cardiac arrest, and sudden death. We sought to use cardiomyocytes derived from human-induced pluripotency stem cells (hiPSCs) as an in vitro model to develop and evaluate gene-based therapeutics for the treatment of LQTS.

Methods and results

We produced LQTS-type 2 (LQT2) hiPSC cardiomyocytes carrying a KCNH2 c.G1681A mutation in a I_Kr ion-channel pore, which caused impaired glycosylation and channel transport to cell surface. Allele-specific RNA interference (RNAi) directed towards the mutated KCNH2 mRNA caused knockdown, while leaving the wild-type mRNA unaffected. Electrophysiological analysis of patient-derived LQT2 hiPSC cardiomyocytes treated with mutation-specific siRNAs showed normalized action potential durations (APDs) and K⁺ currents with the concurrent rescue of spontaneous and drug-induced arrhythmias (presented as early-afterdepolarizations).

Conclusions

These findings provide in vitro evidence that allele-specific RNAi can rescue diseased phenotype in LQTS cardiomyocytes. This is a potentially novel route for the treatment of many autosomal-dominant-negative disorders, including those of the heart.

Cardiomyopathy due to nonsustained ventricular tachycardia originating from the aortic sinus cusp

We report a case of idiopathic nonsustained ventricular tachycardia (VT) originating from the aortic sinus cusp referred for presyncope and LV dysfunction and frequent premature ventricular complex with no response to 3 months anti-arrhythmic medication for heart failure and arrhythmia. She was then referred to us for frequent PVC's and runs of nonsustained VT. ECG recorded during the nonsustained VT showed a left bundle branch block pattern in the precordial leads and an inferior axis and early transition in precordial leads in V3-V4. QS morphology in lead V1 was noticed with notching on the downward deflection. Electrophysiologic study was conducted to map ventricular outflow tract as a classic method, although pace map failed to find any matched QRS with the spontaneous PVCs. The mapping of aortic cusps was also performed. The best potential was recorded in a region located at the commissure of left-right aortic cusps. A single radiofrequency energy was delivered which resulted in immediate elimination of PVCs. The patient was discharged the day after ablation without any PVC recorded on monitor. Left ventricular ejection fraction(LVEF) improved to normal level two months later. There was no PVC detected at serial holter monitoring. It seems logical not to overlook even an isolated or nonsustained ventricular arrhythmia considering the available and effective treatments such as ablation rather than congestive heart failure(CHF) therapy especially in a young patient.

Dual effects of L-DOPA on nigral dopaminergic neurons

L-DOPA (Levodopa) remains the gold standard for the treatment of motor symptoms of Parkinson's disease (PD), despite indications that the drug may have detrimental effects in cell culture. Classically, l-DOPA increases the production of dopamine (DA) in nigral dopaminergic neurons, while paradoxically inhibiting the firing of these neurons due to activation of D2 autoreceptors by extracellularly released DA. Using a combination of electrophysiology and calcium microfluorometry in brain slices, we have identified a novel effect of L-DOPA on dopaminergic neurons when D2 receptors were blocked. Under these conditions, L-DOPA (0.03-3 mM) evoked an excitatory effect consisting of two components. The 'early' component observed during and immediately after application of the drug, was associated with increased firing, membrane depolarization and inward current. This excitatory response was strongly attenuated by CNQX (10 μM), pointing to the involvement of TOPA quinone, an auto-oxidation product of L-DOPA and a potent activator of AMPA/kainate receptors. The 'late' phase of excitation persisted >30 min after brief L-DOPA application and was not mediated by ionotropic glutamate receptors, nor by D1, α1-adrenergic, mGluR1 or GABAB receptors. It was eliminated by carbidopa, demonstrating its dependence on conversion of L-DOPA to DA. Exogenous DA (50 μM) also evoked a glutamate-receptor independent increase in firing and an inward current when D2 receptors were blocked. In voltage-clamped neurons, both L-DOPA and DA produced a long-lasting increase in [Ca(2+)]i which was unaffected by block of ionotropic glutamate receptors. These results demonstrate that L-DOPA has dual, inhibitory and excitatory, effects on nigral dopaminergic neurons, and suggest that the excitation and calcium rise may have long-lasting consequences for the activity and survival of these neurons when the expression or function of D2 receptors is impaired.

Comparison of different methods of intestinal obstruction in a rat model

AIM: To investigate different methods of creating incomplete intestinal obstruction in a rat model and to compare their electrophysiologic, morphologic and histologic characteristics.

METHODS: Rat ileum was partially obstructed by the respective application of: braided silk (penetrated the mesentery and surrounded intestine); half ligation (penetrated directly and ligated 1/2 cross-section of the intestine); wide pipe (6 mm in width, surrounded the intestine); narrow pipe (2 mm in width, surrounded the intestine). A control was also included (no obstruction). Various behavioral and electrophysiologic variables, as well as morphologic and immunohistochemical observations were recorded by blinded investigators at different time points (12, 24, 48, 72 h), including daily general condition, ileal wet weight and circumference, macromorphous and micromorphous intestine, bowel movement capability in vivo and in vitro, slow wave and neural electrical activity, and the number of c-Kit positive interstitial cells of Cajal (ICC).

RESULTS: Despite being of a similar general condition, these methods resulted in different levels of obstruction in each group compared with the control at different time points (12, 24, 48, 72 h). However, these fields of the wide pipe rat showed significantly differences when compared with the other three obstructed groups at 12 to 72 h, including macroscopic and histological presentation, intestinal transit ratio and contractility, circumference and wet weight, amplitude and frequency of nerve electrical discharge and slow wave, and ICC numbers (all P < 0.01).

CONCLUSION: The wide pipe rat method is significantly more reliable and stable than the other methods of obstruction, demonstrating that use of the wide pipe method can be a useful model of incomplete intestinal obstruction.

Neurophysiological approach to disorders of peripheral nerve

Disorders of the peripheral nerve system (PNS) are heterogeneous and may involve motor fibers, sensory fibers, small myelinated and unmyelinated fibers and autonomic nerve fibers, with variable anatomical distribution (single nerves, several different nerves, symmetrical affection of all nerves, plexus, or root lesions). Furthermore pathological processes may result in either demyelination, axonal degeneration or both. In order to reach an exact diagnosis of any neuropathy electrophysiological studies are crucial to obtain information about these variables. Conventional electrophysiological methods including nerve conduction studies and electromyography used in the study of patients suspected of having a neuropathy and the significance of the findings are discussed in detail and more novel and experimental methods are mentioned. Diagnostic considerations are based on a flow chart classifying neuropathies into eight categories based on mode of onset, distribution, and electrophysiological findings, and the electrophysiological characteristics in each type of neuropathy are discussed.

Lessons from dissociated pulmonary vein potentials: entry block implies exit block

Aims

Prior reports using pacing manoeuvres, demonstrated an up to 42% prevalence of residual pulmonary vein to left atrium (PV–LA) exit conduction after apparent LA–PV entry block. We aimed to determine in a two-centre study the prevalence of residual PV–LA exit conduction in the presence of unambiguously proven entry block and without pacing manoeuvres.

Methods and results

Of 378 patients, 132 (35%) exhibited spontaneous pulmonary vein (PV) potentials following circumferential PV isolation guided by three-dimensional mapping and a circular mapping catheter. Pulmonary vein automaticity was regarded as unambiguous proof of LA–PV entry block. We determined the prevalence of spontaneous exit conduction of the spontaneous PV potentials toward the LA. Pulmonary vein automaticity was observed in 171 PVs: 61 right superior PV, 33 right inferior PV, 47 left superior PV, and 30 left inferior PV. Cycle length of the PV automaticity was >1000 ms in all cases. Spontaneous PV–LA exit conduction was observed in one of 171 PVs (0.6%). In a subset of 69 PVs, pacing from within the PV invariably confirmed PVLA exit block.

Conclusion

Unidirectional block at the LA–PV junction is unusual (0.6%). This observation is supportive of LA–PV entry block as a sufficient electrophysiological endpoint for PV isolation.

Effects of human mesenchymal stem cell transplantation combined with polymer on functional recovery following spinal cord hemisection in rats

The spontaneous axon regeneration of damaged neurons is limited after spinal cord injury (SCI). Recently, mesenchymal stem cell (MSC) transplantation was proposed as a potential approach for enhancing nerve regeneration that avoids the ethical issues associated with embryonic stem cell transplantation. As SCI is a complex pathological entity, the treatment of SCI requires a multipronged approach. The purpose of the present study was to investigate the functional recovery and therapeutic potential of human MSCs (hMSCs) and polymer in a spinal cord hemisection injury model. Rats were subjected to hemisection injuries and then divided into three groups. Two groups of rats underwent partial thoracic hemisection injury followed by implantation of either polymer only or polymer with hMSCs. Another hemisection-only group was used as a control. Behavioral, electrophysiological and immunohistochemical studies were performed on all rats. The functional recovery was significantly improved in the polymer with hMSC-transplanted group as compared with control at five weeks after transplantation. The results of electrophysiologic study demonstrated that the latency of somatosensory-evoked potentials (SSEPs) in the polymer with hMSC-transplanted group was significantly shorter than in the hemisection-only control group. In the results of immunohistochemical study, β-gal-positive cells were observed in the injured and adjacent sites after hMSC transplantation. Surviving hMSCs differentiated into various cell types such as neurons, astrocytes and oligodendrocytes. These data suggest that hMSC transplantation with polymer may play an important role in functional recovery and axonal regeneration after SCI, and may be a potential therapeutic strategy for SCI.

Over-expression of N-type calcium channels in cortical neurons from a mouse model of Amyotrophic Lateral Sclerosis

Voltage-gated Ca(2+) channels (VGCCs) mediate calcium entry into neuronal cells in response to membrane depolarisation and play an essential role in a variety of physiological processes. In Amyotrophic Lateral Sclerosis (ALS), a fatal neurodegenerative disease caused by motor neuron degeneration in the brain and spinal cord, intracellular calcium dysregulation has been shown, while no studies have been carried out on VGCCs. Here we show that the subtype N-type Ca(2+) channels are over expressed in G93A cultured cortical neurons and in motor cortex of G93A mice compared to Controls. In fact, by western blotting, immunocytochemical and electrophysiological experiments, we observe higher membrane expression of N-type Ca(2+) channels in G93A neurons compared to Controls. G93A cortical neurons filled with calcium-sensitive dye Fura-2, show a net calcium entry during membrane depolarization that is significantly higher compared to Control. Analysis of neuronal vitality following the exposure of neurons to a high K(+) concentration (25 mM, 5h), shows a significant reduction of G93A cellular survival compared to Controls. N-type channels are involved in the G93A higher mortality because ω-conotoxin GVIA (1 μM), which selectively blocks these channels, is able to abolish the higher G93A mortality when added to the external medium. These data provide robust evidence for an excess of N-type Ca(2+) expression in G93A cortical neurons which induces a higher mortality following membrane depolarization. These results may be central to the understanding of pathogenic pathways in ALS and provide novel molecular targets for the design of rational therapies for the ALS disorder.

Dynamic causal modelling of lateral interactions in the visual cortex

This paper presents a dynamic causal model based upon neural field models of the Amari type. We consider the application of these models to non-invasive data, with a special focus on the mapping from source activity on the cortical surface to a single channel. We introduce a neural field model based upon the canonical microcircuit (CMC), in which neuronal populations are assigned to different cortical layers. We show that DCM can disambiguate between alternative (neural mass and field) models of cortical activity. However, unlike neural mass models, DCM with neural fields can address questions about neuronal microcircuitry and lateral interactions. This is because they are equipped with interlaminar connections and horizontal intra-laminar connections that are patchy in nature. These horizontal or lateral connections can be regarded as connecting macrocolumns with similar feature selectivity. Crucially, the spatial parameters governing horizontal connectivity determine the separation (width) of cortical macrocolumns. Thus we can estimate the width of macro columns, using non-invasive electromagnetic signals. We illustrate this estimation using dynamic causal models of steady-state or ongoing spectral activity measured using magnetoencephalography (MEG) in human visual cortex. Specifically, we revisit the hypothesis that the size of a macrocolumn is a key determinant of neuronal dynamics, particularly the peak gamma frequency. We are able to show a correlation, over subjects, between columnar size and peak gamma frequency — that fits comfortably with established correlations between peak gamma frequency and the size of visual cortex defined retinotopically. We also considered cortical excitability and assessed its relative influence on observed gamma activity. This example highlights the potential utility of dynamic causal modelling and neural fields in providing quantitative characterisations of spatially extended dynamics on the cortical surface — that are parameterised in terms of horizontal connections, implicit in the cortical micro-architecture and its synaptic parameters.

Spinal accessory neuropathy in patients with chronic neck pain

AIM: To assess the presence of spinal accessory neuropathy in patients with chronic neck pain.

METHODS: Patients with pain either regional or focal in the neck or shoulders for at least 6 mo (chronic neck pain) were recruited randomly from the Rheumatology and Rehabilitation Outpatient Clinic at the Faculty of Medicine-Suez Canal University. Two groups were compared: 30 patients with chronic neck pain with mean age (36.97 ± 12.45 years) and 10 apparently healthy controls. Trapezius muscle examination including inspection and range of motion both active and passive was performed. A full clinical neurological examination was carried out to exclude peripheral neuropathy and motor neuron disease. According to the subject’s type of work, cases were categorized into labor-intensive and non-labor intensive tasks. A nerve conduction study (NCS) was performed on spinal accessory nerves at both sides for all patients and controls. Parameters including latencies and amplitudes of compound motor action potential (CMAP) were compared with the chronicity of neck pain using the neck disability score. This cross sectional study was carried in the Rheumatology and Rehabilitation Department, at Suez Canal University Hospital, Ismailia, Egypt.

RESULTS: Physical examination revealed that 80% of cases had spinal trapezius muscle spasm. Restricted neck motion was present in 16.6% of cases. No one suffered from muscle wasting or weakness. Pain was bilateral in 18 patients (60%), localized to the right side in six patients (20%) and localized to the left side in six patients (20%). The causes of neck pain in the patients studied were nonspecific, due to physical stresses, cervical spondylosis and mild cervical disc herniation. Mean disease duration in patients with labor-intensive tasks was (3.9 ± 2.1 years), which was longer than that in patients with non-labor intensive tasks (3.1 ± 1.9 years); however, this difference was statistically insignificant. Spinal accessory NCSs were performed while subjects were in sitting positions and relaxed with naturally suspended arms to minimize muscular movement. The results of electrophysiological studies revealed that mean right and left latencies of the spinal accessory nerve were 2.96 ± 0.69 ms, 2.98 ± 0.61 ms in the patient group and 2.44 ± 0.38 ms, 2.33 ± 0.36 ms in control group respectively. These differences were statistically significant with P = 0.028 and 0.006 respectively. Spinal accessory NCS showed normal CMAP amplitude in both patients and controls. Comparing the results of the neck disability index (NDI) to different characteristics in patients with chronic neck pain, showed that patients with labor-intensive work had a higher NDI score mean (34.7 ± 9.5) compared to those with non-labor-intensive work, with significant statistical difference (P = 0.011). In addition, mean NDI scores were higher in males, and patients aged over 40 years and this difference was statistically significant (P = 0.007 and P = 0.009 respectively). Correlation studies between right and left spinal accessory nerve latencies and disability percent calculated using the NDI revealed a positive correlation. Moreover, there was a positive correlation between age and disability percent.

CONCLUSION: This study demonstrates electrophysiological evidence of demyelination in a significant proportion of patients with chronic cervical pain.

Interventional electrophysiology in children: a single-center experience

OBJECTIVE

Ablation techniques of cardiac arrhythmia in children have significantly progressed in the past decade; however, the number of pediatric ablations is still significantly lower than that in adults. Accordingly, there is less information regarding the success rate and complications in this age group.

METHODS

All pediatric ablations conducted between March 2005 and February 2011 at Rajaie Heart Center were studied. Abolishing the arrhythmia source by the end of procedure was considered as success. Recurrences before hospital discharge and those thereafter were named early recurrence and late recurrence, respectively.

FINDINGS

A total of 125 catheter ablations were performed for 112 patients. Of them 118 (94.4%) procedures were successful. The success rate was significantly higher in the patients with atrioventricular nodal reentry tachycardia (AVNRT). Of 105 patients who continued follow-up program, 7 (6.7%) cases experienced recurrence; the recurrence rate was inversely dependent on the patients' body size (P-value <0.05). There was no mortality. Five cases were complicated during or early after the procedure, all the complications were cured completely.

CONCLUSION

Therapeutic electrophysiology in children is an effective and relatively low-risk method. The recurrence and complication rates are similar to those reported in adults. Considering our results and the previous reports, pediatric patients with serious arrhythmia should not be deprived from ablation and should not be exposed to long-term toxic drugs.

Wolff-Parkinson-White syndrome in young people, from childhood to young adulthood: relationships between age and clinical and electrophysiological findings

Purpose

The aim of the present study was to evaluate the characteristics of electrophysiologic studies (EPS) and radiofrequency ablation (RFA) performed in subjects aged less than 30 years with Wolff-Parkinson-White (WPW) syndrome, particularly pediatric patients under 18 years of age, based on our experience.

Methods

Two hundred and one consecutive patients with WPW syndrome were recruited and divided to 3 groups according to age: group 1, 6 to 17 years; group 2, 18 to 29 years; and group 3, 30 to 60 years. The clinical, electrophysiological, and therapeutic data for these patients were evaluated by a retrospective medical record review.

Results

A total of 73 (36%) of these patients were <30 years of age. Although there were more males than females in group 2 (male:female, 31:11), there was no sex difference in group 1 (male:female, 16:15). Left accessory pathway was detected less frequently in group 1 (32%, 10/31) than in group 2 (57%, 24/42) and group 3 (63%, 81/128) (P=0.023 and P=0.002, respectively).

Conclusion

The present study describes several different electrophysiological characteristics in children and adolescents with WPW syndrome. Therefore, when EPS and RFA are performed in children and adolescence with WPW syndrome, we recommend that these characteristics be considered.

A case of atrial tachycardia originating from pulmonary vein invaded by lung cancer

A 59-year-old man during chemotherapy for squamous cell carcinoma of the lung, underwent catheter ablation of drug-refractory atrial tachycardia. Pulmonary venography and chest computed tomography revealed presence of stenotic, carcinomatous lesion of the left superior pulmonary vein. Excellent pace map and elimination of inducibility of atrial tachyarrhythmias after left pulmonary isolation suggested that the atrial tachycardia originated from the metastatic region.

Clinical, Electrophysiological Findings in Adult Patients with Non-traumatic Plexopathies

Objective

To ascertain the etiology of non-traumatic plexopathy and clarify the clinical, electrophysiological characteristics according to its etiology.

Method

We performed a retrospective analysis of 63 non-traumatic plexopathy patients that had been diagnosed by nerve conduction studies (NCS) and needle electromyography (EMG). Clinical, electrophysiological, imaging findings were obtained from medical records.

Results

We identified 36 cases with brachial plexopathy (BP) and 27 cases with lumbosacral plexopathy (LSP). The causes of plexopathy were neoplastic (36.1%), thoracic outlet syndrome (TOS) (25.0%), radiation induced (16.7%), neuralgic amyotrophy (8.3%), perioperative (5.6%), unknown (8.3%) in BP, while neoplastic (59.3%), radiation induced (22.2%), neuralgic amyotrophy (7.4%), psoas muscle abscess (3.7%), and unknown (7.4%) in LSP. In neoplastic plexopathy, pain presented as the first symptom in most patients (82.8%), with the lower trunk of the brachial plexus predominantly involved. In radiation induced plexopathy (RIP), pain was a common initial symptom, but the proportion was smaller (50%), and predominant involvements of bilateral lumbosacral plexus and whole trunk of brachial or lumbosacral plexus were characteristic. Myokymic discharges were noted in 41.7% patients with RIP. Abnormal NCS finding in the medial antebrachial cutaneous nerve was the most sensitive to diagnose TOS. Neuralgic amyotrophy of the brachial plexus showed upper trunk involvement in all cases.

Conclusion

By integrating anatomic, pathophysiologic knowledge with detailed clinical assessment and the results of ancillary studies, physicians can make an accurate diagnosis and prognosis.

A frameless stereotaxic MRI technique for macaque neuroscience studies

MRI has achieved widespread use for preplanning neuroscience procedures for non-human primate studies. However, orienting imaging studies in stereotaxic space has relied primarily on using a stereotaxic frame or co-registering fiducial markers with the neuroimaging. In this study, we present a simple approach in which the MRI dataset is aligned to the bony landmarks that define the Frankfurt stereotaxic baseline plane, without the need for a stereotaxic frame or additional external fiducials. To facilitate localizing the bony landmarks (infraorbital margin, external bony auditory meatus) on the MRI scans additional imaging landmarks (mid ocular plane, temporomandibular joint) are discussed that provide supplementary and readily visible points of reference.

The frameless MRI stereotaxic technique was evaluated in 8 rhesus macaque monkeys using 3D fast gradient echo MRI images with 0.7mm isotropic resolution. 1) Difference in stereotaxic coordinates of fiducial markers was compared between a traditional stereotaxic frame and the frameless MRI technique (n=2). 2) Differences in stereotaxic coordinates for cerebral regions were compared between the frameless MRI technique and MRI obtained with the animal positioned in a MRI-compatible stereotaxic frame (n=4). 3) The frameless MRI technique was further refined to prescribe electrode penetrations within a dural recording chamber in stereotaxic coordinates relative to the electrode microdrive. Differences in MRI coordinates were compared with the electrode microdrive (n=3).

Mean localization of fiducial markers differed by 1.6 +/- 0.6 mm between the frameless MRI technique and a traditional stereotaxic frame. Between the frameless technique and an MRI-compatible stereotaxic frame, localization of cerebral anatomy differed by 2.8 +/- 2.2 mm with the primary source of error being a pitch-up rotation in the sagittal plane. This localization difference was reduced to 0.5 +/- 0.6 mm when this rotation was removed. Frameless MRI coordinates for electrode tracts within the dural recording chamber were within 0.5mm +/- 0.2 mm of the electrode microdrive readings.

This simple technique provides the ability to accurately plan surgery and neurophysiological recordings in an individual animal, and to define the location of cerebral anatomy and electrode or injection tracts using publically available software, and without the need for dedicated MRI-compatible localization hardware. The reduced need for deep anesthesia (a necessity with traditional stereotaxic frames) makes the technique more amenable for functional MRI studies. Since each animal provides the bony landmarks to define their own stereotaxic space, this technique is readily applicable to other species.

Synaptic consolidation: an approach to long-term learning

Synaptic plasticity is thought to be the basis of learning and memory, but it is mostly studied on the timescale of mere minutes. This review discusses synaptic consolidation, a process that enables synapses to retain their strength for a much longer time (days to years), instead of returning to their original value. The process involves specific plasticity-related proteins, and depends on the dopamine D1/D5 receptors. Here, we review the research on synaptic consolidation, describing electrophysiology experiments, recent modeling work, as well as behavioral correlates.

Aging-induced Seizure-related Changes to the Hippocampal Mossy Fiber Pathway in Forebrain Specific BDNF Overexpressing Mice

Aging confers an increased risk for developing seizure activity, especially within brain regions that mediate learning and synaptic plasticity. Brain derived neurotrophic factor (BDNF) is a member of the neurotrophin family that has an important role in regulating growth and development of the nervous system. BDNF is upregulated after pharmacological seizure induction and this upregulation contributes to enhanced excitability of the hippocampal mossy fiber-CA3 pathway, which is accompanied by neuropeptide Y (NPY) upregulation. Mice overexpressing a BDNF transgene in forebrain neurons provide an avenue for understanding the role of neurotrophic support in the aged hippocampus. In this study BDNF transgenic (TG) mice were utilized to determine whether increased BDNF expression through genetic manipulation resulted in age-related changes in hippocampal excitability and NPY expression. Spontaneous behavioral seizures were observed in TG mice, but not WT mice, past 5 months of age and the severity of behavioral seizures increased with age. Electrophysiological investigation of hippocampal CA3 activity indicated that slices from aged TG mice (86%), but not age-matched WT mice, or young TG mice, showed epileptiform activity in response to either repeated paired pulse or high frequency (tetanic) stimulation. Electrophysiological results were supported by the observation of robust ectopic NPY immunoreactivity in hippocampal mossy fibers of most aged TG mice (57%), which was absent in age-matched WT mice and young TG mice. The results from this study indicate that forebrain restricted BDNF overexpression produces age-related changes in hyperexcitability and NPY immunoreactivity in mossy fiber-CA3 pathway. Together, these data suggest that the capability for BDNF to promote epileptogenesis is maintained, and may be enhanced, in the aging hippocampus.

Electrophysiological evidences of organization of cortical motor information in the Basal Ganglia

During the last two decades, the many developments in the treatment of movement disorders such as Parkinson disease and dystonia have enhanced our understanding on organization of the basal ganglia, and this knowledge has led to other advances in the field. According to many electrophysiological and anatomical findings, it is considered that motor information from different cortical areas is processed through several cortico-basal ganglia loops principally in a parallel fashion and somatotopy from each cortical area is also well preserved in each loop. Moreover, recent studies suggest that not only the parallel processing but also some convergence of information occur through the basal ganglia. Information from cortical areas whose functions are close to each other tends to converge in the basal ganglia. The cortico-basal ganglia loops should be comprehended more as a network rather than as separated subdivisions. However, the functions of this convergence still remain unknown. It is important even for clinical doctors to be well informed about this kind of current knowledge because some symptoms of movement disorders may be explained by disorganization of the information network in the basal ganglia.

The influence of contrasts on directional and spatial frequency tuning in visual cortex areas 17/18 of the cat

Purpose

The purpose of this study was to investigate the effects of contrast display exposure on neuronal directional and spatial frequency tuning. Neuronal responses were recorded from ninety-four neurons in cortical areas 17 and 18 in two adult cats.

Methods

A multi-channel microelectrode was implanted in cortical areas 17 and 18 of two paralyzed and anaesthetized cats. Various drifting sinusoidal grating contrast displays were presented to one of the cats' eyes in the visual field. Contour plots based on the neuronal responses to the drifting sinusoidal grating displays using various contrasts (i.e., 0.4, 0.7, and 1.0) and velocities (i.e., 4.6, 13.9, 23.1, 32.3, 41.5, 50.8, and 60.0 deg/sec) were plotted as a function of the spatial frequency and the direction associated with each velocity and contrast used.

Results

Five parameters were extracted from these contour plots: 1) optimum response, 2) preferred direction, 3) optimum spatial frequency, 4) directional tuning width, and 5) spatial frequency bandwidth. To determine the optimal velocity, each parameter was plotted against each of the specific display contrasts used, and a 'best fit' line was established. Response amplitudes were dependent on the type of contrast utilized; however, the spatial frequency and directional tuning properties were stable for the cortical neurons assessed.

Conclusions

The results of the presentation of different contrasts on neuronal directional and spatial frequency tuning are consistent with behavioral results when medium and high contrast displays are used.

Pulmonary Vein Sleeves as a Pharmacologic Model for the Study of Atrial Fibrillation

OBJECTIVES

To review the electrophysiologic effects of antiarrhythmic agents in pulmonary veins (PV) sleeve preparations.

BACKGROUND

Ectopic activity arising from the PV plays a prominent role in the development of atrial fibrillation.

METHODS

Transmembrane action potentials were recorded from canine superfused left superior or inferior PV sleeves using standard microelectrode techniques. Acetylcholine (ACh, 1 μM), isoproterenol (1 μM), high calcium ([Ca2+]o=5.4mM) or a combination was used to induce early or delayed afterdepolarizations (EADs or DADs) and triggered activity.

RESULTS

In canine PV sleeves, ranolazine (10 μM) induced a marked use-dependent decrease in Vmax, a rate-dependent abbreviation of action potential duration (APD), but a rate-dependent increase in effective refractory period due to the development of post-repolarization refractoriness and eliminates rate-dependent delayed and late phase 3 early afterdepolarizations (DADs and EADs)-induced triggered activity induced by high calcium, isoproterenol, acetylcholine of their combination together with rapid pacing. Chronic amiodarone induced a prolongation of APD, a marked decrease in Vmax, and prevented the development of DADs and late phase 3 EADs-induced triggered activity. Combination of ranolazine and chronic amiodarone act synergistically to cause potent use-dependent depression of sodium channel-dependent parameters in PV sleeves but not ventricular tissues.

CONCLUSIONS

The PV sleeve preparation is a useful model for the study of pharmacologic agents for the treatment of atrial fibrillation. The effectiveness of these agents in arrhythmias induced in PV sleeves may indicate an antiarrhythmic action in eliminating the triggers responsible for AF.

Influence of Electromechanical Activity on Cardiac Differentiation of Mouse Embryonic Stem Cells

During differentiation, mouse embryonic stem cell-derived cardiomyocytes (mESC-CMs) receive electromechanical cues from spontaneous beating. Therefore, promoting electromechanical activity via electrical pacing or suppressing it by drug treatment might affect the cellular functional development. Electrical pacing was applied to confluent monolayers of mESC-CMs during late-stage differentiation (days 16-18). Alternatively, spontaneous contraction was suppressed by (a) blocking ion currents with CsCl (HCN channel), trazodone (T-type Ca2+ channel), or both CsCl and trazodone on days 11-18; or (b) applying blebbistatin (excitation-contraction uncoupler) on days 11-14. Electrophysiological properties and gene expression were examined on day 19 and 18, respectively. Optical mapping revealed no significant difference in conduction velocity (CV)in paced vs. non-pacedmonolayers, nor were there significant changes in gene expression of connexin-43, Na-Ca exchanger (NCX), or myosin heavy chain (MHC). However, CV variability among differentiation batches and CV heterogeneity within individual monolayers were significantly lower in paced mESC-CMs. Alternatively, while the four drug treatments suppressed contraction with varying degrees (up to complete inhibition), there was no significant difference in CV for any of the treatments compared with controls. Trazodone treatment significantly reduced CV variability as compared to controls, whereas CsCl treatment significantly reduced CV heterogeneity. Distinct changes in gene expression of connexin-43, MHC, HCNl, Cav3.1/3.2 were not observed. Electrical pacing, but not suppression of spontaneous contraction, during late-stage differentiation reduces the intrinsic variability of CV among differentiation batches and across individual monolayers, which can be beneficial in the application of ESCs for myocardial tissue repair.

Septal accessory pathway: anatomy, causes for difficulty, and an approach to ablation

Accessory pathway (AP) ablation is one of the most satisfying invasive electrophysiology procedures associated with high success rates and relatively few complications. Nevertheless, when APs are found on the cardiac septum, ablative procedures become complex, and unique pitfalls need to be avoided.These difficulties with septal ablation are magnified in the pediatric population. The relatively small heart, rapid nodal conduction, and proximity of the arterial system specifically complicate septal ablation in children. The electrophysiologist must use every tool in his or her armamentarium, including exact delineation of pathway location, identification of pathway potentials, detection of the presence of pathway slant, etc. In addition, an exact knowledge of the complex anatomy of the cardiac septum, including the posteroseptal space, the aortic cusp region, and the proximity of the AV conduction system and coronary vessels, becomes mandatory.In this review, we describe the developmental anatomy and regional anatomy of septal accessory pathways. We then discuss approaches to map specific to pathways in particularly problematic regions at or near the septum, including venous and aortic cusp related accessory pathways.

Radial neuropathy due to occupational lead exposure: Phenotypic and electrophysiological characteristics of five patients

Lead is a ubiquitous and versatile metal that has been used by mankind for many years. It is a toxic heavy metal that ranks as one of the most important environmental poisons in the world. Research conducted in recent years has increased public health concern about the toxicity of lead at low doses and has supported a reappraisal of the levels of lead exposure that may be safely tolerated in the workplace. Neuropathy is one complication of lead poisoning. The aim of this study is to describe the phenotypic and electrophysiological profile in five male patients working in a battery factory who developed radial nerve neuropathy due to lead exposure. All patients had elevated blood lead levels that were in the toxic range. The concerned regulatory bodies should make it mandatory for workers to undergo regular health checkups to detect signs of lead poisoning and must ensure that workers are aware about the ill effects of exposure to this metal. Chelation therapy removes lead from the blood and soft tissues and chronic lead exposure often requires repeated courses of treatment.

Parabrachial nucleus neuronal responses to off-vertical axis rotation in macaques

The caudal aspect of the parabrachial nucleus (PBN) contains neurons responsive to whole body, periodic rotational stimulation in alert monkeys (Balaban et al. in J Neurophysiol 88:3175-3193, 2002). This study characterizes the angular and linear motion-sensitive response properties of PBN unit responses during off-vertical axis rotation (OVAR) and position trapezoid stimulation. The OVAR responses displayed a constant firing component which varied from the firing rate at rest. Nearly two-thirds of the units also modulated their discharges with respect to head orientation (re: gravity) during constant velocity OVAR stimulation. The modulated response magnitudes were equal during ipsilateral and contralateral OVARs, indicative of a one-dimensional accelerometer. These response orientations during OVAR divided the units into three spatially tuned populations, with peak modulation responses centered in the ipsilateral ear down, contralateral anterior semicircular canal down, and occiput down orientations. Because the orientation of the OVAR modulation response was opposite in polarity to the orientation of the static tilt component of responses to position trapezoids for the majority of units, the linear acceleration responses were divided into colinear dynamic linear and static tilt components. The orientations of these unit responses formed two distinct population response axes: (1) units with an interaural linear response axis and (2) units with an ipsilateral anterior semicircular canal-contralateral posterior semicircular canal plane linear response axis. The angular rotation sensitivity of these units is in a head-vertical plane that either contains the linear acceleration response axis or is perpendicular to the linear acceleration axis. Hence, these units behave like head-based ('strapdown') inertial guidance sensors. Because the PBN contributes to sensory and interoceptive processing, it is suggested that vestibulo-recipient caudal PBN units may detect potentially dangerous anomalies in control of postural stability during locomotion. In particular, these signals may contribute to the range of affective and emotional responses that include panic associated with falling, malaise associated with motion sickness and mal-de-debarquement, and comorbid balance and anxiety disorders.

Identification of TRPM7 channels in human intestinal interstitial cells of Cajal

AIM: To investigate the characteristics of slow electrical waves and the presence of transient receptor potential melastatin-type 7 (TRPM7) in the human gastrointestinal (GI) tract.

METHODS: Conventional microelectrode techniques were used to record intracellular electrical responses from human GI smooth muscle tissue. Immunohistochemistry was used to identify TRPM7 channels in interstitial cells of Cajal (ICCs).

RESULTS: The human GI tract generated slow electrical waves and had ICCs which functioned as pacemaker cells. Flufenamic acid, a nonselective cation channel blocker, and 2-APB (2-aminoethoxydiphenyl borate) and La³⁺, TRPM7 channel blockers, inhibited the slow waves. Also, TRPM7 channels were expressed in ICCs in human tissue.

CONCLUSION: These results suggest that the human GI tract generates slow waves and that TRPM7 channels expressed in the ICCs may be involved in the generation of the slow waves.

Fever accentuates transmural dispersion of repolarization and facilitates development of early afterdepolarizations and torsade de pointes under long-QT Conditions

BACKGROUND

The arrhythmogenic effects of hyperthermia have been highlighted in the Brugada syndrome but remain largely unexplored in other arrhythmic syndromes. The present study examines the effect of hyperthermia on transmural dispersion of action potential duration (TD-APD), early afterdepolarization (EAD) activity, and torsade de pointes (TdP) under long-QT conditions.

METHODS AND RESULTS

Standard and floating glass microelectrodes were used to record action potentials from epicardial, M cell, and endocardial regions of the arterially perfused left ventricle wedge, from tissue slices isolated from these regions, and from isolated Purkinje fibers. A transmural ECG was simultaneously recorded across the wedge. Under baseline conditions and in the presence of I(Ks) block (chromanol 293B), hyperthermia (39 degrees C to 40 degrees C) abbreviated APD in tissue slices from all 3 regions. In the presence of I(Kr) block (E-4031), hyperthermia prolonged APD and induced or augmented EADs in M cell and Purkinje preparations at pacing cycle lengths > or = 800 ms but abbreviated APD in epicardium and endocardium, resulting in a marked accentuation of TD-APD. Ryanodine prevented the hyperthermia- induced EAD. In perfused wedge preparations, hyperthermia abbreviated APD throughout both in the absence or presence of I(Kr) or I(Ks) block and did not induce EADs or TdP. Combined I(Kr) and I(Ks) block increased TD-APD and induced EADs (4/12) and spontaneous TdP (3/12) at 36 degrees C to 37 degrees C; hyperthermia (39 degrees C to 40 degrees C) further accentuated TD-APD and facilitated the development of EAD activity (9/12) and TdP (6/12).

CONCLUSIONS

Our findings suggest that hyperthermia can be associated with an increased arrhythmic risk when the repolarization reserve of the myocardium is compromised.

Functional effects of KCNE3 mutation and its role in the development of Brugada syndrome

INTRODUCTION

The Brugada Syndrome (BrS), an inherited syndrome associated with a high incidence of sudden cardiac arrest, has been linked to mutations in four different genes leading to a loss of function in sodium and calcium channel activity. Although the transient outward current (I(to)) is thought to play a prominent role in the expression of the syndrome, mutations in I(to)-related genes have not been identified as yet.

METHODS AND RESULTS

One hundred and five probands with BrS were screened for ion channel gene mutations using single strand conformation polymorphism (SSCP) electrophoresis and direct sequencing. A missense mutation (R99H) in KCNE3 (MiRP2) was detected in one proband. The R99H mutation was found 4/4 phenotype positive and 0/3 phenotype-negative family members. Chinese hamster ovary (CHO)-K1 cells were co-transfected using wild-type (WT) or mutant KCNE3 and either WT KCND3 or KCNQ1. Whole-cell patch clamp studies were performed after 48 hours. Interactions between Kv4.3 and KCNE3 were analyzed in co-immunoprecipitation experiments in human atrial samples. Co-transfection of R99H-KCNE3 with KCNQ1 produced no alteration in current magnitude or kinetics. However, co-transfection of R99H KCNE3 with KCND3 resulted in a significant increase in the I(to) intensity compared to WT KCNE3+KCND3. Using tissues isolated from left atrial appendages of human hearts, we also demonstrate that K(v)4.3 and KCNE3 can be co-immunoprecipitated.

CONCLUSIONS

These results provide definitive evidence for a functional role of KCNE3 in the modulation of I(to) in the human heart and suggest that mutations in KCNE3 can underlie the development of BrS.

The effects of renovascular hypertension on repolarization of ventricular epicardium

BACKGROUND AND OBJECTIVE

Alterations in the recovery sequence of hypertrophied myocardium favour the development of cardiac arrhythmias. The aim of the present study was to investigate apex-to-base and interventricular heterogeneities in the duration of epicardial ventricular repolarization in rats with renovascular hypertension.

METHOD

Renovascular hypertension was induced in six Wistar rats by constricting the left renal artery for one month. Six sham-operated Wistar rats served as normotensive controls. Epicardial mapping was performed using 32 unipolar leads distributed over the apex and base of the heart ventricles under sinus rhythm. Activation-recovery intervals (ARIs) were calculated from electrograms.

RESULTS

The ratio of left ventricular weight to body weight was increased in hypertensive rats compared with controls. In control rats, ARIs at the base of both ventricles were shorter than those at the apex. In hypertrophied hearts, ARIs were prolonged on both the left and right ventricular epicardium. Heterogeneous prolongation was observed via reduced apex-to-base differences in ARIs and increased interventricular differences, with a trend toward increasing dispersion of ARIs. In rats with renovascular hypertension, nonuniform prolongation of epicardial ARIs on both ventricles and the changes in the ARI distribution resulted in a reduction of the repolarization time gradient between the ventricles.

CONCLUSION

Nonuniformly prolonged ARIs across the ventricular epicardium and the interventricular electrical inhomogeneity in rats with renovascular hypertension should be considered when interpreting the T wave alterations together with the reduction of the transmural and apex-to-base repolarization gradients.

Sodium Gill Potential as a Tool to Monitor Valve Closure Behavior in Freshwater Clam Corbicula fluminea in Response to Copper

Valve closure behavior in freshwater clam Corbicula fluminea is a biologically sensitive endpoint. The purpose of this paper was to derive an electrophysiological response model of C. fluminea to assess copper (Cu)–sodium (Na) interactions in gill membrane, whereby valve closure behavior and Cu toxicity could be monitored. The proposed model was based on the integration of Cu bioavailability, Na and Cu internalizations, and electrochemically-based gill potentials. Based on Na active transport under non-equilibrium conditions, predicted gill potential of −8.2 mV agreed reasonably well with published the measured transepithelial potential of −7 mV in C. fluminea. Our proposed framework captured the general features observed in model applications including: (i) 50% inhibitory Cu²⁺ activities for Na membrane potential (E_Na) and uptake rate (J_Na) were estimated to be 0.072 and 0.043 μM, respectively, with a stoichiometry of 3Cu²⁺: 1E_Na and 1J_Na; (ii) the external Cu²⁺–dependent internal Na concentration could be parsimoniously estimated, and (iii) the site-specific clam gill potentials could be monitored. Here we provided a new approach to monitor waterborne metal toxicity to reduce the nationwide economic losses due to bans on harvesting of contaminated clam and the potential risks to the health of clams.

Inducibility of atrial tachyarrhythmias after circumferential pulmonary vein isolation in patients with paroxysmal atrial fibrillation: clinical predictor and outcome during follow-up

Aims

We investigated the presence and clinical outcome of inducibility of atrial tachyarrhythmias after circumferential pulmonary vein isolation (CPVI) in patients with paroxysmal atrial fibrillation (PAF).

Methods and results

Sixty patients with symptomatic PAF underwent CPVI guided by 3D mapping and double Lasso technique. After achievement of CPVI, the induction was performed. The left atrium (LA) volume and the isolated LA area around the right and left-sided pulmonary veins were measured by the 3D mapping system. Sustained atrial tachyarrhythmias (>10 min) were induced after CPVI in 17 of 60 patients (28%). Patients with inducible atrial tachyarrhythmias had significantly smaller isolated areas when compared with the group with non-inducible tachyarrhythmias (16.7 ± 2.3 vs. 18.8 ± 2.9%, P < 0.05). After the initial procedure, recurrence occurred in 18 of 43 (42%) patients in the non-inducible group and in 7 of 17 (41%) in the inducible group during follow-up. A repeat procedure was performed in all 25 patients with recurrence. Five patients had a recurrence after the repeat procedure during 20.8 ± 7.5 months, and there was no difference between the two groups.

Conclusion

Inducibility of atrial tachyarrhythmias is associated with proportionally smaller isolated area and does not predict the clinical efficacy of CPVI in patients with PAF.

Processing Anaphoric Constructions: Insights from Electrophysiological Studies

Anaphora is a common, universal, and critical aspect of communication. For quite some time, linguists and psycholinguists have applied introspective and behavioral techniques to the study of anaphora, yielding a large body of evidence and generating a number of theories and models of anaphoric usage and processing. The recent advent of the use of electrophysiological techniques to study language processing creates a unique opportunity to reevaluate these theories and models on the basis of neurophysiological data. This paper examines whether two key characteristics of anaphoric relationships (i.e. the underlying linguistic mechanism and the nature of the anaphor) have observable effects on neurophysiological processing. An exhaustive review of electrophysiological studies testing anaphoric constructions leads to the novel conclusion that the effects of these characteristics are reducible to differences in the time-course of the availability of information and the ability to form expectations about anaphoric relationships. This review also demonstrates that while theories of anaphoric usage are generally supported, finer-grained models of the time-course of anaphoric processing require revision to account for the new electrophysiological data.

Angiotensin I converting enzyme gene polymorphism and exercise trainability in elderly women: an electrocardiological approach

Angiotensin I converting enzyme (ACE) gene Insertion / Deletion (I/D) polymorphism is associated with exercise trainability and exercise induced left ventricular hypertrophy. However, it is unclear whether this polymorphism influences exercise trainability in the elderly, and the electrocardiological alterations by exercise training is unknown among the genotypes. We herein investigated the association between ACE gene insertion/deletion (I/D) polymorphism, exercise trainability and the electrocardiological alternations by exercise in elderly women. Eighty four elderly women participated in this study. In all subjects the leg extension power (LEP) and lactate threshold (LT) were determined in order to evaluate the muscle strength, aerobic capacity and to also select the appropriate training intensity for each individual. They performed bench step exercise training for 12 weeks. A resting electrocardiogram was recorded for the obtained QTc interval in before and after the program. The baseline of aerobic capacity was higher in I/I than that in I/D, and the QTc interval was shorter in I/I than that in I/D. All other characteristics were similar among the genotypes. The QTc interval tended to be shorten only in the D/D. Furthermore, the value of the QTc interval change showed a significant difference between the I/I and D/D genotype after the program. The LT and LEP demonstrated a similar response among the genotypes. The D allele of ACE gene I/D polymorphism may therefore play a role in the electrocardiological aspect during exercise training, however, it was not found to influence the aerobic capacity. Key pointsThe D allele of ACE gene I/D polymorphism may play a role in the electrocardiological aspects during exercise trainingACE gene I/D polymorphism was not determined the aerobic capacity and leg strength in elderly people.The ACE gene I/D polymorphism did not influence aerobic and strength trainability in elderly people.

Can pediatric electrophysiologists safely perform electrophysiology studies on adults with congenital heart disease?

INTRODUCTION

Adults with congenital heart disease (ACHD) are known to have arrhythmias. The purpose of this study was to review the safety and efficacy of a pediatric electrophysiologist performing electrophysiology studies (EPS) on ACHD.

METHODS

All ACHD >18 years of age who underwent an EPS performed by a pediatric electrophysiologist between 1995 and 2004 were included. Patient records were reviewed for demographics, cardiac diagnosis, surgery, arrhythmia, and catheterization issues such as vascular access, fluoroscopy time, complications, procedure performed, and success rates.

RESULTS

The study identified 70 patients who underwent 93 EPS: 42 with ventricular tachycardia (VT) and 28 with supraventricular tachycardia (SVT). With respect to safety, vascular access was obtained in 100% of patients, fluoroscopy time averaged 34.2 minutes, and complications occurred in 3 patients (4%) including permanent (1) or transient (1) atrio-ventricular node injury and coagulum on the catheter (1), but no deaths. With respect to efficacy, 30 patients had an attempted radiofrequency ablation that was successful in 21 of 28 (75%) with SVT and 1 of 2 (50%) with VT.

CONCLUSIONS

(1) ACHD can safely undergo an electrophysiology study performed by pediatric electrophysiologists, with low fluoroscopy times and few complications. (2) Success rates for ablation in this patient population approach 75%.

Prenatal exposure to carbon monoxide temporarily impairs maturation of rat cardiomyocytes: Electrophysiological evidence

BACKGROUND

Maternal smoking is an independent risk factor for sudden infant death syndrome. Carbon monoxide (CO) is a major component of cigarette smoke. No information is available concerning the effect of CO and/or smoking on postnatal maturation of the heart.

OBJECTIVES

To investigate the effect of prenatal exposure to CO on cellular electrophysiological maturation in male Wistar rats.

METHODS

The patch-clamp technique was used to measure the action potential and ionic currents (transient outward current and long-lasting type Ca(2+) current) from rat ventricular myocytes.

RESULTS

During growth, action potential duration (APD) measurements at -20 mV and -50 mV (APD(-20) and APD(-50)) progressively decreased in both groups. APD was significantly delayed in rats prenatally exposed to 150 parts per million CO: at four weeks APD(-20) and APD(-50) were 90 ms and 148 ms, respectively, in CO-exposed rats (n=13), and 36 ms and 78 ms, respectively, in control rats (n=14; P<0.01 and P<0.05, respectively); this normalized at eight weeks. After four weeks, the density of long-lasting type Ca(2+) current increased by 34% and the density of transient outward current decreased by 37% in CO-exposed versus control rats; this normalized at eight weeks.

CONCLUSIONS

Prenatal CO exposure affects the physiological shortening of APD in neonatal rats. It is speculated that prolonged myocyte repolarization induced by prenatal exposure to smoke may establish a period of vulnerability for life-threatening arrhythmias during infancy.

Role of nitric oxide in regulating cardiac electrophysiology

Despite the explosion of new information on nitric oxide (NO), important questions about its role in regulating cardiac electrophysiology remain unanswered. Recent in vitro and in vivo animal studies have discovered a number of new electrophysiological properties of NO, some of which may contribute to a reduction in fatal arrhythmias induced by acute myocardial ischemia. This review summarizes the influences of NO on heart rate, atrioventricular conduction, ventricular repolarization and the development of ventricular arrhythmias during acute myocardial ischemia.

Effect of muscarinic blocker on enhancing the action of fructus aurantii immaturus on intestinal myoelectric activity in dogs

AIM: To investigate the effect of fructus aurantii immaturus (FAI) on small intestinal electrical activity in dogs.

METHODS: The effect of FAI was observed using a computerized electrophysiological method with the migrating myoelectric complex as a criterion. Fasted, healthy, and conscious dogs were given 100% FAI concentrated solution by gastrostogavage, and as soon as the effect on small intestinal electrical activity appeared, atropine was injected intramuscularly.

RESULTS: The enhancing action of FAI was inhibited significantly by atropine, a cholinergic receptor antagonist. Both the number of spike bursts per cluster and the number of spikes per minute in phase II and III and the general cycle were decreased (P < 0.01), although the duration of phase II and the general cycle was prolonged.

CONCLUSION: The effect of FAI might be related to the muscarinic receptors.

Study of the regulatory effect of acupuncture on rotation-induced gastric dysrhythmia in rabbits

AIM: A model of experimental gastric dysrhythmia in rabbits was set up to evaluate the effect of different acupoints on regulating gastric dysrhythmia in rabbits so as to promote acupuncture treatment for this kind of disease.

METHODS: A model of gastric dysrhythmia in rabbits was established by the rotation method using the basic electrical rhythm (BER) as an objective index. After puncturing at the points of Zusanli (ST36), Neiguan (PC6), Tiaokou (ST38) and Tianquan (PC2) in the four groups of experimental gastric dysrhythmia rabbits, the difference in regulatory effects on the disturbance and frequency of the gastric electric slow wave was observed.

RESULTS: Before needling at the specific acupoints Zusanli and Neiguan, the percentage of disturbance electric slow wave for the Zusanli and Neiguan groups was 57.0785 ± 10.644 and 55.5173 ± 6.0500, respectively; after such needling, the percentage was 43.7823 ± 10.1518 and 43.5147 ± 6.8983 for the Zusanli and Neiguan groups, respectively, while the frequency of electric slow wave for the Zusanli and Neiguan groups was 2.2870 ± 0.3800 and 2.4020 ± 0.3536, respectively, before needling and after needling, the frequency was 2.7090 ± 0.5865 and 2.9220 ± 0.4923 for the Zusanli and Neiguan groups, respectively. Comparing the percentage and frequency for the Zusanli and Neiguan groups before and after needling, the result shows that both groups have a significant difference statistically (P < 0.05) but between the Zusanli and Neiguan groups, there was no significant difference. Before and after needling the nonspecific acupoints of Tiaokou and Tianquan, there was no difference between the Tiaokou and Tianquan groups. Between the Zusanli and Tiaokou groups and the Neiguan and Tianquan groups, there are significant differences in regulating gastric dysrhythmia.

CONCLUSION: This model is suitable for the observation of gastric dysrhythmia. The specific acupoints of Zusanli and Neiguan have good effects on the treatment of gastric dysrhythmia.