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PubMed1983

[Pharmacological investigation of rotational behaviors produced by unilateral electrical stimulation of the substantia nigra in the rat].

In order to elucidate pharmacological properties of rotational behaviour produced by unilateral electrical stimulation of the substantia nigra, effects of 6-hydroxydopamine treatment, dopamine receptor antagonists and agonists were investigated in the rat. Dopamine and its metabolites in the striatum were estimated after the stimulation. Intranigral treatment of 6-hydroxydopamine remarkably inhibited rotational behaviour induced by electrical stimulation. Antipsychotic drugs, 1 mg/kg haloperidol i.p. and 1 mg/kg pimozide i.p., decreased the behaviour by 50% of the control level. Sulpiride and metoclopramide did not exert significant influences on the behaviour. The dopamine receptor agonist apomorphine, 0.5 and 1 mg/kg s.c., markedly suppressed the stimulation-induced rotation, although it produced stereotypy, i.e. sniffing and gnawing. Bromocriptine, 10 mg/kg i.p., also suppressed rotational behaviour and produced locomotor activation without electrical stimulation. Methamphetamine did not have significant effects on the behaviour. Unilateral electrical stimulation of the substantia nigra produced an increase in the content of dopamine metabolites in the ipsilateral striatum of the rat pretreated with probenecid. These results suggest that the nigrostriatal dopaminergic system plays an important role in rotational behaviour produced by the electrical stimulation, and dopamine receptor agonists suppress the behaviour through a stimulating effect on the presynaptic dopamine receptor.

3,4-Dihydroxyphenylacetic Acid↗

PubMed1998

The effects of superimposed electrical stimulation of the quadriceps muscles on performance in different motor tasks.

BACKGROUND: Some examples are presented to show how superimposed electrical stimulation of muscles during maximum voluntary effort can be used to enable subjects to achieve greater joint torque, rate of joint torque development, and the joint angular velocity as when performing only voluntarily with maximum effort. METHODS PARTICIPANTS: Ten students of physical education not involved into a regular sport training participated the study. INTERVENTIONS: The subjects performed isometric and concentric knee extensions and squat jumps, without and with superimposed electrical stimulation of the quadriceps muscles. MEASURES: A knee torque and angular displacement were observed during isometric and concentric knee extension. During the jumping, a vertical component of the ground reaction force was measured. RESULTS: Results showed that the maximal knee torque, as well as a torque rise, were higher in isometric knee extension trials with superimposed electrical stimulation. The same was observed in concentric knee extensions, where greater knee torque during superimposed electrical stimulation also resulted in higher angular velocity and a more extended knee at the end of the movement. In squat jumps, the application of the superimposed electrical stimulation resulted in poorer performance. CONCLUSIONS: It was concluded that superimposed electrical stimulation was effective in some simple motor tasks, but not in more complex tasks where a co-ordination of multiple muscles of different groups was necessary for improved performance.

Acceleration↗

PubMed2006

Gentamicin abolishes all cochlear effects of electrical stimulation of the inferior colliculus.

Electrical stimulation of the inferior colliculus (IC) has been shown to result in suppression of cochlear output, due to activation of the medial olivocochlear system. This auditory efferent system originates in the brainstem and terminates on the outer hair cells in the cochlea. Recently, excitatory effects of IC stimulation have also been reported, both on cochlear gross potentials and on primary auditory afferents. It has been hypothesized that this excitation is due to co-activation of the lateral olivocochlear system, which synapses on the primary auditory afferent fibres contacting the inner hair cells. If stimulation of the IC leads to the activation of both the medial and lateral olivocochlear system, resulting in a mixture of inhibitory and excitatory effects in the cochlea, then removal of the inhibitory effects, by blocking the medial system, should lead to more pronounced excitatory effects out in the periphery. To investigate this hypothesis, we recorded the effect of IC stimulation on cochlear gross potentials as well as on single auditory primary afferents in guinea pigs following block of the medial olivocochlear system with gentamicin. We found that administration of gentamicin, whether intraperitoneally or by intracochlear perfusion, blocked all effects of IC stimulation, whether inhibitory or excitatory. These data strongly suggest that all effects observed after IC stimulation, both inhibitory as well as excitatory, are due to the activation of the medial olivocochlear system.

Acoustic Stimulation↗

PubMed1979

Facilitated healing of osseous lesions in the canine mandible after electrical stimulation.

A study was performed to investigate the effect of electrical stimulation on the repair of osseous lesions in the canine mandible. Results showed considerably more osteoblastic activity on the electrically stimulated side, with maximal growth nearest the negative electrode. Histologic examination showed healing consisted of the production of intramembranous bone, with no evidence of neoplastic changes. The practical uses of electrical stimulation in the practice of oral and maxillofacial surgery are discussed.

Animals↗

PubMed2006

Somatosensory function following painful repetitive electrical stimulation of the human temporomandibular joint and skin.

Temporomandibular disorders (TMD) are common pain problems in the population with uncertain pathophysiology and mechanisms. The aim of this experimental study was to: (1) Establish an experimental pain model using electrical stimuli to describe characteristics of nociception from the human temporomandibular joint (TMJ) and overlying skin. (2) Test the hypothesis that there would be sex-related differences in TMJ sensitivity. Forty-three healthy subjects (24 men and 19 women) participated. Using two unipolar needle electrodes into the skin (above the TMJ) in one session or into the TMJ in the other session, sensory detection threshold (SDT), pain detection threshold (PDT), and summation threshold (SumT) were measured, before and after repetitive electrical stimulation. Painful repetitive electrical stimulation was applied for 20 min with individually adjustment of the intensity of the stimuli to keep the pain rating around five on a 0-10 cm visual analogue scale (VAS). Sensitivity to tactile and pin-prick stimuli were assessed at 11 sites around the TMJ using two von Frey nylon filaments (5.16 and 84.96 g), as well as pressure pain threshold (PPT) and pressure pain tolerance (PPTOL) before the stimulation, after 20 min of stimulation and finally 15 min after the end of stimulation. Numerical rating scale (NRS) from 0 to 100 was used to rate the intensity of applied von Frey filaments. SDT, PDT, and SumT were higher in the TMJ than in the skin. These three measures increased after painful repetitive stimulation for 20 min (de-sensitization). In contrast to this effect, a hypersensitivity to pin-prick stimuli was detected around the TMJ area on the stimulated side after 20 min of electrical stimulation in the TMJ, but not in the skin. A bilateral hyposensitivity to tactile stimuli was detected after skin and TMJ stimulation. PPT and PPTOL did not show a significant change over time. Except for lower TMJ PPTOLs in women than men there were no significant sex-related differences in mechanical or electrical measures. The present findings indicate differences in the elicitation of hypersensitivity following repetitive electrical stimulation of skin and deep tissues. The mechanisms underlying these findings are not clear but differences in the induction of long-term potentiation and depression is a possibility. From a clinical point of view, the lack of sex differences in most of the used measures indicates that the higher prevalence of women than men amongst patients with persistent TMJ pain problems not entirely can be ascribed to a higher sensitivity of the TMJ. Further studies will examine the somatosensory sensitivity of patients with TMJ pain problems.

Adult↗

PubMedDate not supplied

The effect of thigh muscle reconditioning by electrical stimulation on urodynamic activity in SCI patients.

Various forms of electrical stimulation are being used more frequently for bladder and muscle rehabilitation following spinal injury. Fifteen patients with spinal cord injury underwent a four to eight week period of thigh muscle reconditioning by surface electrical stimulation. The accumulated effects of this program on bladder function were assessed by urodynamic evaluation before and after the test period. Seven patients had beneficial changes of either an increase in bladder capacity and/or a decrease in bladder pressure. Six patients had a decrease in bladder capacity and/or an increase in bladder pressure, although two of these six patients had resolution of spinal shock. Two patients with detrusor areflexia had no changes in pressure or capacity. There was no change in the basic urodynamic patterns, only the parameters of bladder capacity and pressure. Increasing the use of electrical stimulation for rehabilitation of the spinal cord population might alter bladder function, although not consistently. One should, therefore, be aware of these changes when setting up such rehabilitation programs.

Adult↗

PubMed1994

Effects of gastric distension and electrical stimulation of dorsomedial medulla on neurons in parabrachial nucleus of rats.

The effects of gastric distension and electrical stimulation of the dorsomedial medulla on neurons within the parabrachial nucleus (PB) were investigated electrophysiologically in urethane-chloralose anesthetized rats. Among 74 neurons tested, electrical stimulation of the nucleus of the solitary tract (NTS) excited 30 neurons (excitatory neurons) and inhibited 14 neurons (inhibitory neurons). Fourteen neurons increased and 12 neurons decreased their discharge rates in response to gastric distension. Twenty-two neurons responded to both electrical stimulation of the NTS and gastric distension. Both excitatory and inhibitory neurons showed either an increase or a decrease in discharge rate responding to gastric distension. Furthermore, three neurons that decreased their discharge rates and two neurons that increased their discharge rates during gastric distension also responded to intravenous administration of metaraminol indicating some effect of baroreceptor activation on the neural activity. The responses of another 49 neurons in the PB to electrical stimulation of area postrema and gastric distension were analyzed. Electrical stimulation of the AP excited 14 neurons and inhibited only one neuron. Five neurons increased and seven neurons decreased their discharge rates in response to gastric distension. Only one inhibitory neuron responded to gastric distension. These observations suggested that the PB neurons received gastric mechanoreceptive inputs from the NTS.

Animals↗

PubMed1980

[Increased food motivation in rabbits during prolonged automatic electric stimulation of lateral hypothalamic structures].

An automatic electric stimulation elicited a long-term focus in food motivation centers in rabbits, whose food-getting instrumental activity, EEG and some vegetosomatic parameters were studied. The focus induced the epileptiform EEG activity spreading from the hypothalamus up to the cerebral cortex. The food instrumental responses were either abruptly intensified or inhibited depending on the electrode localization. After cessation of the electric stimulation the focus remained without any sign of fading for one month.

Animals↗

PubMed1996

[Effects of chronic electrical stimulation on cochlear nuclear neuron size in deaf kittens].

It is now well recognized that normal afferent innervation is necessary for development of the auditory pathway. This study investigated the effect of chronic electrical stimulation of the auditory nerve on the size of cochlear nucleus somata of neonatally deafened kittens. Four kittens were deafened by using kanamycin and ethacrynic acid at 10 days of age and implanted at various ages with an active intracochlear implant in the left side and a dummy implant in the right side, and chronically electrically stimulated from ages 98-142 days for approximately 1000 hours at twice the EABR threshold. After chronic stimulation or after an equivalent period in the controls, the animals were injected with 2-deoxyglucose (2DG) and stimulated electrically for 45 minutes, then processed for autoradiography. Then the sections were stained for Nissle substance, and the cross-sectional areas (CSSA) of approximately 33,000 neuron somata in the cochlear nuclei were measured with an image-analysis system. Soma sizes in regions with 2DG uptake were compared with those without the uptake. The CSSA of 2DG-labeled regions was usually significantly larger than that of the unlabeled regions, but there were no significant right-left differences. Thus, chronic electrical stimulation of a restricted sector of the cochlea is correlated with a larger soma size in the corresponding region of the cochlear nucleus.

Animals↗

PubMed2005

Full-thickness burn formation after the use of electrical stimulation for rehabilitation of unicompartmental knee arthroplasty.

Electrical stimulation and interferential current are commonly used modalities in the physical rehabilitation of patients who have undergone joint arthroplasty surgery. Sparse data are available in the literature regarding potential complications from using these modalities. We report on a patient who underwent a unicompartmental knee arthroplasty with a subsequent full-thickness skin burn over the metal implant after electrical stimulation and interferential current modalities in physical therapy.

Arthroplasty, Replacement, Knee↗

PubMed1976

Mechanism of lipolysis induced by electrical stimulation of the hypothalamus in the rabbit.

Electrical stimulation of the ventro-medial hypothalamus of the rabbit elevated plasma glycerol concentration. This elevation was suppressed by treatments of the animals with hexamethonium and propranolol, or by adrenalectomy, but was not suppressed by treatments with atropine and phentolamine. These results would indicate that the effect of electrical stimulation of ventro-medial hypothalamus is mainly mediated by catecholamine(s) liberated from the adrenal medulla and acts on beta-receptor of adipose tissue.

Animals↗

PubMed1991

The effect of electrical stimulation on the number of mast cells in healing wounds.

Many cutaneous disorders are associated with activation or increased numbers of mast cells. Electrical stimulation has been shown to be effective in treating many of these disorders. This study is designed to examine the effect of electrical stimulation on mast cells in acute wounds. Four pathogen-free pigs received 20 wounds, each of which was subjected to biopsy at various times after wounding. Half of the wounds were treated with electrical stimulation and the other half were treated with a sham electrode. The biopsy specimens were fixed in Carnoy's medium and stained with alcian blue and Nuclear Fast Red. Mast cells from both sets of wounds were counted and analyzed. Highly significant reductions in the number of mast cells were seen with electrical stimulation on days 1 and 2 compared with nonstimulated control wounds. Electron microscopy was performed to compare the stimulated and control mast cells for characteristic features in morphology, location, and evidence of degranulation. Electrical stimulation did not appear to induce degranulation. The ability of electrical stimulation to decrease the number of mast cells may be related to a reduction of either proliferation or migration of these cells and may prove to be a valuable therapeutic technique.

Animals↗

PubMed1993

Electrical stimulation to modify detrusor function.

Electrical stimulation to modify detrusor function is now being used in humans. The sacral foramen electrode is currently the only implantable device used to inhibit bladder contractility. Stimulation of a bladder contraction requires electrode placement around the anterior sacral root. Dorsal rhizotomy, preferably performed intradurally, is necessary to abolish detrusor hyperreflexia, thus increasing functional bladder capacity. Stimulation of the anterior sacral root then results in detrusor contraction.

Electric Stimulation Therapy↗

PubMed1978

[Electric stimulation in the treatment of chronic pain].

Electrical stimulation in the treatment of chronic pain, though an old method, has become very attractive again in the last ten years. The use of transcutaneous, percutaneous and implanted stimulating devices is discussed. Although the method is sometimes contested and the mechanism of action not yet clear, it can no longer be ignored. Even if the clinical successes are in the long run only limited, the application of the method must be considered. If only one in three or four patients is still painfree after a few years by the use of an implanted electrical stimulating device, it is a tremendous boon for this particular patient when all other kinds of conservative and surgical treatment have failed.

Afferent Pathways↗

PubMed2005

Influence of electrophysiological heterogeneity on electrical stimulation in healthy and failing human hearts.

The application of strong electrical stimuli is a common method used for terminating irregular cardiac behaviour. The study presents the influence of electrophysiological heterogeneity on the response of human hearts to electrical stimulation. The human electrophysiology was simulated using the ten Tusscher-Noble-Noble-Panfilov cell model. The anisotropic propagation of depolarisation in three-dimensional virtual myocardial preparations was calculated using bidomain equations. The research was carried out on different types of virtual cardiac wedge. The selection of the modelling parameters emphasises the influence of cellular electrophysiology on the response of the human myocardium to electrical stimulation. The simulations were initially performed on a virtual cardiac control model characterised by electrophysiological homogeneity. The second preparation incorporated the transmural electrophysiological heterogeneity characteristic of the healthy human heart. In the third model type, the normal electrophysiological heterogeneity was modified by the conditions of heart failure. The main currents responsible for repolarisation (Ito, IKs and IKI) were reduced by 25%. Successively, [Na+]i was increased by the regulation of the Na+-Ca2+ exchange function, and fibrosis was represented by decreasing electrical conductivity. Various electrical stimulation configurations were used to investigate the differences in the responses of the three different models. Monophasic and biphasic electrical stimuli were applied through rectangular paddles and needle electrodes. A whole systolic period was simulated. The distribution of the transmembrane voltage indicated that the modification of electrophysiological heterogeneity induced drastic changes during the repolarisation phase. The results illustrated that each of the heart failure conditions amplifies the modification of the response of the myocardium to electrical stimulation. Therefore a theoretical model of the failing human heart must incorporate all the characteristic features.

Electric Countershock↗

PubMed1999

Treatment of tinnitus with electrical stimulation.

The purpose of this study was to evaluate the treatment of tinnitus with electrical stimulation. Five hundred patients with tinnitus were treated with probe electrical stimulation. Causes of tinnitus were sensorineural hearing loss (303 patients), Meniere's disease (88), infection (25), head trauma (39), acoustic trauma (25), ototoxicity (4), and chemotherapy (2). Treatment involved 6 to 10 transcutaneous treatment electrical stimulation sessions biweekly. Fifty-three percent of patients showed decreases in their tinnitus as measured by a subjective rating scale. With a 3-month follow-up, 72% had no loss of benefit. Thirteen patients had temporary increases in their tinnitus. Two patients had permanent increases. Probe electrical stimulation seems to offer some benefit in about half the patients treated for annoying tinnitus.

Adult↗

PubMed1993

[Cochlear histopathological changes following chronic extracochlear electrical stimulation in kittens].

Histopathological investigation of the cochlea following chronic extracochlear electrical stimulation was carried out in 5 kittens. The auditory nerves were electrically stimulated with round window or tympanic promontory electrodes for periods of 1276-1526 h using charge-balanced biphasic current pulses at charge densities of 1.27-5.73 microC/cm2. geom. phase. The histopathological changes were examined with a light microscope. The findings were as follow: 1. The fixations of round window and tympanic promontory electrodes were very firm. Six round window membranes became thicker in the area which contacted the electrode. One was pushed into the scala tympani and adhered to the spiral lamina of the hook region. 2. There was some outer hair cell loss, mild inner hair cell loss and disappearance of Corti's organ structures in a small area of lower basal turns. 3. Decrease of spiral ganglion cell density was found over a 2% basilar membrane length in 2 stimulated cochleas. 4. There was no change in normal control cochleas. These results indicate that mild histopathological changes occurred even though chronic electrical stimulation was performed with non-invasive extracochlear electrodes. The mechanism behind these changes should be further investigated.

Animals↗

PubMed2006

The therapeutic effect of functional and transcutaneous electric stimulation on improving gait speed in stroke patients: a meta-analysis.

OBJECTIVE: To determine the effect of previous treatments of functional electric stimulation (FES) and transcutaneous electric stimulation (TENS) on improving gait speed in subjects poststroke. DATA SOURCES: Relevant articles were obtained through a search of English-language articles cited in Medline, EMBASE, CINHAL, and PubMed databases from January 1966 to May 2005. STUDY SELECTION: Prospective clinical studies were included if electric stimulation was used to treat subjects poststroke and gait speed was used as an outcome measure. Excluded studies examined subjects with a variety of neurologic conditions, used implantable electrodes, or combined electric stimulation with treadmill training. A paired consensus between authors produced 8 articles. DATA EXTRACTION: Two investigators extracted data independently. The methodologic quality of the studies was assessed with the Downs and Black checklist. DATA SYNTHESIS: A fixed-effects model produced a mean difference (.18; 95% confidence interval, .08-.28) that was significant (z=3.65, P<.01), indicating the effectiveness of FES treatment at increasing gait speed in subjects poststroke. The effect sizes of the studies ranged from -.11 to 1.43 for FES and .19 to .42 for TENS. The type of FES and TENS devices, location of electrodes, amount of exposure, and subjects' stages of recovery varied between the studies. CONCLUSIONS: FES is effective at improving gait speed in subjects poststroke. Future research should examine the effectiveness of practical and readily available FES units to improve function in subjects in the subacute stages of recovery from a stroke. These studies should attempt to use a randomized controlled design with blinding and standardized outcome measures.

Gait Disorders, Neurologic↗