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PubMed1983

Suppression of lordotic responsiveness in the female rat during mesencephalic electrical stimulation.

The effects of biphasic electrical stimulation of the mesencephalic median (MRN) and dorsal raphe (DRN) nuclei, as well as the adjacent periaqueductal gray (PAG), on lordotic behavior were investigated in ovariectomized rats primed with three daily injections of estradiol benzoate (2 micrograms). Animals were tested between 4-8 hours after a progesterone (0.5 mg) injection on day four which normally facilitates high levels of receptivity during this period. Although stimulation of the MRN had no significant effect on lordosis, DRN activation at 100 Hz (0.5 msec pulse duration) or 10 Hz (2 msec pulse duration) caused a marked and immediate suppression (53% and 56%, respectively) in receptivity. This suppression does not appear to be due to activation of serotoninergic neurons originating in the DRN since pretreatment with an inhibitor of serotonin synthesis (parachlorophenylalamine, 320 mg/kg) essentially did not modify the suppression, thus providing no evidence in support of an inhibitory role for serotonin in lordotic behavior. Activation within the PAG adjacent to the DRN at 10 Hz (0.5 or 2 msec pulse duration) produced an immediate, dramatic decrease (81% and 80%, respectively) in receptivity. The suppressions induced by DRN and PAG stimulation appear most likely to be due to activation of a descending pathway inhibitory to the lordosis reflex at medullary or spinal cord levels.

Animals↗

PubMed1990

Effect of electrical stimulation on intracellular triacylglycerol in isolated skeletal muscle.

The contribution of intracellular triacylglycerol (TG) as a substrate for skeletal muscle during electrical stimulation is equivocal. Therefore, the purpose of this study was to investigate the effect of electrical stimulation on the TG content in the isolated intact rat flexor digitorum brevis skeletal muscle preparation by use of two different stimulation protocols. Muscles were electrically stimulated for 1 h either continuously at 1 Hz or intermittently (30 s on, 60 s off) at 5 Hz while incubated in 21 degrees C Krebs bicarbonate buffer (pH 7.4) that contained 11 mM glucose. Control muscles were either frozen immediately after excision or incubated for 1 h. TG content was significantly decreased (P less than 0.05) compared with control concentrations in both stimulated muscle groups, with the greatest reduction (60%) occurring after 5-Hz intermittent stimulation. These data indicate that intramuscular TG is hydrolyzed in response to electrical stimulation in the isolated flexor digitorum brevis muscle preparation. In addition, the type of stimulation (higher frequency intermittent vs. lower frequency continuous) employed influences the amount of intracellular TG hydrolyzed.

Animals↗

PubMed1993

Acute electrical stimulation increases extramyocardial collateral blood flow after a cardiomyoplasty.

We hypothesized that acute electrical stimulation of a latissimus dorsi cardiomyoplasty would augment the collateral blood flow delivered by the skeletal muscle to the heart. This hypothesis was tested in an animal model (13 goats) of coronary artery disease. Six weeks after a cardiomyoplasty was performed, myocardial collateral blood flow derived from the latissimus dorsi muscle was measured with colored microspheres when the muscle was at rest and during electrical stimulation of the thoracodorsal nerve at 1.25 Hz. The area at risk for ischemia averaged 13.37 +/- 2.08 g (mean +/- standard error), or 18.4% of left ventricular mass (n = 13). At rest, significant skeletal muscle-derived collaterals developed in 9 animals, and formed predominantly to chronic ischemic myocardium (mean +/- standard error, 0.07 +/- 0.02 mL.g-1 x min-1; n = 9), rather than infarct (0.03 +/- 0.02 mL.g-1 x min-1; n = 5), or normal myocardium (0.0005 +/- 0.0001 mL.g-1 x min-1; n = 9). Stimulation increased skeletal muscle-derived collateral blood flow to chronic ischemic areas to 0.38 +/- 0.09 mL.g-1 x min-1 (n = 9) (p < 0.05). During stimulation, the collateral flow was greater in the epicardium (0.46 +/- 0.11 mL.g-1 x min-1) than in endocardium (0.14 +/- 0.09 mL.g-1.min-1) (p < 0.05). This study demonstrates that electrical stimulation of a latissimus dorsi cardiomyoplasty increases extramyocardial collateral blood flow to chronic ischemic myocardium.

Animals↗

PubMed2001

Descending and ascending spinal cord evoked potentials from oesophago-vertebral electrical stimulation in normal awake man.

Electrical stimulation of the spinal cord at C7D1 evoked triphasic descending spinal cord evoked potentials (DSCEP) from an oesophago-vertebral recording at D8D8 or D1OD1O. Ascending SCEPs (ASCEP) larger and similar in shape were also observed when the orientation of the stimulating and recording dipoles was reversed. Both SCEPs are in part generated by descending and ascending synchronous excitation of neuronal volume-conducted spinal cord dipoles.

Adult↗

PubMedDate not supplied

Is there a role for ultrasound and electrical stimulation following injury to tendon and nerve?

Ultrasound (US) and electrical stimulation have been widely used in hand therapy to promote recovery after nerve and tendon injuries. There is support for the use of low-dosage continuous wave and pulsed US for carpal tunnel syndrome and tendonitis. Iontophoresis with dexamethasone sodium phosphate can relieve pain in acute elbow tendonitis, but there is no support for phonophoresis for any tendonitis. Animal model research supports the use of low-dosage US to improve the mechanical properties of the Achilles tendon when initiated immediately after tenorrhaphy. There are no studies available which have examined US applied to tendons in humans after repair. Electrical stimulation has been extensively studied in animal models after nerve axonotmesis and neurotmesis with nerve repair, with some support of enhancing recovery. There is a void in the literature on the use of electrical stimulation for humans after nerve transection and repair.

Electric Stimulation Therapy↗

PubMed1981

Two different biophases for adrenaline released by electrical stimulation or tyramine from the sympathetic nerve endings of the dog saphenous vein.

To study the distribution of alpha- and beta-adrenoceptors dog saphenous vein strips were electrically stimulated (2ms, 30 V, 0.25--20 Hz). The strips either had spontaneous tone (contraction experiments) or were contracted by 0.28 microM prostaglandin F2 alpha in the presence of 7 microM phentolamine (relaxation experiments). In strips without preloading or in strips preloaded with (--)-noradrenaline alpha-adrenoceptor-mediated excitatory responses were readily evoked (contraction experiments) but not beta-adrenoceptor-mediated inhibitory responses (relaxation experiments). In strips preloaded with (--)-adrenaline both alpha-(contraction experiments) and beta-effects (relaxation experiments were readily elicited by electrical stimulation and by tyramine. Thus, strips preloaded with (--)-adrenaline were used to compare alpha- with beta-effects. In these strips the latency between the beginning of the electrical stimulation and the onset of the response was longer for beta- than for alpha-responses. The same applies to responses to exogenous (--)-adrenaline. However, the ratio "latency for beta-/latency for alpha-responses" was 3.6 +/- 0.2 (n = 8) for responses to electrical stimulation and 1.8 +/- 0.1 (n = 12) for responses to (--)-adrenaline (P less than 0.001). Cocaine (12 microM) enhanced the alpha-effect elicited by electrical stimulation 2.8 +/- 0.2 (n = 7) times but did not change the beta-effect, whereas U-0521 (50 microM) enhanced the beta-effect 3.4 +/- 0.2 (n = 8) times without changing the alpha-effect. In strips preloaded with (--)-adrenaline also tyramine caused concentration-dependent beta-responses (relaxation experiments). The concentration of phentolamine and prazosin required to inhibit contractions caused by electrical stimulation were about 5--7 times higher than those required to inhibit contractions caused by exogenous adrenaline or noradrenaline, whereas propranolol was equipotent in reducing beta-responses to adrenaline released by electrical stimulation and to exogenous adrenaline. Our results strongly support the view that alpha-adrenoceptors are in close contract with the nerve endings and beta-adrenoceptors are in close proximity of COMT in a vessel with the nerve endings evenly distributed throughout the media.

Animals↗

PubMed1985

Changes in histochemical profile of muscle after long-term electrical stimulation in patients with idiopathic scoliosis.

Adolescent patients with idiopathic scoliosis were treated with long-term electrical stimulation (30 Hz) at the posterior axillary line on the convex side of the curvature in order to correct the spinal deformity. The patients were also followed with muscle biopsies from the latissimus dorsi of the stimulated side taken before, after 3 and 6 months of electrical stimulation. There was a tendency for an increase in the percentage of type I and especially the type II C (undifferentiated) fibers after stimulation. The mean muscle fiber area and the fiber areas of the various fiber types did not change significantly. Histopathological findings were generally rare before as well as after 3 months of electrical stimulation, the only noticeable finding being a somewhat increased frequency of atrophic fibers in groups after 6 months of stimulation. In all studied patients the enzymatic activity of citrate synthase increased after 3 months and further in three studied patients after 6 months of stimulation. The present study gives some evidence of an adaptive process caused by electrical stimulation towards a more fatigue-resistant muscle.

Adenylate Kinase↗

PubMed1982

Improvement of some abnormal motor functions by electrical stimulation.

Clinical results obtained from electrical stimulation of muscle, nerve, spinal cord, cerebellum, and cerebrum are surveyed. Some more data are presented from our own experience with stimulating denervated muscle and cerebellum. Mechanisms which might be responsible for its clinical effects on the muscle, synapse, or nervous system are discussed.

Cerebellar Cortex↗

PubMed2001

Conditioned antinociception and freezing using electrical stimulation of the dorsal periaqueductal gray or inferior colliculus as unconditioned stimulus are differentially regulated by 5-HT2A receptors in rats.

RATIONALE: Electrical stimulation of the dorsal periaqueductal gray matter (dPAG) and the inferior colliculus (IC) has been used as an aversive unconditioned stimulus. However, studies on the behavioral, sensorial and autonomic components of the conditioned fear elaborated in the midbrain tectum are lacking. OBJECTIVES: This study was undertaken to investigate the nature of the aversiveness of stimulation of the dPAG and IC as well as the modulation by 5-HT mechanisms of the fear conditioned responses to these stimulations. METHODS: Animals chronically implanted with an electrode glued to a guide cannula into the dPAG or the IC were submitted to one, two or three sessions of conditioning. Each session consisted of ten pairings of the light in a distinctive chamber (CS) with the electrical stimulation of one of these regions at the escape threshold determined previously. Control groups were submitted to the same procedure, except for the conditioning sessions in which the conditioned stimuli were presented alone in one case and performed in a different context in the other. On the next day, each animal was exposed only to the CS (testing) and the duration of freezing, number of rearings, grooming, bouts of micturition and fecal boli were recorded for 5 min. Before and after the testing session, the animals were submitted to the tail-flick test. RESULTS: The data showed that the conditioning with electrical stimulation of the dPAG and the IC caused significant increases in the time of freezing, defecation and micturition, and significant reductions in the number of rearings and grooming. On the other hand, only the conditioning with electrical stimulation of the dPAG produced significant conditioned antinociception. Microinjections of methysergide, a non-specific antagonist of 5-HT receptors, or ketanserin, an antagonist of 5-HT2A receptors, into the dPAG before testing significantly inhibited the antinociception without affecting any of the behavioral or autonomic conditioned responses. CONCLUSIONS: 1) Conditioned freezing may be produced using the electrical stimulation of the dPAG or IC as unconditioned stimuli, 2) only the pairing of CS plus dPAG but not with IC stimulation, produces significant conditioned antinociception, 3) blockade of 5-HT2A receptors inhibits conditioned antinociception but not the conditioned defensive behavior using the electrical stimulation of the dPAG as unconditioned stimulus.

Animals↗

PubMed1981

Antihistamine-sensitive vasodilatation in the canine hindlimb evoked by electrical stimulation rostral to the hypothalamus.

Electrical stimulation was carried out at various sites in the brain of anaesthetized dogs pretreated with guanethidine. Stimulation at some sites elicited cholinergic vasodilator responses in the femoral vascular bed while stimulation at other sites produced non-cholinergic vasodilator responses which were prevented by histamine antagonists administered into the hindlimb. The central sites mediating the two types of responses were anatomically distinct.

Animals↗

PubMed2002

High voltage electrical stimulation of the proximal hypoglossal nerve in normal subjects.

OBJECTIVES: It is often difficult to stimulate the proximal hypoglossal nerve by magnetic occipital stimulation, even in normal subjects. Therefore, we tested an improved method of stimulating the proximal hypoglossal nerve, using high voltage electrical stimulation. METHODS: The proximal hypoglossal nerve was activated by high voltage electrical stimulation using surface electrodes over the occipital skull. The compound muscle action potential (CMAP) was recorded from the lingual muscles using surface electrodes in 10 normal subjects. CMAP and F waves produced by distal hypoglossal nerve stimulation and motor evoked potentials produced by transcranial magnetic stimulation were also recorded. RESULTS: When the anode electrode was placed at the mastoid process and the cathode below the inion, the unilateral proximal hypoglossal nerve was readily stimulated supramaximally in all the subjects. The CMAP latency was the same as that obtained with magnetic occipital stimulation. The central motor conduction time (CMCT) calculated from the proximal CMAP was 4.1+/-0.4 ms in the contralateral corticobulbar tract and 4.4+/-0.4 ms in the ipsilateral. The CMCT calculated from the minimal F wave latency was 3.3+/-0.2 ms. CONCLUSIONS: The high voltage electrical stimulation is a useful method for stimulating the proximal hypoglossal nerve to estimate the CMCT of the corticobulbar tract.

Adult↗

PubMed1998

Increase of extracellular glutamate and expression of Fos-like immunoreactivity in the ventral tegmental area in response to electrical stimulation of the prefrontal cortex.

Electrical stimulation of the medial prefrontal cortex caused glutamate release in the ventral tegmental area (VTA) of freely moving animals. Cathodal stimulation was given through monopolar electrodes in 0.1-ms pulses at an intensity of 300 microA and frequencies of 4-120 Hz. Glutamate was measured in 10-min perfusate samples by HPLC coupled with fluorescence detection following precolumn derivatization with o-phthaldialdehyde/beta-mercaptoethanol. The stimulation-induced glutamate release was frequency dependent and was blocked by the infusion of the sodium channel blocker tetrodotoxin (10 microM) through the dialysis probe. The stimulation also induced bilateral Fos-like immunoreactivity in ventral tegmental neurons, with a significantly greater number of Fos-positive cells on the stimulated side. These findings add to a growing body of evidence suggesting that the medial prefrontal cortex regulates dopamine release in the nucleus accumbens via its projection to dopamine cell bodies in the VTA.

Animals↗

PubMed1992

[A comparison of time resolution among auditory, tactile and promontory electrical stimulation--superiority of cochlear implants as human communication aids].

Our previous reports showed that second formant information, using a speech coding method, could be transmitted through an electrode on the promontory. However, second formant information can also be transmitted by tactile stimulation. Therefore, to find out whether electrical stimulation of the auditory nerve would be superior to tactile stimulation for our speech coding method, the time resolutions of the two modes of stimulation were compared. The results showed that the time resolution of electrical promontory stimulation was three times better than the time resolution of tactile stimulation of the finger. This indicates that electrical stimulation of the auditory nerve is much better for our speech coding method than tactile stimulation of the finger.

Cochlea↗

PubMed1994

Use of electrical stimulation to enhance recovery of quadriceps femoris muscle force production in patients following anterior cruciate ligament reconstruction.

BACKGROUND AND PURPOSE: Electrical stimulation has been shown to be effective in aiding the recovery of quadriceps femoris muscle force production after anterior cruciate ligament reconstruction. The actual dosage of stimulation (training intensity) has not been well described. The purpose of this investigation was to establish a dose-response curve for electrical stimulation regimens designed to improve quadriceps femoris muscle recovery in patients after anterior cruciate ligament reconstruction. SUBJECTS AND METHODS: We analyzed data from a subsample (n = 52) of patients receiving electrical stimulation (N = 110) who were involved in a large, multicenter randomized clinical trial investigating treatment strategies designed to enhance quadriceps femoris muscle recovery. Fifty-two subjects (40 male, 12 female), with an age range of 15 to 43 years (mean = 25, SD = 7), participated in 4 weeks of quadriceps femoris muscle training using either portable, battery-powered home stimulators or console stimulators designed for clinical use. Training intensities were monitored by logging the electrically elicited knee extension torque and expressing this torque as a percentage of the uninvolved quadriceps femoris muscles' maximal voluntary contraction force. After the 4 weeks of training, isometric muscle torque was assessed and a dose-response curve was generated. The relationship between training intensity and quadriceps femoris muscle torque was assessed with Pearson Product-Moment Correlation Coefficients. RESULTS: A significant, linear correlation was found between training intensity and quadriceps femoris muscle torque. Subjects training with console, clinical generators trained at higher intensities than those training with portable, battery-operated generators; such training resulted in higher quadriceps femoris muscle torque. CONCLUSION AND DISCUSSION: These results support the use of high-intensity electrical stimulation and do not support the use of low-intensity or battery-powered stimulators when the goal is recovery of quadriceps femoris muscle force production in the early phases of rehabilitation after anterior cruciate ligament surgery. [Snyder-Mackler L, Delitto A, Stralka SW, Bailey SL. Use of electrical stimulation to enhance recovery of quadriceps femoris muscle force production in patients following anterior cruciate ligament reconstruction.

Adolescent↗

PubMed1996

Electrical stimulation and biofeedback effect on recovery of tenodesis grasp: a controlled study.

OBJECTIVE: Evaluate the effectiveness of electrical stimulation and biofeedback on the recovery of tenodesis grasp in tetraplegic individuals during the initial phase of acute rehabilitation. DESIGN: A 2 x 2 block design was used with subjects randomized to treatment groups. Forty-five subjects completed the study. SETTING: Inpatient occupational therapy department. SUBJECTS: Inpatients with tetraplegia, first admission for rehabilitation after an acute spinal cord injury. INTERVENTIONS: The four treatment groups were: conventional treatment, electrical stimulation, biofeedback, and combined electrical stimulation and biofeedback. The treatment period was between 5 and 6 weeks. MAIN OUTCOME MEASURES: Manual muscle testing and scoring of activities of daily living performance by a blinded evaluator. RESULTS: All four treatment groups showed improvements. No treatment group was superior to the others. CONCLUSIONS: Biofeedback and electrical stimulation alone or in combination offer no advantages over conventional rehabilitation treatment of wrist extensors in tetraplegic patients after spinal cord injury.

Activities of Daily Living↗

PubMed2000

Electrical stimulation for faecal incontinence in adults.

BACKGROUND: Faecal incontinence is a particularly embarrassing and distressing condition with significant medical, social and economic implications. Electrical stimulation has been used with apparent success in the treatment of faecal incontinence. However, standards of treatment are still lacking and the magnitude of alleged benefits has yet to be established. OBJECTIVES: To determine the effects of electrical stimulation for the treatment of faecal incontinence in adults. SEARCH STRATEGY: We searched the Cochrane Incontinence Group trials register, the Cochrane Controlled Trials Register, Medline, Embase and reference lists of potentially eligible articles up to November 1999. Date of the most recent searches: November 1999. SELECTION CRITERIA: All randomised or quasi-randomised trials evaluating electrical stimulation in adults with faecal incontinence. DATA COLLECTION AND ANALYSIS: Three reviewers assessed the methodological quality of potentially eligible trials and two reviewers independently extracted data from the included trial. A wide range of outcome measures were considered. MAIN RESULTS: Only one eligible trial with 40 participants was identified. It was a randomised trial, but it suffered from methodological drawbacks and did not follow up patients beyond the end of the trial period. Findings from this trial suggest that electrical stimulation with anal biofeedback and exercises provides more short-term benefits than vaginal biofeedback and exercises for women with obstetric-related faecal incontinence. No further conclusions could be drawn from the data available. REVIEWER'S CONCLUSIONS: At present, there are insufficient data to allow reliable conclusions to be drawn on the effects of electrical stimulation in the management of faecal incontinence. There is a suggestion that electrical stimulation may have a therapeutic effect, but this is not certain. Larger, more generalisable trials are needed.

Adult↗

PubMed1979

Emotional responses to subcortical electrical stimulation in psychiatric patients.

Subcortical electrical stimulation was applied to the prospective surgical target area during 158 stereotactic operations in 135 psychiatric patients. The following target areas were studied: rostral cingulum below and in front of the genu of the corpus callosum (52 cases) genu (46) cingululum just above the genu (11) middle cingulum (6) anterior internal capsule (33) subcaudate region, 'substantia innominata' (10 cases). Forty-seven per cent of the cases reacted to stimulation with subjective emotional sensory responses. Stimulation of differ targets had significantly different results. Responses were obtained most frequently from the cingulum and genu, and least frequently from the anterior capsule and subcaudate regions. Stimulation of the rostral cingulum often caused 'negative' responses, i.e. an increase in or the appearance of anxiety and tension (11/15 cases). The opposite was true of the adjacent genu of the corpus callosum; on stimulation of this structure anxiety and tension disappeared or diminished (18/19 cases). Schizophrenic patients experienced such 'positive' responses significantly more often than non-schizophrenics. In non-anesthetized patients autonomic reactions were very rare.

Adolescent↗

PubMed1997

[Intraoperative extra strong electrical stimulation in the treatment of peripheral nerve injury].

In order to enhance the therapeutic effectiveness of peripheral nerve injury, intraoperative extrastrong electrical stimulation was used in peripheral nerve surgery. In 16 cases of incomplete peripheral rnerve injuries or poorly regeneratedn erves, continuous intraoperative electrophysiological monitoring was used for guidance of neurolysis. Meanwhile, extrastong electrical stimulation was applied. The latency and amplitude before and after electrical stimulation were recorded and the extent of improrement was compared. In all cases, the latency and amplitude were improved after neurolysis and electrical stimulation. Clinical follow-up also showed that the function of corresponding innorvated muscle was improved. Continuous intraoperative extrastrong electrical stimulation could be used as an practical measure to increase the effectiveness of peripheral nerve treatment.

Adolescent↗