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PubMedDate not supplied

Intracavernosal pressure monitoring in mice: responses to electrical stimulation of the cavernous nerve and to intracavernosal drug administration.

With the development of transgenic mice to evaluate mechanisms of erectile function, it appears particularly advantageous to develop a standardized mouse model of penile erection. The purpose of the study reported here was to evaluate the novel application of intracavernosal pressure (ICP) monitoring in the mouse during electrophysiologic and pharmacologic induction of penile erection. In anesthetized adult male mice, the cavernous nerves (CN) were isolated unilaterally, and the corpora cavernosa were exposed. A 24-gauge angiocath (intravenous catheter) was inserted into the right corpus cavernosum to monitor the ICP, and a 30.5-gauge needle was inserted into the left corpus cavernosum for intracavernosal drug administration. ICP was recorded during CN-stimulated or pharmacostimulated erections. Electrical stimulation of the CN significantly increased the ICP (from 10.09 +/- 2.01 to 34.62 +/- 2.71 mm Hg, P < .05), which then returned to baseline pressure after termination of the electrical stimulation. Pretreatment with intracavernosal administration of the nitric oxide synthase inhibitor, nitro-L-arginine methyl ester (0.1 mg), inhibited the electrical stimulation-induced changes in ICP (7.17 +/- 1.46 vs 10.38 +/- 2.17 mm Hg, not significant [NS]). Also, intracavernosal administration of papaverine (0.4 mg) produced a significant increase in ICP (from 8.51 +/- 0.69 to 26.37 +/- 5.7 mm Hg, P < .05). We concluded that this technique might be applied to perform quantitative erection physiologic experiments with the mouse as an economical and experimentally advantageous animal model, particularly with the development of transgenic mice to evaluate mechanisms of erectile function.

Animals↗

PubMed1995

[Histological changes, muscle force and fatigability after electrical stimulation to experimentally paralyzed muscles].

In order to use functional electrical stimulation effectively in paralyzed muscle treatment, changes in the maximal muscle force, muscle fatigue, and histological changes were evaluated in electrically stimulated muscles. Study 1. Tissue damage by percutaneous intramuscular electrodes implanted into the quadriceps muscle was examined in rat. Stimulation was conducted at various output voltages, and for various durations of time, in order to assess the histological changes in the muscle around the electrodes. Study 2. Electrodes were implanted into the bilateral quadriceps and gastrocnemius muscles of adult cat, and the unilateral muscles were then stimulated from 3 weeks following the transection of the spinal cord at the T9 level. Stimulus parameters were divided into two groups; as "A" stimulation: at -8V for 15min twice/week, and as "B" stimulation: at -16V for 30 min 4 times/week. The histological changes were examined using the myofibrillar ATPase method to determine the diameters and occupation ratios for each muscle fiber type. RESULTS. Study 1. Significant tissue damage began to occur when the voltage output created the maximum muscle contraction force. Until that critical voltage point was reached, tissue damage was not significant, regardless of the duration of the stimulation. Study 2. The maximum muscle force decreased until 4 weeks after the transection, then increased regardless of the presence of electrical stimulation. The muscle fatigability of the non-stimulated muscle was greater than that of the stimulated muscle. High voltage, long duration, and frequent stimulation was effective in controlling fatigue. The ratio of type I fibers was higher in the stimulated muscle. There was no evidence, however, of suppressing muscle fiber atrophy after electrical stimulation. These results suggested that electrically stimulating paralyzed muscles was effective for suppressing muscle fatigue, and for reducing the ratio of type I fibers. In clinical use, the output voltage should be kept below the voltage that induces the maximum muscle contraction to prevent tissue damage.

Animals↗

PubMed2000

Electrical stimulation: a societal perspective.

Societal perspective on functional electrical stimulation is colored by media influence, popular thought, and political climate as much as by the science that supports it. The purpose of this article is to examine how these influences facilitate or inhibit the application of electrical stimulation in today's world and to describe the challenges facing the use of electrical stimulation in the future. Emphasis will be placed on perceived need, cost, and available resources and how these factors must be addressed to utilize functional electrical stimulation successfully in society.

Attitude to Health↗

PubMed1977

Schedule control of behavior reinforced by electrical stimulation of the brain.

Electrical stimulation of the brain was used to train rats to respond on random interval schedules. Stimulation was either delayed for 0.5 second and preceded by a brief signal, delayed and unsignaled, or presented contiguously with the response. In every case, responding was maintained on schedules and showed resistance to extinction typical of food-reinforced responding. Priming was never necessary. These data cast doubt on the generality of beliefs about the behavioral effects of brain stimulation reinforcement.

Animals↗

PubMed1996

Modulation of neglect hemianesthesia by transcutaneous electrical stimulation.

The effects of transcutaneous electrical stimulation on deficits of tactile perception contralateral to a hemispheric lesion were investigated in 10 right brain-damaged patients and in four left brain-damaged patients. The somatosensory deficit recovered, transiently and in part, after stimulation of the side of the neck contralateral to the side of the lesion, in all 10 patients with lesions in the right hemisphere, both with (six cases) and without (four cases) left visuo-spatial hemineglect, and in one left brain-damaged patient with right hemineglect. In three left brain-damaged patients without hemineglect, the treatment had no detectable effects. In one right brain-damaged patient, the stimulation of the side of the neck ipsilateral to the side of the lesion temporarily worsened the somatosensory deficit. These effects of transcutaneous electrical stimulation are similar to those of vestibular stimulation. The suggestion is made that these treatments modulate, through afferent sensory pathways, higher-order spatial representations of the body, which are pathologically distorted toward the side of the lesion. The modulatory effect is direction-specific: the defective internal representation of the contralesional side may be either partly restored, improving the disorder of tactile perception, or further impoverished, worsening the deficit. The possible neural basis of this modulation is discussed.

Adult↗

PubMed1990

[Studies of experimental scoliosis produced by electrical stimulation. With special reference to the histochemical properties of the muscle].

1) Back muscles on the right side of the rat were daily stimulated with electrical pulses through implanted electrodes. As a result, a scoliosis with convexity toward the non-stimulated side was produced. The cobb angle increased with time and became 18.6 +/- 9.9 degrees on average after 3 weeks. 2) On the stimulated side, type I fibers showed a significant increase in diameter. The area they occupied in the cross section, as well as the ratio of the area against that of type II fibers, were increased. These increases disappeared 3 weeks after the termination of the stimulation, whereas the scoliosis remained almost the same, maintaining an average angle of 17.2 +/- 7.4 degrees after 3 weeks. 3) From these results, the possibility was suggested that electrical stimulation is of use in treating idiopathic scoliosis.

Animals↗

PubMed1991

Effect of electric stimulation on vestibular compensation in guinea pigs.

The effect of electric stimulation on vestibular compensation was studied in guinea pigs. Pharmacological labyrinthectomy was performed by injecting chloroform into the right middle ear under light ether anesthesia. The guinea pigs were divided into four groups: a control group which was not electrically stimulated after labyrinthectomy, a group stimulated with 0.6 mA square wave, a group stimulated with 0.3 mA square wave, and a group stimulated with 0.6 mA pulse wave. Electric stimulation, which started 1 h and 15 min after labyrinthectomy, was given through retroauricular electrodes. Nystagmus and head deviations were recorded and analyzed to assess the process of compensation at 1, 2, 3, 4, 5, 8, 12, 18 and 24 h after labyrinthectomy. Electrically stimulated groups, especially group 0.6 mA square wave and group 0.6 mA pulse wave, showed faster compensation in nystagmus and head-body deviation than the control group. Therefore, in this study, electric stimulation seemed to contribute favorably to vestibular compensation.

Animals↗

PubMed1978

Acute electrical stimulation for urinary incontinence.

Acute or maximal electric stimulation of the pelvic floor muscles has been used in incontinent patients who are suitable candidates for electrical stimulation, but unwilling or unable to use the anal plug electrodes. Seventeen of 20 patients had relief or improvement of their incontinence. However 5 of these 17 patients had a relapse of symptoms on follow-up, requiring a repeat treatment with acute or maximal electrical stimulation.

Electric Stimulation Therapy↗

PubMed1991

Electrical stimulation of the thigh muscles after reconstruction of the anterior cruciate ligament. Effects of electrically elicited contraction of the quadriceps femoris and hamstring muscles on gait and on strength of the thigh muscles.

The effects of neuromuscular electrical stimulation on the strength of the thigh muscles and on gait were examined in ten patients after reconstruction of the anterior cruciate ligament. The patients were randomly assigned to one of two treatment groups: neuromuscular electrical stimulation and volitional exercise, or volitional exercise alone. A four-week course of electrically elicited co-contraction of the thigh muscles resulted in significant attenuation of the characteristic loss of strength of the quadriceps as compared with volitional exercise. There was no significant difference between groups in any measure of performance of the hamstring muscles. In the group that received neuromuscular electrical stimulation, the values for cadence, walking velocity, stance time of the involved limb, and flexion-excursion of the knee during stance were significantly different from those of the volitional exercise group. Flexion-excursion of the knee during stance was directly and significantly correlated with strength of the quadriceps femoris muscle. Flexion of the knee during stance was qualitatively different in the involved extremity as compared with the uninvolved extremity in all patients. There is a rapid flexion of the knee at weight acceptance that is maintained throughout stance and probably reflects stabilization of the joint by muscular coactivation to compensate for weakness of the quadriceps. The patients who received neuromuscular electrical stimulation had stronger quadriceps muscles and more normal gait patterns than those in the volitional exercise group.

Adolescent↗

PubMed1999

Electrical stimulation has no adverse effect on pregnant rats and fetuses.

PURPOSE: Electrical stimulation has been considered a contraindication in pregnant women with various voiding dysfunctions, because of the potential to cause teratogenicity or abortion. However, it is not known whether electrical stimulation can cause fetal malformation or abortion. The purpose of this study is to evaluate whether electrical stimulation has any adverse effect on pregnant rats and fetuses. MATERIALS AND METHODS: Twenty Sprague-Dawley pregnant rats were divided into two groups: electrical stimulation group (n = 10) and sham controls (n = 10). Rats in the stimulation group were stimulated 7 hours every day from Day 4 to Day 20 of gestation. All pregnant rats were sacrificed and fetuses were examined at near term (Day 20 of gestation). The number of fetuses, resorptions, fetal liability, body weight and gross appearance were recorded. Viscera and skeleton stained with Alizarin Red S were examined under stereoscope. RESULTS: All pregnant rats were healthy during the gestation period and no abortions were noted. Fetal body weight in the stimulation group (2.27 +/- 0.51 gm.) was not significantly different from sham group (2.13 +/- 0.51 gm.; p = 0.91). No significant difference was found in the number of resorptions between both groups. All fetuses were alive at the time of cesarean section. No fetal malformation was observed in gross appearance, viscera and skeleton of all rats. CONCLUSIONS: Electrical stimulation did not have any adverse effect on pregnant rats and their fetuses. Termination of pregnancy is not advised for prospective mothers when electrical stimulation has been performed inadvertently in early pregnancy.

Animals↗

PubMed1987

The effect of isometric short-term electrical stimulation on denervated muscle.

Electrical stimulation was applied daily for 20 minutes to denervated rabbit extensor digitorum longus muscle. One group was stimulated with short tetani, another with 1-Hz frequency, using isometric contractions for both. Tetanic stimulation induced severe fibrosis and is harmful to denervated muscle. One Hertz stimulation retarded denervation-induced fatigue and atrophy, as well as slowing of contraction time.

Animals↗

PubMed2002

Transcutaneous electrical stimulation of an auricular acupuncture point decreases anesthetic requirement.

BACKGROUND: German anesthesiologists have long used transcutaneous electrical stimulation of an acupuncture point near the tragus to reduce anesthetic requirement in unblinded and uncontrolled trials. This is known as auricular electrically stimulated analgesia. The authors therefore tested the hypothesis that auricular electrically stimulated analgesia reduces anesthetic requirement. METHODS: In a randomized, double-blind, crossover trial, volunteers were anesthetized twice with desflurane. Electrical stimulation of an auricular acupuncture point in the vicinity of the tragus was used on 1 randomly assigned day, and no electrical stimulation of the same point was used on the other study day. Treatment consisted of bilateral electrical stimulation of the lateralization control point, 3 cm anterior to the tragus. The 10-mA current was set to 299 Hz on the dominant side of the face and to 149 Hz on the contralateral side. Anesthetic requirement was determined by the Dixon up-and-down method and was defined by the average desflurane concentration required to prevent purposeful movement of the extremities in response to noxious electrical stimulation. RESULTS: Ten men and 10 women completed the protocol. Electrical stimulation of the lateralization control point reduced anesthetic requirement by 11 +/- 7% (P < 0.001), with the reduction being similar in women and men. Women required more desflurane to prevent movement on the control day than the men (5.5 +/- 1.0 vs. 4.6 +/- 0.6 vol%; P = 0.028). CONCLUSION: This double-blinded trial with an objective outcome demonstrates that electrical stimulation of the lateralization control point significantly reduces anesthetic requirement.

Acupuncture Points↗

PubMed1987

Evaluation of gait with multichannel electrical stimulation.

Short, intensive multichannel electrical stimulation therapy was evaluated in 14 hemiplegics after stroke or head injury. The stimulation of the peroneal nerve, soleus, quadriceps, hamstring, gluteus maximus, and triceps brachii muscles with individually preprogrammed sequences was applied by surface electrodes at the beginning of gait rehabilitation. The patients started walking with the support of a therapist, gradually increased the walking distance and all reached independent ambulation with a crutch after an average of 14 stimulation sessions. A portable microprocessor six-channel stimulator/stride analyzer enabled the collection of gait parameters and recording of statistical mean values of stride time, gait symmetry, right and left stance times, and their standard deviations. Without additional equipment, several hundred stimulated strides were measured during each stimulation session.

Adolescent↗

PubMed2006

Cortical localization of external urethral sphincter activation by transcranial electrical stimulation.

PURPOSE: Repetitive transcranial electrical stimulation (rTES) was used to activate descending output to the external urethral sphincter muscle. METHODS: Motor evoked potentials (MEPs) were recorded from external urethral sphincter (EUS), and anterior tibial (TA) muscles following high voltage rTES in 9 consecutive patients undergoing spine surgery. Anesthesia was achieved by continuous propofol/narcotic infusion without paralytic agents. Anodal cortical stimulation was delivered at C4/C3, C2/C1, and Cz/Fz locations in each patient. Latency and amplitude of the MEP was measured and compared for each bipolar stimulation montage. RESULTS: The mean latency was 20.24 +/- 1.3 msec. for Cz/Fz; 20.19 +/- 1.1 msec. for C4/C3 and 20.19 +/- 1.1 msec. for C2/C1. Statistical analysis showed no significant difference in latency between the three sites (F(2,15) = 0.004; p > 0.05). The mean amplitude was 37.14 +/- 24.3 microV for Cz/Fz; 113.33 +/- 100.6 microV for C4/C3; and 85 +/- 73.9 microV for C2/C1. A significant difference between the amplitudes at three sites was observed (F(2,8) = 5.2; p < 0.05). The amplitude at C4/C3 was significantly greater than amplitude at CzlFz (t (8) = 3.08; p < 0.05), but data did not give enough evidence to believe that difference between amplitudes for site C4/C3 & C2/C1 was significant (p > 0.05). CONCLUSIONS: This study shows that the intraoperative MEP monitoring of the EUS is a feasible method. Furthermore, activation of descending axonal outflow to the EUS muscle is best achieved by cortical stimulation directed from C4 to C3 or C2 to C1 points.

Adolescent↗

PubMedDate not supplied

Activity elicited in the auditory pathway of the rat by electrical stimulation of the cochlea.

The activity elicited by electrical stimulation of the cochlea in the auditory pathway was assessed in an animal model of cochlear implants on the basis of the induction of the immediate early gene c-fos and single neuron recordings. Electrical stimulation of the cochlea induced Fos-like immunoreactivity in the cochlear nucleus, mainly in its dorsal nucleus, in the superior olivary complex, in the lateral lemniscus, but not in the central nucleus of the inferior colliculus, the main relay nucleus in the auditory midbrain. However, single unit recordings from the inferior colliculus, ipsilateral and contralateral to the electrically stimulated cochlea, showed clear responses of single neurons, reminiscent of those elicited by acoustic stimulation. These findings provide immunocytochemical and electrophysiological evidence that the various nuclei of the auditory pathway are activated by electrical stimulation of the cochlea.

Animals↗

PubMed2003

Electrical stimulation of thalamic Nucleus Submedius inhibits responses of spinal dorsal horn neurons to colorectal distension in the rat.

In 78 halothane-anesthetized rats, we characterized the responses of single neurons in the dorsal horn of L(6)-S(1) spinal segments to a noxious visceral stimulus (colorectal balloon distension, CRD), and studied the effects of focal electrical stimulation of Nucleus Submedius (Sm) on these responses using standard extracellular microelectrode recording techniques. A total of 102 neurons were isolated on the basis of spontaneous activity. Eighty (78%) responded to CRD, of which 70% had excitatory and 30% had inhibitory responses. Neurons showed graded responses to graded CRD pressures (20-100 mmHg), with maximum excitation or inhibition occurring at 100 mmHg. Responses to noxious (pinch, heat) and innocuous (brush, tap) cutaneous stimuli were studied in 73 of the spinal dorsal horn neurons isolated. Fifty-seven (78%) of these neurons (46 CRD-responsive and 11 CRD-nonresponsive) had cutaneous receptive fields, of which 35 (61%) were small and ipsilateral, 14 (25%) were large and ipsilateral, 7 (12%) were large or small and bilateral, and 1 (2%) was small and contralateral. Sixty-one percent of these neurons responded to both noxious and innocuous cutaneous stimulation, 35% responded only to noxious stimulation, and 4% responded only to innocuous stimulation. Electrical stimulation (50-300 microA) of the contralateral Sm produced intensity-dependent attenuation of the CRD-evoked activities of most neurons (18/28 of CRD-excited and 7/12 of CRD-inhibited) tested. Sm stimulation produced facilitation of CRD responses of only one neuron (CRD-inhibited). Sm stimulation had no effects on spontaneous activity. These data indicate that Sm may be involved in the descending inhibitory modulation of visceral nociception at the spinal level.

Animals↗

PubMed1984

Analgesia produced by electrical stimulation of the brain.

Electrical stimulation of the brain can produce a selective and potent modulation of responding to noxious stimuli in animals and man. The influence of various stimulation parameters is discussed. Brain stimulation at numerous loci results in analgesia. The most well characterized regions are the mesencephalic periaqueductal gray matter and the medullary raphe nuclei. One pain inhibitory system activated by brain stimulation involves a neural circuit from the PAG to the medullary raphe nuclei. Output from there descends via the DLF to modulate pain transmission in the dorsal horn of the spinal cord. Other analgesia systems are also activated by brain stimulation. Compelling evidence implicates endogenous opiates in SPA. Monoaminergic neurotransmitters are also involved in SPA. Brain stimulation has proven to be useful for the management of some forms of intractable pain in man.

Analgesia↗

PubMed1999

Effect of the duration of electrical stimulation on the analgesic response in patients with low back pain.

BACKGROUND: Electrical stimulation of peripheral nerves produces acute analgesic effects. This randomized, sham-controlled, crossover study was designed to evaluate the effect of differing durations of electrical stimulation on the analgesic response to percutaneous electrical nerve stimulation in 75 consenting patients with low back pain. METHODS: All patients received electrical stimulation for four different time intervals (0, 15, 30, and 45 min) in a random sequence over the course of an 11-week study period. All active percutaneous electrical nerve stimulation treatments were administered using alternating frequencies of 15 and 30 Hz three times per week for 2 consecutive weeks. The prestudy assessments included the health status survey short form questionnaire and 10-cm visual analog scale scores for pain, physical activity, and quality of sleep, with 0 being the best and 10 being the worst. The pain scoring was repeated 5-10 min after each 60-min study session and 24 h after the last treatment session with each of the four methods. The daily oral analgesic requirements were assessed during each of the four treatment blocks. At the end of each 2-week treatment block, the questionnaire was repeated. RESULTS: Electrical stimulation using percutaneously placed needles produced short-term improvements in the visual analog scale pain, physical activity, and quality of sleep scores, and a reduction in the oral analgesic requirements. The 30-min and 45-min durations of electrical stimulation produced similar hypoalgesic effects (48+/-21% and 46+/-19%, respectively) and were significantly more effective than either 15 min (21+/-17%) or 0 min (10+/-11%). The 30- and 45-min treatments were also more effective in improving physical activity and sleep scores over the course of the 2-week treatment period. In contrast to the sham treatment (0 min), the health status survey short form revealed that electrical stimulation for 15 to 45 min three times per week for 2 weeks improved patient function. CONCLUSION: The recommended duration of electrical stimulation with percutaneous electrical nerve stimulation therapy is 30 min.

Adult↗