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PubMed2002

Acupuncture stimulation inhibits somato-renal sympathetic A- and C-reflexes in anesthetized rats.

Stimulation of peripheral nerve afferent for example tibial nerve by a strong electrical stimulation (rectanfular wave with 20V amplitude; pulse duration of 0.5 ms, 0.3 pulses/sec) can evoke a discharge of the somato-sympathetic reflex which is recorded on the efferent of renal sympathetic nerve. The component of the somato-sympathetic reflex can be divided into two parts: one is related to the transmission of the myelinated afferent fibers with a short lantency (41+/-2 ms) and is defined A-reflex, the other is related to the transmission of the unmyelinated afferent fibers with a long latency (210+/-13 ms) and is defined C-reflex. In the present study, an acupuncture needle (diameter 0.34 mm) was inserted into the hind limbs of the rat, dorsolaterally at the area of acupoint: huantiao (GB30), at a depth of 4-5 mm and was twisted right and left twice every second during recording the somato-renal sympathetic reflex. It was found that acupuncture on the huantiao acupoint significantly inhibited both A- and C-reflexes. There was no different inhibition of the A- and C-reflexes by acupuncture on the right or left side. However acupuncture on the fore limbs of the rat dorsolaterally at the area of acupoint: quchi (LI11) showed no effect on neither A- nor C-reflexes. These results suggest that acupuncture at the same spinal segment of the acupoint inhibits the somatorenal sympathetic reflex.

Acupuncture↗
PubMed1976

[Clinicophysiological studies of orbicularis oculi reflex in brain stem diseases].

Orbicularis oculi reflex is consisted of two components; one is early reflex response (R1) which is 14.1 +/- 2.2 msec in latency, and the other is late reflex response (R2) that is 35.0 +/- 8.6 msec in latency (mean +/- 2SD). R1 is observed on the ipsilateral side of stimulation and R2 is visible bilaterally on ipsiand contralateral sides of stimulation. Clinically orbicularis oculi reflex can be recorded easily, however, its clinical and physiological significance has not been clearly solved. Orbicularis oculi reflex was tested on patients with the brain stem lesions of various kinds, and the factors influencing to the reflex pathways were examined, such as the site and the type of lesions, sleep, several anesthetics and the level of consciousness. Results obtained were as follows; 1) both R1 and R2 disappeared or prolonged in latencies by nuclear as well as peripheral facial nerve palsy, since the facial nerve was the final common pathway. 2) on cases of facial sensory disturbance R1 prolonged in latency with concomitant delay of R2 response. 3) both R1 and were attenuated as soon as the alpha rhythmicity of the EEG was disappeared. Administration of thiamylal also attenuated both the R1 and R2, however, ketamine (a dissociative anesthetic) enhanced the R1 in amplitude and suppressed R2. These findings indicated that the R1 and R2 were in some extent regulated from brain stem reticular formation and the orbicularis oculi reflex should be an useful diagnostic measure to detect imparied consciousness. 4) also the reflex should be used to know the extent of neoplastic process in the cerebellar hemisphere to the brain stem. 5) recovery curve of R1 from double shock stimuli (conditioned and test) indicated that this reflex was different from H wave of the spinal cord because of absent refractory period and shorter facilitatory period ranging between 40 to 60 msec.

Adolescent↗
PubMed2000

Reflex lacrimation in patients with glaucoma and healthy control subjects by fluorophotometry.

PURPOSE: Steady state tear turnover (TTO), defined as TTO under normal physiological conditions, is significantly lower in patients with untreated glaucoma than in healthy control subjects. To obtain more information on the effect of glaucoma on lacrimation, a method for quantification of reflex lacrimation was developed and applied to patients with glaucoma or ocular hypertension and healthy control subjects. METHODS: After instillation of 2 microl of fluorescein (2%), the decay of fluorescein concentration in tears was measured by fluorophotometry over 10 minutes to determine steady state TTO. Then, reflex lacrimation was induced by stimulating the trigeminal nerve with ethanol vapor via the nostrils. Thereafter, the decay of fluorescein and corresponding steady state TTO were determined again. An index of reflex lacrimation, defined as the percentage decrease in fluorescein concentration as a result of stimulation, was calculated by forward and backward extrapolation of the steady state decay of the fluorescein concentration in tears, relative to the time of stimulation. RESULTS: The index of reflex lacrimation was determined in 16 patients with newly discovered but not yet treated glaucoma, 16 patients with untreated ocular hypertension, and 16 healthy control subjects. The values did not differ between groups (mean +/- SD, 67.0%+/-17.7%, 63.5%+/-21.3%, and 70.4%+/-19.6%, respectively; ANOVA, P>0.25). Surprisingly, the steady state TTO after stimulation was lower than that before stimulation in each group (ratio, 0.62+/-0.46; paired t-test, P<0.04). CONCLUSIONS: The method developed is appropriate for the quantification of reflex lacrimation. Reflex lacrimation is not influenced significantly by glaucoma or ocular hypertension. The decreased steady state TTO after reflex stimulation may be caused by exhaustion of the lacrimal glands after excessive reflex lacrimation, indicating that normal lacrimation probably also contains reflex tears.

Adult↗
PubMedDate not supplied

The trigemino-cervical reflex in normal subjects.

There are only few reports on the trigemino-cervical reflex in humans and there is debate over the best method of reflex examination. The aim of this study was, comparing different methods, to provide a reproducible method for evaluating the trigemino-cervical reflex. The trigemino-cervical reflex was studied in 32 healthy volunteers. The stimulation was applied to the supraorbital, infraorbital or mental nerve. Recordings were performed bilaterally from the sternocleidomastoid and trapezius muscles at rest. The reflex was also examined during maximal voluntary contraction of the sternocleidomastoid muscle after supraorbital nerve stimulation. It presented as a two-component reflex if recorded from a tonically active muscle and as a one-component reflex if recorded from a relaxed muscle. The most reproducible reflex responses were obtained from the resting sternocleidomastoid muscle after stimulation of the supraorbital nerve. In conclusion, the trigemino-cervical reflex may be most easily obtained from the relaxed sternocleidomastoid muscle after supraorbital nerve stimulation.

Adult↗
PubMedDate not supplied

Assessment of motoneuron excitability using recurrent inhibition and paired reflex depression protocols: a test of reliability.

Motor output may be regulated by both pre- and post-synaptic mechanisms. The purpose of this study was to investigate the reliability of two measurement protocols, which purport to examine spinal mechanisms responsible for gating motoneuron excitability. Nine subjects (aged 29 +/- 5 years) were tested using two soleus H-reflex protocols; 1) recurrent inhibition (RI) and 2) paired reflex depression (PRD). The dependent variable for each protocol was the peak-to-peak amplitude of the conditioned Hoffmann reflex (H-reflex). Seven trials were obtained for each subject under each condition as well as control values to assess test-retest reliability. After all trials were collected the subjects rested for at least five minutes after which the process was repeated. Each subject returned to the lab after a period of no less than 24 hours at which time the process was repeated. Protocol #1: Control reflexes (20% of maximal motor response) were obtained during quiet stance. After obtaining control trials two reflex responses were elicited which were separated by 10 ms on each trial to assess recurrent inhibition (Pierrot-Deseilligny et al., 1976; Bussel and Pierrot-Deseilligny, 1977). Protocol #2: Again a double-pulse technique was used to assess reflex activation history on motoneuron pool output (Trimble et al., 2000). This protocol utilized two reflex stimuli of the same intensity separated by 80 ms. The peak-to-peak amplitude of the control, RI conditioned and PRD conditioned H-reflexes exhibited intraclass reliability estimates of .97, .97 and .93 respectively. To achieve a reliability of rI > or = .80, it is recommended that a minimum of 2 trials be used for the RI protocol and that 4 trials be used for the PRD protocol. The results indicate that both techniques provide a means to objectively and reliably measure spinal mechanisms for gating motoneuron pool output.

Adult↗
PubMed2002

[The effects of intrathecally administered baclofen on somato-sympathetic reflex potentials].

We investigated the antinociceptive effect of intrathecally administered S(-)-baclofen and R (+)-baclofen in cats using somato-sympathetic reflex potentials derived from lumbar sympathetic ganglion by stimulation of the femoral nerve. S(-)-baclofen 10 mg maximally reduced both A reflex potential and C reflex potential to 65.3% and 83.7% of control values, respectively, 1 minute after the administration, but these changes were not significant. The inhibition of A reflex potential at this dosage was greater than that of blood pressure and heart rate induced by the same dosage of S(-)-baclofen. While, R(+)-baclofen 1 mg maximally inhibited A reflex potential to 48.6% of control value 20 minutes after the administration, and this change was significant (P < 0.05). The inhibition of A reflex potential was greater than that of blood pressure and heart rate induced by the same dosage of R(+)-baclofen. This dosage of baclofen reduced C reflex potential to 66.4% of control value 10 minutes after the administration. The degree of reduction of A and C reflex potentials induced by 1 mg of R(+)-baclofen was higher in comparison with that induced by 10 mg of S(-)-baclofen. These reduction of A and C reflex potentials were reversed by 1 to 1.5 mg of intrathecally administered saclofen. These results indicate that R(+)-baclofen has higher potency than S(-)-baclofen and suggest that S(-)-baclofen and R(+)-baclofen show antinociceptive effect by intrathecal administration. On the other hand, it is possible that these two drugs exert antinociceptive effect via A delta fiber.

Analgesics↗
PubMed1975

The expiration reflex during ontogenesis in the rat.

The authors studied the elicitability of the expiration and aspiration reflex and of the respiratory reaction from the tracheobronchial area in 131 anaesthetized rats (aged 1-15 days, adult and biologically old). They found that the expiration reflex could be elicited, in the rat, from the first day of life, at a time when other respiratory reflexes were not yet stable. In young rats, the expiration reflex was often followed by a cough reaction which was absent in adult animals. The findings indicate that the expiration reflex is one of the most important respiratory reflexes of the early postnatal period in the rat, because the aspiration reflex and the respiratory reaction from the bronchi were not stable until the 15th day of life. In biological old rats, the expiration reflex is less frequently elicited and its intensity attains about half the value found in adult animals. The aspiration reflex and the respiratory reaction from the bronchi are likewise less readily elicited than in adult animals, but when the intensity of their maximum expiratory effort is increased, it is far greater.

Age Factors↗
PubMed2003

Activity of the laryngeal abductor and adductor muscles during cough, expiration and aspiration reflexes in cats.

We studied the temporal relationships and the patterns of electromyographic activities of the posterior cricoarytenoid and thyreoarytenoid muscles (laryngeal abductor and adductor), the diaphragm and abdominal muscles in anesthetized cats during mechanically induced tracheobronchial and laryngopharyngeal coughs, expiration and aspiration reflexes. The posterior cricoarytenoid muscle activity reached the maxima just before the peak of diaphragmatic activity in both types of cough and aspiration reflexes and slightly before the top of abdominal muscle activity in coughs and the expiration reflex. Thus, this muscle contributes to the inspiratory phase of coughs and aspiration reflex and also to the expulsive phase of coughs and the expiration reflex. The thyreoarytenoid muscle presented strong discharges in the compressive phase of coughs and expiration reflex (during the rising part of the abdominal muscle activity) and in the subsequent laryngoconstriction (following the diaphragmal and/or abdominal muscle activity) in all four reflexes. This muscle was also slightly activated at the beginning of the aspiration reflex. The existence of four phases of the cough reflex is also discussed.

Abdominal Muscles↗
PubMed1992

[Correlation between electrically-induced stapedius reflex and discomfort threshold in cochlear implant patients].

Electrically elicited stapedius reflex thresholds are an objective criteria for the fitting of speech processors in very young children. Reflex thresholds generally fit well within the upper third of a subject's individual dynamic range, the difference between electrical threshold of hearing, (T) and maximum comfort (C) levels and can be used to predict ultimate behavioral maximum comfort levels. In acoustically elicited stapedius reflexes a saturation of impedance amplitude can be registered at approximately 110 dB, which is 90% of the dynamic range. Assuming a similar relationship for the electrically elicited stapedius reflex there would be two values within the dynamic range which could be used for extrapolation of the threshold level. In the present study, the electrically elicited stapedius reflex was examined in 16 deaf patients who had received 22-channel Clark/NUCLEUS cochlear implants. Using an apical, a medial and a basal electrode pair, different stimulation positions within the cochlea were tested. The contralateral reflexes could be elicited in 11 patients (69%). A saturation of the reflex amplitude was recordable in 10 subjects, at least in one of the electrode pairs. The reflex saturation in all cases was located close to the uncomfortable loudness level within the subjects' dynamic ranges (at 95% dynamic). This finding is comparable to acoustic matter. As a result, these data together with reflex threshold data suggest a means for predicting to predict the threshold levels.

Acoustic Impedance Tests↗
PubMedDate not supplied

[Factors that affect the Hoffmann reflex as a tool used in neurophysiological examination].

INTRODUCTION: The Hoffmann reflex, or H-reflex, which is the electrical equivalent of the myotatic reflex, is a very valuable tool for evaluating the reflex pathway and for investigating the mechanisms that regulate the intensity of its response. Yet, the complex interaction of the H-reflex circuit with other neural components requires a tight-fit recording protocol. DEVELOPMENT: In this paper we present a review of the main technical, physiological and methodological factors that affect the recording of the H-reflex when used as an instrument for neurophysiological exploration. The paper reviews aspects concerning the method of stimulation, recording and analysing the reflex response. The physiological mechanisms that interact to modulate the amplitude of the H-reflex, such as pre-synaptic inhibition, post-activation depression and the excitability of the motoneurons, are described and the different methods used to control the variations that arise in each case are also outlined. Lastly, a summary of the main points to be borne in mind when recording the H-reflex is presented. CONCLUSIONS: Due to the large number of variables and the non-linear way they interact with one another, we must proceed with care when drawing conclusions from the discussion of the results obtained under such strict protocols. Progress also has to be made in the development and application of new mathematical, statistical and modelling tools in order to achieve a more accurate interpretation of the findings that are observed.

Electromyography↗
PubMed1991

A cellular analysis of inhibition in the siphon withdrawal reflex of Aplysia.

Recent behavioral experiments examining the siphon withdrawal reflex of Aplysia have revealed inhibitory effects of strong tail shock, a stimulus commonly used as an unconditioned stimulus in studies of associative and nonassociative learning in Aplysia. We utilized a reduced preparation to perform a cellular analysis of tail shock-induced inhibition in the siphon withdrawal reflex. First, we carried out behavioral studies that showed that the reduced preparation exhibits a siphon withdrawal reflex to water jet stimuli, and that tail shock produces inhibitory behavioral effects comparable to those in the intact animal: (1) strong shock produces transient inhibition of nonhabituated responses, and (2) a habituated response is facilitated by weak shock, but not by strong shock, suggesting that increasing tail shock intensity recruits the inhibitory process that competes with facilitation of habituated reflexes. Next, we carried out cellular studies that showed that the amplitude of the complex EPSP in siphon motor neurons elicited by water jet stimuli to the siphon also exhibits the inhibitory patterns produced by tail shock: (1) the nondecremented complex EPSP (a neural correlate of a nonhabituated siphon withdrawal reflex) is significantly inhibited 90 sec after strong tail shock and recovers to preshock levels 10 min later, and (2) the decremented complex EPSP (a neural correlate of a habituated reflex) is significantly facilitated by weak shock, but is not facilitated by strong shock. In addition to the complex EPSP, we simultaneously examined the monosynaptic connection between siphon sensory neurons and siphon motor neurons. The monosynaptic EPSP does not show the pattern of inhibitory modulation by tail shock exhibited by the siphon withdrawal reflex and the complex EPSP: (1) the nondecremented monosynaptic EPSP is not inhibited 90 sec after strong shock, but tends to be above preshock levels; and (2) the decremented monosynaptic EPSP is facilitated by weak as well as strong tail shock. Our results suggest that an important component of the inhibitory process triggered by strong tail shock is mediated by neural elements presynaptic to the siphon motor neurons. Because modulation of the monosynaptic connection between identified siphon sensory and siphon motor neurons does not parallel the tail shock-induced inhibitory patterns observed in the siphon withdrawal reflex and in the complex EPSP, other synaptic connections are likely to play an important role in mediating tail shock-induced inhibition in the siphon withdrawal reflex.

Animals↗
PubMedDate not supplied

The clinical grouping of skin reflexes in different forms of cerebral palsy.

Previous studies in healthy infants and children showed the gradual disappearance of skin reflexes at specific times: distal skin reflexes disappeared early while trunk-dorsal reflexes disappeared later. In this study the same twenty-eight skin reflexes on the extremities and the trunk were examined in one hundred and thirty-three cerebral palsy patients aged from 1.3 to 18 years. Some of these reflexes persisted longer and were more intense than in healthy children. In spastic forms of cerebral palsy they were mainly the distal skin reflexes that persisted longer, while in the dyskinetic form longer persistence of trunk-dorsal reflexes and stronger abdominal reflexes were found. In the cerebellar form only very low persistence of distal reflexes was ascertained.

Adolescent↗
PubMedDate not supplied

Diagnostic assessment of central and peripheral lesions by means of audiomotor reflex.

Audiomotor reflex is defined as an exteroceptive reflex evoked by a strong sound impulse, occurring on skeletal muscles, where it can be electromyographically registered. It is visually best noted on the facial and eyelid muscles. The physiological basis is the reflex arch consisted of receptor-cohlea, the afferent part, the primary reflex audiotory centre, the efferent part and the muscle-effector. The main physiological characteristic of the audiomotor reflex (AMR) in all healthy people is the symmetry of contractions of the same muscles on the left and the right side of the body. This symmetry occurs because of the crossed afferent connections. The symmetry of contraction was examined on the m.orbicularis oculi and also m.tibialis anterior utq. and it was found that the differences in the contraction of the pair of muscles (the same muscles on the left and on the right side of the body) are minimal and negligible. This fact makes us possible to propose the analysis of symmetry of the AMR contractions, measured on the same muscles on the left and right side of the body, as a diagnostic method for estimating the central and peripheral disorders. In order to evaluate the AMR method for the purpose, two investigations were conducted. The first investigation was conducted for the purpose of evaluating the diagnostic value of the AMR method at patients with central disorders. Eight hemiparetic children and nine healthy children were examined by means of routine stimulation (110 dB, 1 kHZ, 100 ms). The monitoring of the reflex contraction was on the m.tibialis anterior utq. It was evident that all parameters of the AMR m.tibialis anterior (amplitude, latency and duration of reflex contraction) in hemiparetic children were changed on the affected hemiparetic side, in terms of increased excitability of motoneurons. In order to evaluate the AMR method in peripheral disorders, i.e. paresis of the n.facialis, the examining of patients with paresis of n.facialis of varied duration was carried out. The results showed very clearly the prolongation of the reflex latency at the damaged side of face, and also a decrease of the amplitude of varied degrees. Conclusively, it can be said that the investigations confirmed the value of the AMR method (i.e. the analysis of the AMR contraction symmetry) as a valid and objective neurophysiological method for examining pathologic changes in the area of the AMR reflex arch and in parts of the central nervous system.

Adolescent↗
PubMed1987

Respiration and airway reflexes after transversal brain stem lesions in cats.

The effect of brain stem transection at different levels of the pons Varolii and the medulla oblongata on respiration and on cough and the aspiration and expiration reflex elicited by mechanical stimulation of the relevant parts of the respiratory tract was studied in experiments on 13 anaesthetized, unparalyzed cats. The results of 142 respiratory reflex elicitation tests showed that: 1. Compared with the control state, transection of the upper and middle part of the pons Varolii and transection at the level of the pontomedullary junction reduced the respiration rate (p less than 0.001), increased the duration of inspiration and expiration (p less than 0.001, transection 10 mm rostrally to the obex) and gave rise to apneustic breathing (8 mm), or to tonic, respiration-modulated activity of the phrenic nerve and diaphragm (6 mm). 2. Successive transection of the pons and the pontomedullary junction region led chiefly to a drop in maximum expiratory pleural pressure values (p less than 0.01-0.001) during cough and the expiration reflex and to a drop in maximum inspiratory pleural pressure values during the aspiration reflex (p less than 0.02-0.001). 3. Transection of the upper part of the medulla oblongata always led to permanent arrest of rhythmic respiration, during which cough and the expiration reflex could not be elicited while the aspiration reflex persisted (though in a weakened form). This state was followed by gasping, during which only a highly elicitable aspiration reflex persisted. 4. It can be assumed from the above findings that the central mechanisms responsible for the development of powerful expiratory efforts in cough and the expiration reflex could be localized in the pons Varolii, while those integrating the aspiration reflex are probably localized mainly in the medulla oblongata.

Animals↗
PubMed1995

Sacroiliac joint manipulation decreases the H-reflex.

Joint manipulation is widely utilized clinically to decrease pain and increase the range of motion of joints displaying limited mobility. Evidence of efficacy is based on subjective reports of symptom improvement as well as on the results of clinical trials. Experiments were designed to determine whether or not sacroiliac joint manipulation affects the amplitude of the Hoffman (H) reflex. Surface EMG recordings of the reflex response to electrical stimulation of the tibial nerve in the popliteal fossa were made from the soleus muscle. The averaged amplitudes of H-reflexes were compared on both legs before and after either sacroiliac joint manipulation or a sham procedure. H-reflex amplitude was significantly decreased (12.9%) in the ipsilateral leg (p < 0.001) following a sacroiliac joint manipulation while there was no significant alteration following the sham intervention. There was no significant alteration in reflex excitability in the contralateral leg to the sacroiliac joint manipulation. To further investigate the mechanism of these reflex alterations, the local anaesthetic cream EMLA (Astra Pharmaceuticals) was applied to the skin overlying the sacroiliac joint and the experiments were repeated on a different group of subjects. This was intended to determine if excitation of cutaneous afferents was responsible for the reflex excitability changes. There was still a significant decrease in reflex excitability (10.6%) following sacroiliac joint manipulation (p < 0.001). These findings indicate that joint manipulation exerts physiological effects on the central nervous system, probably at the segmental level. The fact that the changes persisted in the presence of cutaneous anaesthesia suggests that the reflex changes are likely to be mediated by joint and/or muscle afferents.

Adolescent↗
PubMed1994

[Effects of ketamine on somatosympathetic reflex discharges in cats].

Effects of ketamine on somatosympathetic reflex discharges induced from sympathetic trunk with electrical stimulation of superficial peroneal nerve were investigated in 51 cats under anesthesia with urethane and alpha chloralose. These reflex discharges through spinal cord and medulla oblongata consist of two components, A and C reflexes, which are derived from somatic myelinated and unmyelinated afferent fiber respectively. Amplitudes of both A and C reflex potentials were depressed significantly after intravenous injection of ketamine 10 mg.kg-1. The maximum depression was observed 5 min after administration. In decerebrated cats with surgical transection at the midbrain, both A and C reflexes were also depressed after administration of the same dosages, and the maximum level of the depression was more profound than that in brain intact cats. After intrathecal injection of ketamine 1 mg.kg-1 to the lumbar spinal region, a slight depression of C reflex was found, but, dosages of 10 mg.kg-1 significantly depressed both A and C reflexes to the similar levels as those in iv injection to brain intact cats. The maximum depression was observed 30 min after administration. The depressive effects on both reflexes of intravenous ketamine 10 mg.kg-1 were not antagonized by naloxone 0.06 mg.kg-1 in brain intact cats. These results suggest that the suppressive effects of ketamine on somatosympathetic reflexes are caused by direct inhibition of medulla oblongata and spinal cord, whereas supra-midbrain regions may be activated by ketamine, and the effect of ketamine is predominant on medulla oblongata in this situation rather than on the spinal cord.

Action Potentials↗
PubMed1994

[A study of pathogenesis and symptoms of Tourette's syndrome--mainly on the importance of "startle reflex" through Latah reaction].

There is no established theory on pathogenesis of Tourette's syndrome, but recently, a theory of the British school of behaviorism; 'transient tics' and the more serious case, Tourette's syndrome which ensues on the fixation of the startle reflex, have received attention. So we determined, whether pathogenesis and symptoms of Tourette's syndrome could be systematically explained by "the startle reflex theory". Authors assumed that the startle reflex was composed of two divided actions, a series of muscular movements which started with eye blinks and terminated in the flexion of lower limbs (the primary startle reflex system), and more purposeful and complicated actions which occasionally arose from these movements (the secondary startle reflex system). On the basis of this supposition, we considered simple tics which are usually called "tics", those are the manifestation of astonishment by the primary startle reflex system, and complex tics; echo phenomena, coprolalia, complex movements, and so on, which are said to be pathognomonic of Tourette's syndrome, are the expression of amazement by the secondary startle reflex system. Furthermore, we formulated a hypothesis that in the latter case, the secondary startle reflex system contains the senses of orientation and defense, and the defense mechanism which is innately imprinted in common throughout human race, and covered through individual development, is released and fixed in the form of complex movements or echo phenomena in an emergency, such as astonishment. To discuss further, we determined Latah reaction minutely (especially in "Imu" of the Ainu race in Japan) in which intricate symptoms had been suggested as one of the senses of defense, were closely related to Tourette's syndrome. For more concrete study, we presented two severe cases of Tourette's syndrome. Considering the circumstances mentioned above, pathogenesis and symptoms of Tourette's syndrome could be explained by the startle reflex theory. Finally, we analyzed several psychiatrical syndromes which were provoked by astonishment, we concluded that it was necessary to emphasize Tourette's syndrome was only a part of those more comprehensive syndromes which could be called "startle syndromes".

Adult↗
PubMed1993

Effect of the beta-carboline abecarnil on spinal reflexes in mice and on muscle tone in genetically spastic rats: a comparison with diazepam.

Abecarnil is a beta-carboline agonist at benzodiazepine receptors with potent anxiolytic activity but no muscle relaxant side effects in rodents. Clinical experience suggests that changes in the muscle tone induced by benzodiazepines are related to their effects on spinal reflexes. The authors therefore analyzed the effect of treatment with abecarnil on spinal monosynaptic (Hoffmann reflexes) and polysynaptic (flexor) reflexes in mice and the influence of abecarnil on muscle tone in genetically spastic rats. The i.v. administration of abecarnil in mice (dose range, 0.02-1 mg/kg) depressed flexor reflexes in a dose-dependent manner; Hoffmann reflexes remained unchanged. Administration of diazepam i.v. (0.01-1 mg/kg) also reduced flexor reflexes and had little or no effect on Hoffmann reflexes. In genetically spastic rats, i.v. administration of abecarnil (10-30 mg/kg) decreased the muscle tone in a dose- and time-dependent manner. A similar muscle relaxant effect was observed in such rats after i.v. administration of diazepam (0.1-0.8 mg/kg). By contrast, i.p. administration of abecarnil in mice did not influence spinal reflexes up to the dose of 1 mg/kg and, in genetically spastic rats, did not affect muscle tone up to the dose of 100 mg/kg. Administration of diazepam i.p. (1 mg/kg) depressed flexor reflexes in mice and over the range 0.2 to 5 mg/kg produced a dose- and time-dependent decrease of muscle tone in genetically spastic rats. The muscle relaxant effect of i.p. diazepam could be antagonized by i.p. administered abecarnil. These studies thus demonstrate that i.v. but not i.p. administration of abecarnil may result in muscle relaxant action in mice and in genetically spastic rats.

Animals↗