Microcomputer program for automated action potential waveform analysis

A program for action potential waveform analysis based on a PC compatible computer is described. Single or averaged action potentials are analyzed by obtaining its first derivative and using criteria which allow automatic measurement of several action potential components, including: depolarization rate, repolarization rate, amplitude, duration, resting membrane potential and afterhyperpolarization amplitude and slope. Data can be imported from pClamp (Axon Instruments) and exported to other software such as Excel, Sigmaplot and MatLab for example.

BgK anemone toxin inhibits outward K(+) currents in snail neurons

We studied the effects of BgK toxin on outward K(+) currents in isolated neurons of the snail Helix aspersa, using the whole cell patch clamp technique. BgK partially and reversibly blocked K(+) currents in the 1 pM to 100 nM concentration range (n=53). The dose-response curve for BgK current inhibition had a maximum blocking effect at 100 nM. Our results indicate that BgK is a potent, apparently non-selective, K(+) channel blocker in molluscan neurons.

Identity in adolescent survivors of childhood cancer

OBJECTIVE

To investigate identify formation among adolescent survivors of childhood cancer. Family functioning, perceived emotional support from family and peers, life stress, and anxiety produced by the cancer experience also were examined as they influenced identity development.

METHOD

Participants were 52 adolescent survivors and their mothers recruited from a medical center and 42 healthy adolescent counterparts and their mothers recruited from the community.

RESULTS

A greater frequency of survivors than their healthy peers was found within the foreclosed identity status. Factors associated with the foreclosed identity status included the cancer diagnosis, symptoms of posttraumatic stress disorder (PTSD), and family functioning characterized by greater levels of conflict.

CONCLUSIONS

Data were interpreted to suggest that the foreclosed identity status may serve a protective function in assisting survivors to cope with the stressors of the cancer experience.

(AC)23 [Z-2] polymorphism of the aldose reductase gene and fast progression of retinopathy in Chilean type 2 diabetics

A recent case-control study suggests that the allele (AC)23 of a variable number tandem repeat (VNTR) associated to the aldose reductase (ALR2) gene could be related to early retinopathy in Type 2 diabetics. By means of a longitudinal-retrospective study, we aimed to seek for a relationship between the rate of progression of retinopathy and the (AC)23 allele of the VNTR associated to the ALR2 gene. A random sample was obtained of 27 Type 2 diabetics (aged 68.1 +/- 10.6 years, diabetes duration = 20.7 +/- 4.8 years, mean HbA1 = 10.6 +/- 1.6%). The mean HbA1 was the arithmetic average of 2.2 measurements per patient per year of total glycosilated hemoglobin (Gabbay method, normal range: 4.2-7.5%). Retinopathy was graded by an Ophthalmologist in a scale from zero to four score points. The genotype of the (AC), VNTR was determined by 32P-PCR plus sequenciation in a Perkin-Elmer laser device. The Mann-Whitney test and either chi2 or Fisher's exact test were used. A P < 0.05 was considered as statistically significant. The retinopathy progression rate (RPR, points x year(-1)) was calculated by dividing the increment of retinopathy score (delta Retinopathy Score, [points]), by the duration of the follow up [years]. The 12 diabetics having the (AC)23 allele had a mean RPR 8.9 times higher (0.40 +/- 0.61 points x year(-1)) than the 15 patients who had alleles other than (AC)23 (0.045 +/- 0.099 points x year(-1), P = 0.037). Both groups were similar with respect to: mean HbA1 (10.5 +/- 1.4 and 10.7 +/- 1.7%, P = 0.95), age at diagnosis (48.5 +/- 6.3 and 46.3 +/- 14.0 years, P = 0.81), diabetes' duration (21.3 +/- 4.7 and 20.2 +/- 4.9 years, P = 0.41) and serum creatinine (0.89 +/- 0.2 and 1.13 +/- 0.5 mg dl(-1), P = 0.35). We concluded that, in Type-2 diabetics having similar glycemic control, the (AC)23 allele of the VNTR associated to the ALR2 gene, is associated to a 8.9 times faster progression of retinopathy than in patients who have other alleles.

Calcium channels functional roles in the frog semicircular canal

Different types of voltage-operated calcium channels have been described in hair cells; however, no clear functional role has been assigned to them. As a first functional characterization of vestibular calcium channels, we studied the effect of several calcium channel agonists and antagonists on whole nerve firing rate in an isolated frog semicircular canal preparation. Resting activity was affected by all dihydropyridines tested and by omegaconotoxin GVIA, whereas only nimodipine was able to reduce the mechanically evoked activity. These results indicate that nimodipine-sensitive channels play a major role in afferent transmitter release, and omega-conotoxin GVIA sensitive channels regulate the afferent firing (possibly on the postsynaptic side) but with a less important role.

Molecular modeling of the complexes between Saccharomyces cerevisiae phosphoenolpyruvate carboxykinase and the ATP analogs pyridoxal 5'-diphosphoadenosine and pyridoxal 5'-triphosphoadenosine. Specific labeling of lysine 290

Molecular mechanics calculations have been employed to obtain models of the complexes between Saccharomyces cerevisiae phosphoenolpyruvate (PEP) kinase and the ATP analogs pyridoxal 5'-diphosphoadenosine (PLP-AMP) and pyridoxal 5'-triphosphoadenosine (PLP-ADP), using the crystalline coordinates of the ATP-pyruvate-Mn(2+)-Mg(2+) complex of Escherichia coli PEP carboxykinase [Tari et al. (1997), Nature Struct. Biol. 4, 990-994]. In these models, the preferred conformation of the pyridoxyl moiety of PLP-ADP and PLP-AMP was established through rotational barrier and simulated annealing procedures. Distances from the carbonyl-C of each analog to epsilon-N of active-site lysyl residues were calculated for the most stable enzyme-analog complex conformation, and it was found that the closest epsilon-N is that from Lys(290), thus predicting Schiff base formation between the corresponding carbonyl and amino groups. This prediction was experimentally verified through chemical modification of S. cerevisiae PEP carboxykinase with PLP-ADP and PLP-AMP. The results here described demonstrate the use of molecular modeling procedures when planning chemical modification of enzyme-active sites.

The role of acculturation in the substance abuse behavior of African-American and Latino adolescents: advances, issues, and recommendations

This article provides a review of the literature on the acculturation of Latino and African-American adolescents to traditional European-American cultural values, and the effect on their substance abusing behaviors. The review includes a critical analysis of studies that examine the effects of acculturation on the mental health and well-being of Latino adolescents. Recent findings documenting the association between acculturation and substance abuse among Latino adolescents are discussed. The article also examines the dearth of research on the role of acculturation in the substance-abusing behaviors of African-American adolescents. The authors assert that understanding the effects of acculturation on these behaviors could begin to explain why African-American adolescent substance abuse rates have been historically lower than those of European-American and Latino adolescents. Also included is an examination of research on the role of acculturation in treatment outcomes of Latino and African-American adolescents.

[Health status and functional limitations in the elderly population of the University Region of Health of Puerto Rico: methodologic aspects and prevalence estimates]

In order to plan the health services for the elderly population, it is necessary to quantify their health status and their functional capacity. In Puerto Rico, few epidemiological studies have been conducted regarding functional capacity and chronic diseases in the elderly population. One of the difficulties to undertake these studies is the high cost and risks to move this population for clinical exams, in addition to the methodology limitation of self-report in the elderly population. This study shows the use of logistic regression to estimate the prevalence of chronic diseases and functional capacity, when the observed data are not consisted with the planed sampling scheme. Four hundred and eighty-seven elderly persons (65 yr. and over) were interviewed in the municipalities of Canóvanas, Carolina, Loíza and Trujillo Alto in Puerto Rico, using a cross-sectional design. More than half of the elderly had visual problems (IC 95%: 54.8%, 63.8%), arthritis (IC 95%: 52.7%, 61.5%) and hypertension (IC 95%: 47.3%, 56.3%). In the case of hypertension, significant differences (p < 0.05) by sex were observed, where women reported a higher prevalence than men. One of the higher prevalences in the functional capacity status was with urine accidents. More than one-third of the population is estimated to have this problem (IC 95%: 34.7%, 43.4%). One-fourth of the population had limitations with going out for shopping (IC 95%: 23.9%, 31.9%) and using public and private transportation (IC 95%: 19.5%, 26.9%). We conclude that the applied methodology was consistent with the estimation presented in the literature and statistics from the Puerto Rico Health Department. However, it is necessary to continue assessing the design and analytical methodology, in order to undertake consistent and periodic evaluations of the elderly population.

[Aldose reductase gene polymorphism and rate of appearance of retinopathy in non insulin dependent diabetics]

BACKGROUND

Recent studies suggest that polymorphisms associated to the aldose reductase gene could be related to early retinopathy in noninsulin dependent diabetics (NIDDM). There is also new interest on the genetic modulation of coagulation factors in relation to this complication.

AIM

To look for a possible relationship between the rate of appearance of retinopathy and the genotype of (AC)n polymorphic marker associated to aldose reductase gene.

PATIENTS AND METHODS

A random sample of 27 NIDDM, aged 68.1 +/- 10.6 years, with a mean diabetes duration of 20.7 +/- 4.8 years and a mean glycosilated hemoglobin of 10.6 +/- 1.6%, was studied. The genotype of the (AC)n, polymorphic marker associated to the 5' end of the aldose reductase (ALR2) gene was determined by 32P-PCR plus sequenciation. Mutations of the factor XIII-A gene were studied by single stranded conformational polymorphism, sequenciation and restriction fragment length polymorphism.

RESULTS

Four patients lacked the (AC)24 and had a higher rate of appearance of retinopathy than patients with the (AC)24 allele (0.0167 and 0.0907 score points per year respectively, p = 0.047). Both groups had similar glycosilated hemoglobin (11.7 +/- 0.2 and 10.5 +/- 1.6% respectively). Factor XIII gene mutations were not related to the rate of appearance of retinopathy.

CONCLUSIONS

Our data suggest that the absence of the (AC)24 allele of the (AC)n polymorphic marker associated to the 5' end of the aldose reductase gene, is associated to a five fold reduction of retinopathy appearance rate.

Cytomegalovirus infection in patients with inflammatory bowel disease

OBJECTIVE

It has been suggested that, in inflammatory bowel disease, cytomegalovirus behaves in the intestine as a nonpathogenic bystander, and even its finding in intestinal mucosa has unclear clinical relevance. We report our experience with a small series of patients with refractory inflammatory bowel disease and cytomegalovirus infection and their clinical outcome.

METHODS AND RESULTS

Nine patients with moderate-severe attacks of inflammatory bowel disease did not respond to i.v. prednisone (1 mg/kg/day) for a mean of 24 days. Four of these patients were further treated with i.v. cyclosporine A (4 mg/kg/day). Cytomegalovirus infection was diagnosed in two patients after resection for treatment failure. In the remaining patients, cytomegalovirus infection was diagnosed in endoscopic mucosal biopsies and i.v. ganciclovir was then administered at a dose of 10 mg/kg/day for 2-3 wk. Five of these patients went into clinical remission, allowing corticosteroid and cyclosporine A discontinuation. Follow-up biopsies were performed and in all cases cytomegalovirus could not be detected in the colonic tissue. Two patients needed to be treated with intravenous cyclosporine A after antiviral therapy because of persistence of clinical symptoms despite the elimination of cytomegalovirus infection.

CONCLUSIONS

Cytomegalovirus infection may play a role in the natural history of refractory inflammatory bowel disease and in some of its complications. The clearance of cytomegalovirus in colonic mucosa may lead some of these patients to remission.

Cognitive and academic late effects among children previously treated for acute lymphocytic leukemia receiving chemotherapy as CNS prophylaxis

OBJECTIVE

Examine cognitive and academic late effects among children and adolescents who had received central nervous system (CNS) prophylactic chemotherapy alone for acute lymphocytic leukemia (ALL); none had received whole brain radiation therapy (RT).

METHOD

Subjects included 47 children and adolescents from 5 to 22 years of age who were treated on the same protocol and had been off treatment from 2 to 7 years at the time of assessment.

RESULTS

As a group the survivors displayed generally average performance on measures of cognitive and academic abilities, although they differed from normative means on tests of nonverbal skills. Girls performed more poorly than the normative sample on nonverbal tasks, while no differences were found for boys. Age at diagnosis and time off treatment were not significantly associated with cognitive and academic functioning for survivors of this particular chemotherapy-only protocol.

CONCLUSIONS

Data were interpreted to support generally modest potential late effects in specific areas for children and adolescents surviving ALL. These findings suggest a need for monitoring nonverbal cognitive skills for childhood survivors of ALL, particularly for girls.

Giving birth: Guatemalan women's voices

OBJECTIVE

To gain an understanding of the cultural meanings of giving birth for Guatemalan women.

DESIGN

Ethnographic, focusing on the birth stories of Guatemalan women and their perceptions of the sociocultural context of childbearing.

PARTICIPANTS AND SETTING

Thirty Guatemalan women (15 primiparae and 15 multiparae) of mixed Mayan and Ladino heritage who had given birth to healthy full-term infants were interviewed during the early postpartum weeks. These women lived in small villages in the Sacatepéquez District of Guatemala. These audiotaped interviews were conducted in the Nacional Pedro de Bethancourt Hospital, in clinics, in the homes of the women, or in central plazas.

RESULTS

The sociocultural context of giving birth in Guatemala is described, including common beliefs about pregnancy and childbirth and the meaning and significance of having children. The predominant themes found were the sacred nature of childbirth; the need for reliance on God during pregnancy, childbirth, and childrearing; and the bittersweet paradox of giving birth.

CONCLUSION

With increasing numbers of Central American refugees and immigrants of childbearing age entering the United States, it is important for nurses to recognize, acknowledge, and respect specific cultural practices related to childbearing.

Effective adjuvant chemotherapy for advanced nasopharyngeal carcinoma in children: a final update of a long-term prospective study in a single institution

PURPOSE

The purpose of this study was to determine the efficacy and toxicity of a doxorubicin/cyclophosphamide-based chemotherapy and local radiation therapy in children with locally advanced or metastatic nasopharyngeal carcinoma (NPC).

PATIENTS AND METHODS

Twelve patients aged 6 to 20 years old were treated with a chemotherapy regimen comprised of vincristine (1.5 mg/m2) and doxorubicin (45 mg/m2) on day 1 and cyclophosphamide (210 mg/m2) and 5-fluorouracil (240 mg/m2) on days 1 to 5. Chemotherapy was administered every 3 weeks for 1 to 2 years. Radiotherapy to the primary site (59 to 68 Gy) and to the neck (59 to 66 Gy) was given before or after 2 to 4 courses of chemotherapy.

RESULTS

All patients achieved a complete response 4 to 16 months from the start of therapy (median 7 months). Nine patients have remained tumor free from 2 to 21 years (median 11 years) from diagnosis. One child was lost to follow-up and one died of tuberculosis; both were disease-free. One child developed a secondary osteosarcoma in the left mandible. Chemotherapy caused grade 4 neutropenia and thrombocytopenia in four patients. There were no therapy-related deaths and the most common late effect of therapy was neck fibrosis, which was observed in all patients. We conclude that the chemotherapy and radiotherapy regimen used in this study is highly effective for children and adolescents with locally advanced NPC and is associated with tolerable toxicity.

Occurrence and Partial Characterization of a New Mechanically Transmissible Virus in Mashua from the Ecuadorian Highlands

Mashua (Tropaeolum tuberosum) is a tuber crop indigenous to the Andean highlands and of economic value to its native people as a food and medicinal crop. Field plants often exhibit symptoms typical of virus infection, including interveinal chlorosis, leaf cupping, distortion, and stunting. Using an herbaceous host range, at least 1 mechanically transmissible virus was detected in each of 10 accessions. All virus isolates tested reacted to potyvirus group antiserum in indirect enzyme-linked immunosorbent assays (ELISA). Results of monoclonal antibody testing using antigen coated plate (ACP) ELISA, where virions are disrupted to expose cryptotopes, indicated that isolate Tt 4 has epitopes in common with maize dwarf mosaic potyvirus A (MDMV-A). Polyclonal antiserum produced to purified preparations of the Tt 4 isolate reacted in indirect ELISA to Tt 4, the common strain of potato potyvirus Y (PVY-C), less strongly to tobacco etch potyvirus (TEV) and potato potyvirus A (PVA), but not to 11 other potyviruses, including MDMV-A. Conversely, the Tt 4 isolate reacted strongly in indirect ELISA to antisera to bean common mosaic potyvirus (BCMV) and watermelon mosaic potyvirus 2 (WMV-2), but not antisera to 12 other potyviruses. Our data suggest that isolate Tt 4 is a distinct potyvirus closely related to and sharing external epitopes with PVY-C, TEV, PVA, WMV-2, and BCMV, and buried epitopes with MDMV-A. The virus has been tentatively named Tropaeolum mosaic potyvirus (TropMV). A survey of T. tuberosum in Ecuador revealed that TropMV was widespread, being detected by ACP-ELISA in 34 of 46 accessions at the National Institute for Agricultural Research's Santa Catalina Research Station, Quito, and all eight production fields surveyed.

[Epidemiology of the osteoporotic fracture of the hip in the province of Palencia]

BACKGROUND

Hip fracture is the most severe consequence of osteoporosis. The aim of the present study was to know the incidence of osteoporotic hip fracture in the Palencia province, its direct economical consequences and characteristics associated with the origin episode.

PATIENTS AND METHODS

All patients aged over 49 years who had a nontraumatic hip fracture during the second semester of 1994 and the first semester of 1995 were included in the study. An analysis of costs was performed and each patient received a questionnaire to know the circumstances associated with the episode.

RESULTS

During the study period the overall incidence of hip fracture was 83/100,000 inhabitants/year, which corresponds to an adjusted incidence of 240.9/100,000 inhabitants older than 49 years (336.8 women and 120.7 men). There was an exponential growth, with peak values starting at 80 years. The female/male ratio was 2.8 and the mean age 80.8 years. Twenty-four percent of fractures occurred in institutionalized persons, with an adjusted incidence of 1,107/100,000 inhabitants/year, which corresponds to a relative risk of 13.57 (95% CI: 10.06-18.28). No significant differences were observed between trochanteric and neck fractures. Ninety-seven percent of fractures occurred after a fall, usually in the morning or afternoon (86%), with lateral direction and impact on the greater trochanter (89%). The mortality rate during admission was 5.9%. The mean cost of care during admission was 1,170,000 pesetas.

CONCLUSIONS

The incidence of hip fracture in Palencia is slightly higher than the national mean, probably due to populational ageing. The risk of fracture reaches alarming proportions in the institutionalized population. The implementation of efficient preventive measures, particularly among the exposed populations, is necessary.

A microcomputer program for automated neuronal spike detection and analysis

A system for on-line spike detection and analysis based on an IBM PC/AT compatible computer, written in TURBO PASCAL 6.0 and using commercially available analog-to-digital hardware is described here. Spikes are detected by an adaptive threshold which varies as a function of signal mean and its variability. Since the threshold value is determined automatically by the signal-to-noise ratio analysis, the user is not actively involved in controlling its level. This program has been reliably used for the detection and analysis of the spike discharge of vestibular system afferent neurons. It generates the interval-joint distribution graph, the interval histogram, the autocorrelation function, the autocorrelation histogram, and phase-space graphs, thus, providing a complete set of graphical and statistical data for the characterization of the dynamics of neuronal spike activity. Data can be exported to other software such as Excel, Sigmaplot and MatLab, for example.

Transcriptional control of a nuclear gene encoding a mitochondrial fatty acid oxidation enzyme in transgenic mice: role for nuclear receptors in cardiac and brown adipose expression

Expression of the gene encoding medium-chain acyl coenzyme A dehydrogenase (MCAD), a nuclearly encoded mitochondrial fatty acid beta-oxidation enzyme, is regulated in parallel with fatty acid oxidation rates among tissues and during development. We have shown previously that the human MCAD gene promoter contains a pleiotropic element (nuclear receptor response element [NRRE-1]) that confers transcriptional activation or repression by members of the nuclear receptor superfamily. Mice transgenic for human MCAD gene promoter fragments fused to a chloramphenicol acetyltransferase gene reporter were produced and characterized to evaluate the role of NRRE-1 and other promoter elements in the transcriptional control of the MCAD gene in vivo. Expression of the full-length MCAD promoter-chloramphenicol acetyltransferase transgene (MCADCAT.371) paralleled the known tissue-specific differences in mitochondrial beta-oxidation rates and MCAD expression. MCADCAT.371 transcripts were abundant in heart tissue and brown adipose tissue, tissues with high-level MCAD expression. During perinatal cardiac developmental stages, expression of the MCADCAT.371 transgene paralleled mouse MCAD mRNA levels. In contrast, expression of a mutant MCADCAT transgene, which lacked NRRE-1 (MCADCATdeltaNRRE-1), was not enriched in heart or brown adipose tissue and did not exhibit appropriate postnatal induction in the developing heart. Transient-transfection studies with MCAD promoter-luciferase constructs containing normal or mutant NRRE-1 sequences demonstrated that the nuclear receptor binding sequences within NRRE-1 are necessary for high-level transcriptional activity in primary rat cardiocytes. Electrophoretic mobility shift assays demonstrated that NRRE-1 was bound by several cardiac and brown adipose nuclear proteins and that these interactions required the NRRE-1 receptor binding hexamer sequences. Antibody supershift studies identified the orphan nuclear receptor COUP-TF as one of the endogenous cardiac proteins which bound NRRE-1. These results dictate an important role for nuclear receptors in the transcriptional control of a nuclear gene encoding a mitochondrial fatty acid oxidation enzyme and identify a gene regulatory pathway involved in cardiac energy metabolism.

Antagonism of glutamate receptors by a chromatographic fraction from the exudate of the sea anemone Phyllactis flosculifera

In the search for new glutamate antagonists it seems promising to characterize the effects of venom from invertebrates that prey mainly on crustaceans. In this work, the exudate of the sea anemone Phyllactis flosculifera was used as a source of this type of compound. The action of chromatographic fraction D from P. flosculifera was tested upon microion-tophoretically evoked glutamate responses in intracellular recordings from central neurons of the land snail Zachrysia guanensis. Bath application of fraction D (2-8 mg/ml, n = 13) diminished both the excitatory and the inhibitory components of glutamate agonists in Z. guanensis neurons; this action was dose-dependent and partially reversible. Fraction D actions were also tested in the multiunit spontaneous and mechanically evoked responses of the glutamatergic junction between hair cells and afferent neurons of the axolotl Ambystoma tigrinum. Pressure ejection of fraction D in concentrations ranging from 0.5 to 2 mg/ml (n = 9) decreased the spontaneous and mechanically evoked activity of semicircular canal afferent neurons and the responses evoked by kainic acid and alpha-amino-3-hydroxy-5-methylisoxasole-4-propionic acid. This action was also dose-dependent and partially reversible. These results indicate that fraction D acts as a glutamate receptor antagonist in snail and amphibian neurons. Further studies are required to characterize the active compounds responsible for this action and its specificity upon the subtypes of glutamate receptors.

Histochemistry and role of nitric oxide synthase in the amphibian (Ambystoma tigrinum) inner ear

Nicotinamide adenine dinucleotide phosphate reduced-diaphorase (NADPH-d) histochemistry was investigated in the axolotl (Ambystoma tigrinum) inner ear. Hair cells showed an intense NADPH-d reaction; afferent neurones also stained but less intensely than hair cells. Effects of NG-nitro-L-arginine (L-NOARG) on the basal discharge and mechanical responses of semicircular canal afferent neurones recorded extracellularly were also studied. L-NOARG (1 mu M) diminished the basal discharge and the response of afferent neurones to sinusoidal mechanical stimuli to 45 +/- 6.4% and 65 +/- 5.3% (mean +/- SEM) of control value, respectively. These findings suggest that production of nitric oxide (NO) by hair cells and probably also by afferent neurones contributes to the basal discharge and the response of afferent neurones to mechanical stimuli.

[Creutzfeldt-Jakob disease. Clinical, electrophysiological and histopathological correlations]

Creutzfeldt-Jakob disease (CJD) is one of a small group of the so-called spongiform encephalopathies. It is a rare transmissible disorder which is characterized by progressive and irreversible neurological damage. There are few reports where clinical manifestations are correlated with neurophysiologic and histopathologic findings. The present paper includes three cases of CJD where alterations in evoked potentials and brain mapping studies gave valuable information, especially in those where the clinical picture and the electroencephalogram were non-specific, we conclude that these alterations suggest that the classic histopathological changes in C-J disease involves both cortical and subcortical structures.

NMDA-mediated potentiation of the afferent synapse in the inner ear

In an isolated vestibular organ preparation from the axolotl (Ambystoma tigrinum), glycine (10-0.01 microM) perfusion had no effect in the resting control condition, but significantly modified the response of afferent fibres to mechanical stimuli, producing a slowly increasing discharge rate during sinusoidal mechanical stimulation periods. This action was dependent upon the stimulus duration and was antagonized by 7-chloro-kynurenic acid (7-ClKyn), 2-amino-5-phosphonopentanoic acid (AP5), N-allyl-nor-metazocina (MK-801) and extracellular magnesium. These results indicate that glycine modulates the afferent synapse in the vestibular organ, and that, NMDA receptors codify long lasting mechanical stimuli.