Outdoor pollen is a trigger of child and adolescent asthma emergency department presentations: A systematic review and meta-analysis.

BACKGROUND: In the context of increased asthma exacerbations associated with climatic changes such as thunderstorm asthma, interest in establishing the link between pollen exposure and asthma hospital admissions has intensified. Here, we systematically reviewed and performed a meta-analysis of studies on pollen and emergency department (ED) attendance. METHODS: A search for studies with appropriate search strategy in MEDLINE, EMBASE, Web of Science and CINAHL was conducted. Each study was assessed for quality and risk of bias. The available evidence was summarized both qualitatively and meta-analysed using random-effects models when moderate heterogeneity was observed. RESULTS: Fourteen studies were included. The pollen taxa investigated differed between studies, allowing meta-analysis only of the effect of grass pollen. A statistically significant increase in the percentage change in the mean number of asthma ED presentations (MPC) (pooled results from 3 studies) was observed for an increase in 10 grass pollen grains per cubic metre of exposure 1.88% (95% CI = 0.94%, 2.82%). Time series studies showed positive correlations between pollen concentrations and ED presentations. Age-stratified studies found strongest associations in children aged 5-17 years old. CONCLUSION: Exposure to ambient grass pollen is an important trigger for childhood asthma exacerbations requiring ED attendance. As pollen exposure is increasingly a problem especially in relation to thunderstorm asthma, studies with uniform measures of pollen and similar analytical methods are necessary to fully understand its impact on human health.

Residential greenness and allergic respiratory diseases in children and adolescents - A systematic review and meta-analysis.

BACKGROUND: The aetiology of allergic respiratory disease in children is not yet fully understood. Environmental factors are believed to play a major part. The amount of green vegetation surrounding the home (residential greenness) has been recently identified as a potentially important exposure OBJECTIVES: Our goal was to provide a systematic review and quantitative summary of the evidence regarding the relationship between residential greenness and allergic respiratory diseases in children. METHODS: Peer-reviewed literature published prior to 1 March 2017 was systematically searched using nine electronic databases. Meta-analyses were conducted if at least three studies published risk estimates for the same outcome and exposure measures. RESULTS: We included 11 articles across broad outcomes of asthma and allergic rhinitis. Reported effects were inconsistent with varying measures to define residential greenness. Only limited meta-analysis could be conducted, with the pooled odds ratios for asthma (OR 1.01 95%CI 0.93, 1.09; I2 68.1%) and allergic rhinitis (OR 0.99 95%CI 0.87, 1.12; I2 72.9%) being significantly heterogeneous. CONCLUSIONS: Inconsistencies between the studies were too large to accurately assess the association between residential greenness and allergic respiratory disease. A standardised global measure of greenness which accounts for seasonal variation at a specific relevant buffer size is needed to create a more cohesive body of evidence and for future examination of the effect of residential greenness on allergic respiratory diseases.

Breastfeeding and childhood acute otitis media: a systematic review and meta-analysis.

AIM: To synthesise the evidence on the association between duration and exclusivity of breastfeeding and the risk of acute otitis media (AOM). METHODS: Systematic review and meta-analysis following searching of PubMed, CINAHL and EMBASE electronic databases. RESULTS: Twenty-four studies, all from the USA or Europe, met the inclusion criteria. In the pooled analyses, any form of breastfeeding was found to be protective for AOM in the first 2 years of life. Exclusive breastfeeding for the first 6 months was associated with the greatest protection (OR 0.57 95% CI 0.44, 0.75), followed by 'more vs less' breastfeeding (OR 0.67; 0.59, 0.76) and 'ever vs never' breastfeeding (OR 0.67; 0.56, 0.80). CONCLUSION: This systematic review and meta-analysis provides evidence that breastfeeding protects against AOM until 2 years of age, but protection is greater for exclusive breastfeeding and breastfeeding of longer duration. Exclusive breastfeeding during the first 6 months was associated with around a 43% reduction in ever having AOM in the first 2 years of life. After 2 years of age, there is no evidence that breastfeeding protects against AOM; however, there were few studies and the evidence quality was low.

Breastfeeding and asthma and allergies: a systematic review and meta-analysis.

AIM: To systematically review the association between breastfeeding and childhood allergic disease. METHODS: Predetermined inclusion/exclusion criteria identified 89 articles from PubMed, CINAHL and EMBASE databases. Meta-analyses performed for categories of breastfeeding and allergic outcomes. Meta-regression explored heterogeneity. RESULTS: More vs. less breastfeeding (duration) was associated with reduced risk of asthma for children (5-18 years), particularly in medium-/low-income countries and with reduced risk of allergic rhinitis ≤5 years, but this estimate had high heterogeneity and low quality. Exclusive breastfeeding for 3-4 months was associated with reduced risk of eczema ≤2 years (estimate principally from cross-sectional studies of low methodological quality). No association found between breastfeeding and food allergy (estimate had high heterogeneity and low quality). Meta-regression found differences between study outcomes may be attributable to length of breastfeeding recall, study design, country income and date of study inception. Some of the protective effect of breastfeeding for asthma may be related to recall bias in studies of lesser methodological quality. CONCLUSION: There is some evidence that breastfeeding is protective for asthma (5-18 years). There is weaker evidence for a protective effect for eczema ≤2 years and allergic rhinitis ≤5 years of age, with greater protection for asthma and eczema in low-income countries.

Breastfeeding and the risk of dental caries: a systematic review and meta-analysis.

AIM: To synthesise the current evidence for the associations between breastfeeding and dental caries, with respect to specific windows of early childhood caries risk. METHODS: Systematic review, meta-analyses and narrative synthesis following searches of PubMed, CINAHL and EMBASE databases. RESULTS: Sixty-three papers included. Children exposed to longer versus shorter duration of breastfeeding up to age 12 months (more versus less breastfeeding), had a reduced risk of caries (OR 0.50; 95%CI 0.25, 0.99, I(2) 86.8%). Children breastfed >12 months had an increased risk of caries when compared with children breastfed <12 months (seven studies (OR 1.99; 1.35, 2.95, I(2) 69.3%). Amongst children breastfed >12 months, those fed nocturnally or more frequently had a further increased caries risk (five studies, OR 7.14; 3.14, 16.23, I(2) 77.1%). There was a lack of studies on children aged >12 months simultaneously assessing caries risk in breastfed, bottle-fed and children not bottle or breastfed, alongside specific breastfeeding practices, consuming sweet drinks and foods, and oral hygiene practices limiting our ability to tease out the risks attributable to each. CONCLUSION: Breastfeeding in infancy may protect against dental caries. Further research needed to understand the increased risk of caries in children breastfed after 12 months.

Reporting dental trauma and its inclusion in an injury surveillance system in Victoria, Australia.

BACKGROUND: This study investigated the frequency, patterns and causes of dental trauma in patients seeking emergency treatment at a dental hospital, and evaluated the impact of an electronic structured injury history form to collect key information. METHODS: A retrospective audit was undertaken of all emergency presentations at the Royal Dental Hospital of Melbourne from 2009 to 2012. Dental trauma and injury surveillance data were collected and evaluated with reference to the criteria of the Victorian Emergency Minimum Dataset. Statistical analysis included chi-squared and Fisher's exact tests. RESULTS: A total of 88,610 new emergency courses of care were created, with 3642 (4.1%) identified as new dental trauma cases in 3574 patients. A total of 6001 teeth were injured with a mean of 1.7 teeth per patient (range: 1-8 teeth). The improvement of injury surveillance information collected using the electronic form compared with the paper form was statistically significant (p<0.001). CONCLUSIONS: The dental trauma findings of this study are consistent with other studies regarding age, gender, location, cause and injury type. This study also confirmed the benefits of electronic collection of dental injury surveillance data that can assist policy planners and health service providers in designing and delivering effective dental injury prevention and management services.

Pattern and factors associated with utilization of dental services among older adults in rural Victoria.

BACKGROUND: In Australia, rural and regional areas have an increased proportion of older people who are ageing more rapidly than their metropolitan counterparts. This increase in the ageing population and its uneven geographic distribution is likely to pose an oral health challenge in the near future. METHODS: A cross-sectional study conducted in a sample of 226 community-dwelling adults aged 55 years and older, living in the City of Greater Bendigo who completed a questionnaire and received an oral examination. RESULTS: Overall, 51.2% of participants reported having been to the dentist in the previous 12 months. Reported barriers to dental care were: cost of services (32.7%), fear of dentists (25.8%), length of waiting lists (18.1%) and availability of oral health care services (11.1%). Living alone, gender, low income, lack of education, low self-perceived oral health needs, self-perceived barriers, edentulism, and presence of mobility problems were statistically significant variables associated with less use of dental services (p < 0.0001). CONCLUSIONS: Access to dental care is affected by financial and structural barriers as well as other predisposing and enabling factors among older adults. Thus, increase in user services will require efforts to reduce financial barriers and make dental care culturally and linguistically competent.

The role of seasonal grass pollen on childhood asthma emergency department presentations.

BACKGROUND: Few studies have focused on the role of grass pollen on asthma emergency department (ED) presentations among children. None have examined whether a dose-response effect exists between grass pollen levels and these asthma exacerbations. OBJECTIVES: To examine the association between increasing ambient levels of grass pollen and asthma ED presentations in children. To determine whether these associations are seen only after a thunderstorm, or whether grass pollen levels have a consistent influence on childhood asthma ED visits during the season. METHODS: A short time series ecological study was conducted for asthma presentations to ED among children in Melbourne, Victoria, and grass pollen, meteorological and air quality measurements recorded during the selected 2003 period. A semi-parametric Poisson regression model was used to examine dose-response associations between daily grass pollen levels and mean daily ED attendance for asthma. RESULTS: A smoothed plot suggested a dose-response association. As ambient grass pollen increased to about 19 grains/m(3) , the same day risk of childhood ED presentations also increased linearly (P < 0.001). Grass pollen levels were also associated with an increased risk in asthma ED presentations on the following day (lag 1, P < 0.001). CONCLUSION: This is the first study to establish a clear relationship between increased risk of childhood asthma ED attendance and levels of ambient grass pollen below 20 grains/m(3) , independent of any impact of thunderstorm-associated asthma. These findings have important implications for patient care, such as asthma management programs that notify the general public regarding periods of high grass pollen exposure, as well as defining the timing of initiation of pollen immunotherapy.

Vestibulo-oculomotor behaviour in rats following a transient unilateral vestibular loss induced by lidocaine.

The effects of a transient vestibular nerve blockade, achieved by intra-tympanic instillation of lidocaine, were studied in rats by recording horizontal eye movements in darkness. Evaluation of the dose-response relationship showed that a maximal effect was attained with a concentration of 4% lidocaine. Within 15 min of lidocaine instillation, a vigorous spontaneous nystagmus was observed which reached maximal frequency and velocity of the slow phase after about 20 min. Subsequently, the nystagmus failed for approximately half an hour before it reappeared. This could be avoided by providing visual feedback in between the recordings in darkness or by a contralateral instillation of 2.5% lidocaine. It is suggested that the failure reflects an overload of the vestibulo-oculomotor circuits. After recovery from the nerve blockade, when the gaze was stable, dynamic vestibular tests were performed. They revealed that a decrease of the slow phase velocity gain and the dominant time constant during, respectively, sinusoidal- and step stimulation toward the unanaesthetised side, had developed with the nerve blockade. These modulations were impaired by a nodulo-uvulectomy but not by bilateral flocculectomy, which is consistent with the concept of vestibular habituation. A GABA(B) receptor antagonist, CGP 56433A, given systemically during the nerve blockade, aggravated the vestibular asymmetry. The same effect has previously been demonstrated in both short- (days) and long-term (months) compensated rats, by antagonising the GABA(B) receptor. In summary, this study provides the first observations of vestibulo-oculomotor disturbances during the first hour after a rapid and transient unilateral vestibular loss in the rat. By using this method, it is possible to study immediate behavioural consequences and possible neural changes that might outlast the nerve blockade.

Early compensation of vestibulo-oculomotor symptoms after unilateral vestibular loss in rats is related to GABA(B) receptor function.

The horizontal vestibulo-oculomotor reflex was studied in pigmented rats during the first 5 days after a unilateral chemical or surgical vestibular deafferentation. Spontaneous eye movements in darkness and slow phase velocity gain of compensatory eye movements during horizontal sinusoidal rotation were evaluated. The most evident vestibulo-oculomotor symptom immediately after a unilateral vestibular loss was a spontaneous nystagmus, which gradually abated during the following days. Further, an asymmetry between ipsi- and contra-lesional gains was evident during sinusoidal vestibular stimulation. Single systemic doses of the GABA(B) receptor antagonist [3-[1-(S)-[[3-(cyclohexylmethyl)-hydroxyphosphinoyl]-2-(S)-hydroxypropyl]amino]ethyl]-benzoic acid (CGP 56433A), the agonist baclofen, or the GABA(A) receptor agonist (4,5,6,7-tetrahydroisoxazolo-[5,4-c]-pyridin-3-ol (THIP) were given at different intervals after unilateral vestibular deafferentation. CGP 56433A highly aggravated the vestibulo-oculomotor symptoms, observed as an increase in spontaneous nystagmus and slow phase velocity gain asymmetry. This effect was most pronounced during the first 2 days after unilateral vestibular loss, when CGP 56433A even decompensated the vestibular system to the extent that all vestibular responses were abolished. Baclofen caused no effect during the first days after unilateral vestibular loss, but in parallel with the abatement of spontaneous nystagmus, the drug equilibrated or even reversed the remaining spontaneous nystagmus with corresponding effects on the slow-phase velocity gain asymmetry. The effects of baclofen were very similar after both chemical and surgical deafferentation. THIP caused a slight depression of all vestibular responses. All single dose effects of the drugs were transient. Altogether these results reveal that endogenous stimulation of GABA(B) receptors in GABA-ergic vestibulo-oculomotor circuits are important for reducing the vestibular asymmetry during the early period after unilateral vestibular deafferentation. A possible role for GABA(B) receptors in the reciprocal inhibitory commissural pathways in the vestibular nuclei is suggested.

GABA(B) receptors contribute to vestibular compensation after unilateral labyrinthectomy in pigmented rats.

The horizontal vestibulo-ocular reflex was studied in pigmented rats, which had been unilaterally, chemically labyrinthectomised 6-144 days previously. During this partially compensated stage after unilateral labyrinthectomy (UL), both static and dynamic deficits remain. The former was evaluated by recording of spontaneous eye movements in darkness, and the latter by estimating the slow-phase velocity (SPV) gain of compensatory eye movements during horizontal vestibular stimulation. The GABA(B) agonist baclofen caused a reversal of the remaining ipsilesional drift of the eyes in darkness into a nystagmus with a contralesional slow phase. The GABA(B) antagonist CGP 36742 caused a decompensation by exaggerating the remaining ipsilesional eye drift. Further, baclofen equilibrated or reversed the asymmetry between ipsi- and contralesional SPV gains during horizontal sinusoidal rotations at 0.2 Hz and 0.8 Hz. This was achieved by an increase in the ipsilesional gain and a decrease in the contralesional gain. The phase lead during sinusoidal rotation (0.2 Hz) was larger following rotation to the lesioned side than to the intact side in UL rats. This asymmetry was reversed by baclofen. CGP 36742 inhibited the effects of baclofen, while the antagonist per se aggravated SPV gain and phase lead asymmetries in UL rats during vestibular stimulation. Per- and post-rotatory nystagmus induced by velocity step stimulation revealed an imperfect velocity-storage function in UL animals, which was modulated by baclofen. An investigation of the baclofen effect on SPV gain asymmetry during different time intervals after chemical UL showed a completely developed effect on the 6th day. Bilateral flocculectomy did not alter the effects of baclofen on UL animals. It is concluded that physiological stimulation of GABA(B) receptors contributes to minimise the vestibulo-oculomotor asymmetry during the partially compensated period after UL. Administration of an agonist or an antagonist changes the asymmetry towards the ipsi- or contralesional side, possibly by altering the spontaneous neuronal activity in the bilateral medial vestibular nuclei. The results are compatible with a hypothesis, supported by in vitro slice experiments, that the efficacy of GABA(B) receptors is up-regulated on the ipsilesional side and down-regulated on the contralesional side.

Modulation of vestibular function by nociceptin/orphanin FQ: an in vivo and in vitro study.

The effects of nociceptin (orphanin FQ) on medial vestibular nucleus (MVN) neurons in vitro, and on vestibulo-ocular reflex (VOR) function in vivo, were investigated in order to determine the role of 'opioid-like orphan' (ORL1) receptors in modulating vestibular reflex function in the rat. Nociceptin (100 nM-1 microM) potently inhibited the spontaneous discharge of the majority (86%) of MVN neurons tested in the rat dorsal brainstem slice preparation in vitro. This inhibition was dose-dependent and persisted after blockade of synaptic transmission in low Ca2+/Co2+ medium. The inhibitory effects were insensitive to the opioid antagonist naloxone, but were effectively antagonised by the selective ORL1 receptor antagonist, [Phe1Psi(CH2-NH)Gly2]Nociceptin(1-13)NH2. The majority of MVN neurons ( approximately 70%) were inhibited by both nociceptin and the delta-opioid receptor agonist, [D-ala2, D-leu5]-enkephalin (DADLE), while a minority of cells (approximately 30%) were selectively responsive either to DADLE or to nociceptin, but not both. Co-application of nociceptin and DADLE to neurons that were responsive to both agonists, resulted in an inhibitory response that was the same as or less than the inhibition evoked by either agonist alone. Intracellular whole-cell patch clamp recordings from identified Type A and Type B MVN cells showed that both these cell types are responsive to nociceptin, which induced membrane hyperpolarisation and decrease in input resistance consistent with its known effects on membrane K currents in other cell types. In alert rats, i.c.v. injection of nociceptin caused a significant decrease in the gain of the hVOR and resulted in a prolongation of post-rotatory nystagmus in darkness. The decrease in VOR gain and the increase in the VOR time-constant was significant even at low doses of nociceptin which did not cause other observable behavioural effects. These findings demonstrate that endogenously released nociceptin may have a hitherto unexplored role in the functional modulation of the neural pathways that mediate vestibular reflexes in vivo.

Audiological disturbances caused by long-term exposure to industrial solvents. Relation to the diagnosis of toxic encephalopathy.

Sixty workers, consecutively admitted due to suspicion of solvent-induced chronic toxic encephalopathy (CTE), were investigated with pure-tone audiometry, determination of speech recognition of monosyllabic words and distorted speech and cortical response audiometry (CRA). Eighteen workers not exposed to occupational solvents and noise were also investigated. The scores in the distorted speech test were significantly lower and the CRA latencies were significantly longer in the solvent group than in the control group. There was no difference between the groups in the pure-tone and monosyllabic speech recognition tests. In the solvent group, 19 subjects had one or several pathological audiological test results (values exceeding the mean result of the control group by 2 SD). Independently of the audiological examination all the workers in the solvent group underwent the traditional clinical assessment of CTE, which is based on symptoms, history of exposure, clinical neurological examination and a neuropsychological investigation. They were classified in three groups--CTE, incipient CTE and non-CTE. There was no correlation between these groups and the audiological test results. A previous report on vestibular pathology in the same group of subjects and the present investigation on hearing deficits suggest that long-term exposure to solvents causes disturbances of the central pathways in the otovestibular system. Hitherto, no attention has been paid to these disturbances in the definition of the CTE syndrome.

Effects of the GABA agonists baclofen and THIP on long-term compensation in hemilabyrinthectomised rats.

Horizontal eye movements, elicited by sinusoidal rotation in darkness, were recorded with a magnetic search coil technique in pigmented rats, hemilabyrinthectomised 8-12 weeks before the investigation. Separate gains during rotation towards the lesioned side (LS) and the intact side (IS) were calculated by a computer program, demonstrating an asymmetry. Systemic single administration of the GABAB agonist baclofen caused a dose-related temporary rebalancing of the compensatory eye movements to the LS and the IS. At an optimal dose of 14 micromol/kg b.wt symmetry was achieved by excitation of eye movements during rotation to the LS and depression during rotation to the IS. Administration of the GABAA agonist THIP did not obviously reduce the asymmetry. It is suggested that stimulation of GABAB receptors modifies the tonic imbalance between the bilateral vestibular nuclei and/or the central processing of the input from the peripheral sensory organs.

Effects of toluene on tonic firing and membrane properties of rat medial vestibular nucleus neurones in vitro.

The effects of toluene on discharge rate and membrane properties of tonically active medial vestibular nucleus (MVN) neurones were investigated in an in vitro slice preparation of the dorsal brainstem of the rat. The majority of the cells (50/56) were inhibited in a dose-dependent manner by toluene. The inhibitory effects of toluene persisted after blockade of synaptic transmission. Complementary patch-clamp recordings showed that toluene caused a hyperpolarisation of 2-5 mV associated with an increase in membrane conductance. These findings indicate that toluene might interfere with specific ion channels or the receptors regulating them along the cell membrane. The effective toluene concentrations used in this experiment are comparable to the concentrations producing vestibulo-ocular disturbances in vivo.

A method for studying the effects of neurochemicals on long-term compensation in unilaterally labyrinthectomized rats.

A new method has been developed to study the influence of drugs and toxicants on long-term recovery of dynamics in the horizontal vestibulo-ocular reflex of the rat after hemilabyrinthectomy (HL). HL was performed by injecting sodium arsanilate into the middle ear. The lesion was confirmed by histology. Eye movements elicited by sinusoidal vestibular stimulation, in both light and darkness, were recorded by a search-coil technique and then analyzed by a computer program created with virtual instrument soft-ware, which calculated the gain of the slow-phase velocity (SPV) and the saccades para-meters (frequency, amplitude, and peak velocity) to the lesioned side and to the intact side separately. During the 2-10 week period after HL, repeated analysis of the spontaneous long-term recovery of such parameters revealed a slight but significant reduction of the post-HL asymmetry between SPV gain to the lesioned side and to the intact side. During the follow-up period, a post-HL increase of the phase lead remained unchanged. The reduced number of saccades/min was not completely restored. To test the usefulness of the experimental model for neurochemical investigation of such adaptation, we administered baclofen and toluene to rats 8-12 wk after hemilabyrinthectomy. Baclofen, a specific GABAB agonist, immediately restored the symmetry of SPV gain. By contrast, toluene, which has some effects on the central vestibular system that are related to GABAB transmission, aggravated the asymmetry in both the SPV gain and the number of saccades. We suggest that the experimental model would be useful for studying neurochemical mechanisms in vestibular adaptation processes.

Celiac disease: small-bowel enteroclysis findings in adult patients treated with a gluten-free diet.

PURPOSE: To correlate the radiologic, histopathologic, and clinical findings in patients with celiac disease after treatment with a glutenfree diet. MATERIALS AND METHODS: Pretreatment and follow-up enteroclysis radiographs from 15 adult patients with known celiac disease were reviewed. Diagnosis of celiac disease was made at adult age. Changes in small-bowel morphology were determined by comparing enteroclysis findings before and after treatment with a gluten-free diet and were correlated with histopathologic and clinical findings. RESULTS: Eight of 15 patients (group I) showed increased small-bowel abnormalities. All patients had increased symptoms, and all but one, whose condition had deteriorated, showed stable disease at biopsy. Group II patients (five of 15) showed improvement at follow-up enteroclysis. Biopsy findings showed improvement in small-bowel morphology in four patients and no change in one. Clinically, four patients showed improvement, and one had stable disease. Group III patients (two of 15) showed no change from initial to follow-up enteroclysis. Both showed partial atrophy, which was consistent with biopsy findings. In all patients, clinical symptoms correlated better with enteroclysis results (r = .48; P < .005) than they did with follow-up biopsy results (r = .18). True celiac disease-related malignancies and coexisting tumors occurred in 10 of 15 patients. CONCLUSION: Enteroclysis appears to be more reliable than does biopsy in evaluation of response to a gluten-free diet in adults with celiac disease.

Are the effects of toluene on the vestibulo and opto-ocular motor system inhibited by the action of GABAB antagonist CGP 35348?

The acute effects of toluene and a selective GABAB-antagonist, CGP 35348, on the vestibulo and opto-ocular motor (VOOM) system in rats were investigated by recording of compensatory eye-movements during vestibular and optokinetic stimulations. It has previously been demonstrated that toluene enhances the performance of the basic vestibulo-oculomotor reflex (VOR) and depresses the effects of the visual input to this reflex. It has been proposed that these effects are caused by alterations of the GABA-transmission system in the cerebellum. It has now been demonstrated that the exaggerating effects of toluene on the VOR, tested by angular horizontal acceleration/deceleration of the animals in darkness, are inhibited by CGP 35348 in a dose related way. On the contrary, the depressing effects on the visual input, tested by optokinetic stimulation, by angular acceleration/deceleration with a simultaneous conflicting visual stimulation and by eliciting saccades, could not be prevented by CGP 35348. The results support the hypothesis that toluene causes some of the effects on the VOOM system by influence on the GABA-transmission. The findings are in agreement with a recent report of increased levels of extracellular GABA in the cerebellar cortex during exposure to toluene.