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Enriched language exposure may benefit infants in the neonatal intensive care unit. We hypothesized that changes in neonatal electroencephalogram (EEG) coherence during sleep, in response to maternal voice exposure, predict language development. Convalescent neonates underwent 12-h polysomnography. A recording of the mother’s voice was randomized to continuous playback in the first or second 6 h. We calculated the imaginary coherence (ICOH—a measure of functional connectivity) between EEG leads. Spearman correlations were computed between ICOH and 18-month Bayley-III language scores. Thirty-five neonates were included (N = 18 33-to

In January 2019, a new plant-derived purified cannabidiol preparation, approved by the US Food and Drug Administration, became commercially available for patients ≥2 years old with Lennox-Gastaut syndrome or Dravet syndrome. Among our patients who were prescribed the new cannabidiol formulation, we observed several cases of thrombocytopenia and therefore embarked on this study. We conducted a single-center systematic chart review of all pediatric patients (

OBJECTIVE: Among older infants and children, sleep-disordered breathing (SDB) has negative neurocognitive consequences. We evaluated the frequency and potential impact of SDB among newborns who require intensive care. STUDY DESIGN: Term and near-term newborns at risk for seizures underwent 12-h attended polysomnography in the neonatal intensive care unit (NICU). Bayley Scales of Infant Development, third edition (Bayley-III) were administered at 18–22 months. RESULT: The 48 newborns (EGA 39.3 ± 1.6) had a median pediatric apnea-hypopnea index (AHI) of 10.1 (3.3–18.5) and most events were central (vs obstructive). Maternal and prenatal factors were not associated with AHI. Moreover, neonatal PSG results were not associated with Bayley-III scores (P > 0.05). CONCLUSION: SDB is common among term and near-term newborns at risk for seizures. Follow-up at ages when more nuanced testing can be performed may be necessary to establish whether neonatal SDB is associated with long-term neurodevelopmental disability.

Early diagnosis of autism spectrum disorder (ASD) has focused on differentiating children with ASD from neurotypical children. However, many children presenting with concern for ASD are ultimately diagnosed with language disorder (LD). This study aimed to identify differences in parent-rated development and behavior among children ages 2 to 5 years presenting with concern for ASD who were diagnosed with either ASD or LD. Children with ASD were rated as more socially withdrawn and more delayed in social development and self-help skills than those with LD. Parent-rated developmental delays were positively correlated with scores on an autism screening measure and with social withdrawal and pervasive developmental problems among children with ASD. Among those with LD, parent-rated social and self-help development were positively correlated with social withdrawal and attention problems. Thus, parent ratings of social withdrawal and development of social and self-help skills may facilitate differential diagnosis of ASD and LD in children ages 2 to 5 years.

Importance Studies of cranial ultrasonography and early childhood outcomes among cohorts of extremely preterm neonates have linked periventricular-intraventricular hemorrhage and cystic periventricular leukomalacia with adverse neurodevelopmental outcomes. However, the association between nonhemorrhagic ventriculomegaly and neurodevelopmental and behavioral outcomes is not fully understood. Objective To characterize the outcomes of extremely preterm neonates younger than 27 weeks’ gestational age who experienced nonhemorrhagic ventriculomegaly that was detected prior to 36 weeks’ postmenstrual age. Design, Setting, and Participants This longitudinal observational study was conducted at 16 centers of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network. Infants born prior to 27 weeks’ gestational age in any network facility between July 1, 2006, and June 30, 2011, were included if they had a cranial ultrasonogram performed prior to 36 weeks’ postmenstrual age. Comparisons were made between those with ventriculomegaly and those with normal cranial sonograms. Data analysis was completed from August 2013 to August 2017. Main Outcomes and Measures The main outcome was neurodevelopmental impairment, defined as a Bayley Scales of Infant and Toddler Development III cognitive score less than 70, moderate/severe cerebral palsy, a Gross Motor Function Classification System score of level 2 or more, vision impairment, or hearing impairment. Secondary outcomes included Bayley Scales of Infant and Toddler Development III subscores, components of neurodevelopmental impairment, behavioral outcomes, and death/neurodevelopmental impairment. Logistic regression was used to evaluate the association of ventriculomegaly with adverse outcomes while controlling for potentially confounding variables and center differences as a random effect. Linear regression was used similarly for continuous outcomes. Results Of 4193 neonates with ultrasonography data, 300 had nonhemorrhagic ventriculomegaly (7%); 3045 had normal cranial ultrasonograms (73%), 775 had periventricular-intraventricular hemorrhage (18.5%), and 73 had cystic periventricular leukomalacia (1.7%). Outcomes were available for 3008 of 3345 neonates with ventriculomegaly or normal scans (90%). Compared with normal cranial ultrasonograms, ventriculomegaly was associated with lower gestational age, male sex, and bronchopulmonary dysplasia, late-onset sepsis, meningitis, necrotizing enterocolitis, and stage 3 retinopathy of prematurity. After adjustment, neonates with ventriculomegaly had higher odds of neurodevelopmental impairment (odds ratio [OR], 3.07; 95% CI, 2.13-4.43), cognitive impairment (OR, 3.23; 95% CI, 2.09-4.99), moderate/severe cerebral palsy (OR, 3.68; 95% CI, 2.08-6.51), death/neurodevelopmental impairment (OR, 2.17; 95% CI, 1.62-2.91), but not death alone (OR, 1.09; 95% CI, 0.76-1.57). Behavioral outcomes did not differ. Conclusions and Relevance Nonhemorrhagic ventriculomegaly is associated with increased odds of neurodevelopmental impairment among extremely preterm neonates.

Objectives The neurological examination of critically ill neonates is largely limited to reflexive behavior. The exam often ignores sleep-wake physiology that may reflect brain integrity and influence long-term outcomes. We assessed whether polysomnography and concurrent cerebral near-infrared spectroscopy (NIRS) might improve prediction of 18-month neurodevelopmental outcomes. Methods Term newborns with suspected seizures underwent standardized neurologic examinations to generate Thompson scores and had 12-hour bedside polysomnography with concurrent cerebral NIRS. For each infant, the distribution of sleep-wake stages and electroencephalogram delta power were computed. NIRS-derived fractional tissue oxygen extraction (FTOE) was calculated across sleep-wake stages. At age 18-22 months, surviving participants were evaluated with Bayley Scales of Infant Development (Bayley-III), 3rd edition. Results Twenty-nine participants completed Bayley-III. Increased newborn time in quiet sleep predicted worse 18-month cognitive and motor scores (robust regression models, adjusted r2 = 0.22, p = .007, and 0.27, .004, respectively). Decreased 0.5-2 Hz electroencephalograph (EEG) power during quiet sleep predicted worse 18-month language and motor scores (adjusted r2 = 0.25, p = .0005, and 0.33, .001, respectively). Predictive values remained significant after adjustment for neonatal Thompson scores or exposure to phenobarbital. Similarly, an attenuated difference in FTOE, between neonatal wakefulness and quiet sleep, predicted worse 18-month cognitive, language, and motor scores in adjusted analyses (each p Conclusions These prospective, longitudinal data suggest that inefficient neonatal sleep-as quantified by increased time in quiet sleep, lower electroencephalogram delta power during that stage, and muted differences in FTOE between quiet sleep and wakefulness-may improve prediction of adverse long-term outcomes for newborns with neurological dysfunction.

Rationale and Objectives The purposes of this study were to retrospectively identify various etiologies underlying intracranial hemorrhages (ICHs) in term infants aged Materials and Methods A retrospective review of the medical records and computed tomographic studies of the head in 798 term infants aged 0 to 24 months with suspected or known ICHs was conducted. Results ICHs were present in 195 of the 798 infants (24%). More than one type of ICH was present in 32%. Subdural hemorrhage was the most frequent type of ICH, occurring in 63% of the infants. Good clinical outcomes were present in 49% of the infants but varied depending on the location, etiology, and timing of the ICH. Conclusion The incidence of various etiologies of ICH depended on the ages of the infants. The overall clinical outcomes were good, with no long-term sequelae in half of the infants presenting with ICHs. In infants aged >4 weeks presenting with ICHs, special attention should be given to the possibility of nonaccidental trauma etiology, because this is common and has worse long-term outcomes.

Objective To review the clinical presentation and neuroimaging findings in patients with high clinical suspicion for non-accidental trauma (NAT) of the head, to investigate associations between imaging findings and long-term neurologic outcome in abused children. Study design A retrospective review of 57 cases of NAT of the head from a single institution was performed. Neuroimaging studies (computed tomography [CT] and magnetic resonance imaging [MRI]) were reviewed by a senior neuroradiologist, a neuroradiology fellow, and a radiology resident. Clinical history and physical findings, including retinal examination, imaging, and follow-up assessment, were reviewed. Results The mean time between the patient's arrival at the hospital and CT and MRI imaging was 2.9 hours and 40.6 hours, respectively. The most common clinical presentation was mental status changes, seen in 47% of patients. The most common neuroimaging finding was subdural hematoma, seen in 86% of patients. In the 47 patients who underwent both MRI and CT, 1 case of suspected NAT was missed on head CT. CT detected signs of global ischemia in all 11 patients who died (mean time after arrival at the hospital until undergoing CT, 1.1 hours). MRI detected additional signs of injury in patients who developed mild to moderate developmental delay. Conclusion CT was able to detect evidence of NAT of the head in 56 of 57 abused children included in our cohort and predicted severe neurologic injury and mortality. MRI was useful in detecting additional evidence of trauma, which can be helpful in risk stratification for neurologic outcomes as well in providing confirming evidence of repeated injury.

Genetic heterogeneity in neurologic disorders has been an obstacle to phenotype-based diagnostic testing. The authors hypothesized that information compiled via whole exome sequencing will improve clinical diagnosis and management of pediatric neurology patients. The authors performed a retrospective chart review of patients evaluated in the University of Michigan Pediatric Neurology clinic between 6/2011 and 6/2015. The authors recorded previous diagnostic testing, indications for whole exome sequencing, and whole exome sequencing results. Whole exome sequencing was recommended for 135 patients and obtained in 53 patients. Insurance barriers often precluded whole exome sequencing. The most common indication for whole exome sequencing was neurodevelopmental disorders. Whole exome sequencing improved the presumptive diagnostic rate in the patient cohort from 25% to 48%. Clinical implications included family planning, medication selection, and systemic investigation. Compared to current second tier testing, whole exome sequencing can result in lower long-term charges and more timely diagnosis. Overcoming barriers related to whole exome sequencing insurance authorization could allow for more efficient and fruitful diagnostic neurological evaluations.

Nonaccidental head injury can be a very serious result of child abuse with the clinical outcome being poor and including mental retardation, long-term disability and even death. Skull radiographs, head CT and increasingly MRI are very useful tools in making this very serious diagnosis. Radiologists must be familiar with the radiologic patterns of child abuse and must maintain a high level of suspicion. We review and present several of the common radiologic findings in pediatric nonaccidental head injury.

PURPOSE OF REVIEW Newborn screening for neurometabolic disorders offers a unique and promising opportunity to practice preventive medicine in children with diverse inborn errors of metabolism. The benefits of the early identification and presymptomatic treatment of these disorders are now recognized. RECENT FINDINGS The rapid pace of developments in the field of expanded newborn screening has been made possible by technological advances in the ability to detect multiple compounds diagnostic of diverse inborn errors of metabolism in neonatal dried blood specimens. Launched by the success of newborn screening for phenylketonuria, experts in this area are optimistic that further public health benefits will follow the same pathway. This review highlights the population model and public health issues inherent in advances in newborn screening for selected neurometabolic disorders. Current and future diagnostic and therapeutic, as well as social and ethical, dilemmas are discussed. SUMMARY Newborn screening represents one of the major child health advances of this past century. As developments in the field of expanded newborn screening for neurometabolic disease progress forward, the long-term success of this important project will pose future challenges and opportunities.

Wilson's disease is a genetic disorder of copper metabolism with a hepatic or neurologic presentation. A hepatic presentation is more common in young children. Neurologic Wilson's disease often manifests as a movement disorder with dystonia, tremor, and dysarthria. Psychiatric or behavioral symptoms can also be a presenting feature of Wilson's disease. We describe an atypical neurologic presentation in a prepubertal child with minimal hepatic involvement; in which transient hemiparesis and encephalopathy dominated her initial neurologic presentation. Brain magnetic resonance imaging revealed extensive cortical and subcortical signal change, in addition to the classical basal ganglia signal abnormality observed in Wilson's disease. She was treated with oral tetrathiomolybdate anticopper therapy, followed by zinc maintenance. Her clinical status and brain imaging improved considerably at 1 year after treatment initiation. Neurologic Wilson's disease may have diverse presentations, and should be considered in children who present with cortical features and signal change on magnetic resonance imaging.

Central nervous system manifestations of acute myeloid leukemia are rare at presentation. Acute cranial nerve findings on neurologic examination can be indications for brain imaging. Magnetic resonance imaging can highlight cranial nerves emerging from the brainstem, particularly if they are gadolinium-enhanced or thickened. We describe a 15-month-old girl with acute unilateral ophthalmoplegia as the presenting sign of acute myeloid leukemia. Her presentation emphasizes the importance of appropriate laboratory and radiographic evaluation in a toddler with new-onset strabismus, which may be discounted as a previously unrecognized or benign finding.

Quantitative receptor autoradiography was used to measure the laminar distribution of [ 3 H]glycine and [ 3 H]glutamate binding to the N-methyl-D-aspartate (NMDA) receptor complex, [ 3 H]D,L-a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) binding to the AMPA receptor, and [ 3 H]flunitrazepam binding to the benzodiazepine (BDZ) receptor in three areas of visual cortex in control and Alzheimer's disease (AD) postmortem human brains (primary or striate visual cortex, visual association cortex, and higher-order visual association cortex, corresponding to Brodmami Areas 17, 18, and 21, respectively). In Area 17, binding to the NMDA, AMPA, and BDZ receptors was not significantly altered in the AD brains (except in layer VI for [ 3 H]glycine and layer III for [ 3 H]AMPA, where binding was reduced in the AD brains). Ligand binding to the two EAA receptors in Area 18 was, however significantly reduced in the AD brains (layers I through III for [ 3 h]glycine and layers III through VI for [ 3 H]AMPA). In Area 21, binding to both the NMDA and BDZ receptors but not to the AMPA receptor, was significantly reduced in almost all laminae of the AD brains (layers I through VI for [ 3 H]glycine and layers I through V for [ 3 H]flunitrazepam). This hierarchical pattern of laminar binding loss with increasing complexity of association visual cortices is consistent with the increasing numbers of neurofibrillary tangles found in those areas, implicating NMDA and BDZ receptor bearing cells in AD neuropathology. AMPA receptor losses do not parallel the pathology, suggesting that AMPA receptors are not directly correlated with the pathology.

It has become clear that serum "free" copper (the copper not bound to ceruloplasmin in the blood) is the copper causing copper toxicity in Wilson's disease. But up until now, free copper has not been closely followed during initiation of anticopper therapy in neurologically presenting patients. During this period of initial therapy, the future fate of these patients hangs in the balance-if they worsen neurologically as often happens with penicillamine or trientine therapy, many never recover. We hypothesize that free copper levels are a biological marker of clinical outcome in these patients. In this article, we evaluate the control of free copper in 3 studies of initial anticopper treatment in neurologically presenting Wilson's disease patients. The first (study 1) is a 55-patient open-label trial of tetrathiomolybdate, the second (study 2) is a 48-patient double-blind trial comparing tetrathiomolybdate and trientine, and the third (study 3) is a 40-patient double-blind comparison of 2 disease regimens of tetrathiomolybdate. Free copper levels were determined by subtracting ceruloplasmin and tetrathiomolybdate bound copper from total serum copper. Tetrathiomolybdate showed very strong control of free copper levels over the 8 weeks of treatment in the 55-patient open-label study (study 1), reducing it to a mean value of about one fourth, or less, of baseline. In the tetrathiomolybdate/trientine double blind (study 2), tetrathiomolybdate again showed good control of free copper levels over 8 weeks of treatment, which is significantly better than trientine. In the trientine arm of study 2, mean free copper levels actually went up during trientine therapy. The 5 patients who neurologically worsened on trientine therapy over 8 weeks of treatment showed significant spikes in serum free copper levels associated in time with their neurologic worsening. Patients who did not worsen neurologically generally did not show significant spikes in free copper. Tetrathiomolybdate controlled copper less well in the dose regimen study (study 3) than in the previous 2 studies of tetrathiomolybdate treatment, probably because of a change in the way "away from food" tetrathiomolybdate was given.

Background: The initial treatment of the neurologic presentation of Wilson's disease is problematic. Penicillamine, used for years on most patients, causes neurologic worsening in up to half of such patients, and half of those who worsen never recover. Zinc, ideal for maintenance therapy, is too slow for these acutely ill patients. We have developed tetrathiomolybdate (TM) for this type of patient, and it has worked well in open label studies. Trientine, another anticopper drug on the market approved for penicillamine intolerant patients, had not been tried in this type of patient. Here, we report on a double blind trial of TM versus trientine in the neurologically presenting Wilson's disease patient. Design and Methods: The study was a double blind design in which patients received either TM plus zinc, or trientine plus zinc, for 8 weeksThis study was originally published in reference 1. Patients were accepted if they presented with neurologic symptoms from Wilson's disease, if they had not been treated longer than 4 weeks with penicillamine or trientine. Patients were followed in the hospital for the 8 weeks of treatment with weekly semiquantitative neurologic and speech examinations, to evaluate possible neurologic worsening. They also had blood and urine studies done weekly. At discharge from hospital they were continued on zinc maintenance therapy, and returned at yearly intervals for 3 years for further evaluation. Results: Twenty-three patients were entered into the trientine arm and 6 reached criteria for neurologic deterioration, while 25 patients were entered into the TM arm and only 1 deteriorated (p < 0.05). One patient on trientine had an adverse event while 7 on TM had adverse events. All adverse events were mild. Four patients in the trientine arm died during follow-up, 3 having shown initial neurologic deterioration, 2 patients in the TM arm died. In those patients who did not deteriorate or die, neurologic and speech recovery over 3 years was good. Interpretation: TM is a superior choice to trientine for the initial therapy of neurologic Wilson's disease.

The aim of this study was to evaluate the added utility of gadolinium administration in the magnetic resonance imaging evaluation of developmental delay in children less than 2 years of age. A computerized retrospective study identified all brain magnetic resonance imaging examinations using gadolinium performed at our institution from 1995–2002 for children under the age of 2 years. Review of the clinical records and magnetic resonance imaging reports identified 170 brain magnetic resonance imaging examinations that were performed for developmental delay. Magnetic resonance imaging studies with enhancing lesions were reviewed by two staff neuroradiologists and two radiology residents. Contrast administration was rated as essential, helpful, or not helpful for each study. In the 107 patients in whom developmental delay was the primary concern, there were no cases in which the findings would have been missed without gadolinium administration. In the 63 patients in whom developmental delay was a secondary concern, there were several cases (11%) where contrast was helpful but not essential in reaching a radiologic diagnosis. In conclusion, intravenous gadolinium has an extremely low yield in children under the age of 2 where developmental delay is the primary concern. In young children for whom developmental delay is a secondary concern, we advocate the use of gadolinium particularly where tumor or infection is clinically suspected.

The Chiari I congenital malformation is characterized by caudal displacement of the cerebellar tonsils through the cervical canal. Although this malformation is often asymptomatic, coexisting syringomyelia can result in neurologic symptoms. We report a case of progressive ataxia with brainstem dysfunction in an adolescent female manifesting a severe Chiari I malformation with syrinx. Chiari decompression 4 years after initial presentation led to rapid improvement in most of her long-term symptoms. This case demonstrates the importance of consideration of Chiari I with syringomyelia in the differential diagnosis of progressive ataxia and brainstem symptoms.

Maple syrup urine disease [MSUD] is a rare inborn error of metabolism inherited as an autosomal recessive trait through mutations in any of three different genes that encode components of the branched chain alpha-ketoacid dehydrogenase [BCKD] complex. In this work, the genotype of affected individuals was correlated with their clinical histories. These individuals were diagnosed and followed in a single centralized clinic, and their molecular genetic characterization was done by one laboratory. Three individuals had mutant alleles in the gene for the E1alpha component, five had mutations in the gene for E1beta, and three had mutations in the gene for E2. The results emphasize the diversity of the molecular and clinical presentations for individuals with MSUD and support the complexity of diseases termed "single gene traits." Of primary importance is early identification of at risk infants through newborn screening programs to minimize many of the complications associated with this protein intolerance. Attention to abnormal neurological signs in the neonate or evidence of neurological decompensation in older infants and children by a centralized medical management team minimizes permanent brain damage and improves survival.

Objective: To compare tetrathiomolybdate and trientine in treating patients with the neurologic presentation of Wilson disease for the frequency of neurologic worsening, adverse effects, and degree of neurologic recovery. Design:A randomized, double-blind, controlled, 2-arm study of 48 patients with the neurologic presentation of Wilson disease. Patients either received 500 mg of trientine hydrochloride 2 times per day or 20 mg of tetrathiomolybdate 3 times per day with meals and 20 mg 3 times per day between meals for 8 weeks. All patients received50mgofzinc2timesperday.Patientswerehospitalized for 8 weeks, with neurologic and speech function assessed weekly; discharged taking 50 mg of zinc 3 times per day, and returned annually for follow-up. Setting: A university hospital referral setting. Patients:Primarily newly diagnosed patients with Wilson disease presenting with neurologic symptoms who had not been treated longer than 4 weeks with an anticopper drug. Intervention:Treatment with either trientine plus zinc or tetrathiomolybdate plus zinc. Main Outcome Measures: Neurologic function was assessed by semiquantitative neurologic and speech examinations.Drugadverseeventswereevaluatedbyblood cell counts and biochemical measures. Results: Six of 23 patients in the trientine arm and 1 of 25patientsinthetetrathiomolybdatearmunderwentneurologic deterioration (P.05). Three patients receiving tetrathiomolybdate had adverse effects of anemia and/or leukopenia, and 4 had further transaminase elevations. One patient receiving trientine had an adverse effect of anemia.Fourpatientsreceivingtrientinediedduringfollow-up, 3 having shown initial neurologic deterioration.Neurologicandspeechrecoveryduringa3-yearfollow-up period were quite good. Conclusion:Tetrathiomolybdate is a better choice than trientine for preserving neurologic function in patients who present with neurologic disease. ClinicalTrials.gov Identifier: NCT00004339

Biotinidase deficiency is a defect in the recycling of the vitamin biotin. Biotin supplementation can markedly improve the neurological and cutaneous symptoms of affected children and prevent symptoms in children identified by newborn screening or treated since birth. We have determined thirteen novel mutations in children with the disorder. Two nonsense mutations, eight single missense mutations, three allelic double missense mutations, and two are polymorphisms were identified in the biotinidase gene (BTD). One of the missense mutations, c.734G>A (p. C245Y), is the first to be reported that alters the cysteine in the putative location crucial for ester formation and binding of the biotinyl-moiety in the active site of the enzyme. These mutations add to the growing list of mutations that are helping to delineate structure/function relationships of the enzyme.

Objective: To test the efficacy and toxic effects of ammonium tetrathiomolybdate in the initial treatment of a relatively large series of patients with neurologic symptoms and signs caused by Wilson disease. Two key aspects of efficacy are to preserve the neurologic function present at the onset of therapy and to maximize the opportunity for long-term recovery. Design: An open study of 33 patients treated for 8 weeks each, including further follow-up data on the original 17 patients. Neurologic function was evaluated by frequent quantitative neurologic and speech pathology examinations. Several copper-related variables were studied to evaluate the effect of the drug on copper, and several biochemical and clinical variables were studied to evaluate potential toxic effects. Patients were then followed up at yearly intervals, with follow-up periods of 1 to 8 years reported. Setting: A university hospital referral setting. Intervention: Patients were generally treated for 8 weeks with tetrathiomolybdate, followed by zinc maintenance therapy. Main Outcome Measures: Neurologic function was evaluated by quantitative neurologic and motor speech examinations and magnetic resonance imaging scans of the brain. Results: During the 8 weeks of tetrathiomolybdate administration, only 1 of the 33 patients showed deterioration in neurologic function. Copper status and potential further toxic effects were generally well controlled quickly. Evaluation of data from individual patients revealed evidence of a toxic side effect in only 1 patient, who exhibited reversible anemia. During the ensuing period of follow-up of 1 to 6 years, neurologic recovery in most patients was good to excellent. Conclusions: Tetrathiomolybdate appears to be an excellent form of initial treatment in patients with Wilson disease who present with neurologic symptoms and signs. In contrast to penicillamine therapy, initial treatment with tetrathiomolybdate rarely allows further, often irreversible, neurologic deterioration.

The ATP-dependent uptake of l-glutamate into synaptic vesicles has been well characterized, implicating a key role for synaptic vesicles in glutamatergic neurotransmission. In the present study, we provide evidence that vesicular glutamate uptake is selectively inhibited by the pep-tide-containing halogenated ergot bromocriptine. It is the most potent inhibitor of the agents tested; the IC5o was de-termined to be 22 μM. The uptake was also inhibited by other ergopeptines such as ergotamine and ergocristine, but with less potency. Ergots devoid of the peptide moiety, however, such as ergonovine, lergotrile, and methysergide, had little or no effect. Although bromocriptine is known to elicit dopaminergic and serotonergic effects, its inhibitory effect on vesicular glutamate uptake was not mimicked by agents known to interact with dopamine and serotonin receptors. Kinetic data suggest that bromocriptine competes with glutamate for the glutamate binding site on the glutamate trans-locator. It is proposed that this inhibitor could be useful as a prototype probe in identifying and characterizing the vesicular glutamate translocator, as well as in developing a more specific inhibitor of the transport system.