The G protein-biased κ-opioid receptor agonist RB-64 is analgesic with a unique spectrum of activities in vivo.

The hypothesis that functionally selective G protein-coupled receptor (GPCR) agonists may have enhanced therapeutic benefits has revitalized interest for many GPCR targets. In particular, although κ-opioid receptor (KOR) agonists are analgesic with a low risk of dependence and abuse, their use is limited by a propensity to induce sedation, motor incoordination, hallucinations, and dysphoria-like states. Several laboratories have produced a body of work suggesting that G protein-biased KOR agonists might be analgesic with fewer side effects. Although that has been an intriguing hypothesis, suitable KOR-selective and G protein-biased agonists have not been available to test this idea. Here we provide data using a G protein-biased agonist, RB-64 (22-thiocyanatosalvinorin A), which suggests that KOR-mediated G protein signaling induces analgesia and aversion, whereas ß-arrestin-2 signaling may be associated with motor incoordination. Additionally, unlike unbiased KOR agonists, the G protein-biased ligand RB-64 does not induce sedation and does not have anhedonia-like actions, suggesting that a mechanism other than G protein signaling mediates these effects. Our findings provide the first evidence for a highly selective and G protein-biased tool compound for which many, but not all, of the negative side effects of KOR agonists can be minimized by creating G protein-biased KOR agonists.

Different contributions of dopamine D1 and D2 receptor activity to alcohol potentiation of brain stimulation reward in C57BL/6J and DBA/2J mice.

C57BL/6J (C57) and DBA/2J (DBA) mice respond differently to drugs that affect dopamine systems, including alcohol. The current study compared effects of D1 and D2 receptor agonists and antagonists, and the interaction between D1/D2 antagonists and alcohol, on intracranial self-stimulation in male C57 and DBA mice to determine the role of dopamine receptors in the effects of alcohol on brain stimulation reward (BSR). In the initial strain comparison, dose effects on BSR thresholds and maximum operant response rates were determined for the D1 receptor agonist SKF-82958 (±-6-chloro-7,8-dihydroxy-3-allyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine; 0.1-0.56 mg/kg) and antagonist SCH 23390 (+-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepinehydrochloride; 0.003-0.056 mg/kg), and the D2 receptor agonist quinpirole (0.1-3.0 mg/kg) and antagonist raclopride (0.01-0.56 mg/kg). For the alcohol interaction, SCH 23390 (0.003 mg/kg) or raclopride (0.03 mg/kg) was given before alcohol (0.6-2.4 g/kg p.o.). D1 antagonism dose-dependently elevated and SKF-82958 dose-dependently lowered BSR threshold in both strains; DBA mice were more sensitive to SKF-82958 effects. D2 antagonism dose-dependently elevated BSR threshold only in C57 mice. Low doses of quinpirole elevated BSR threshold equally in both strains, whereas higher doses of quinpirole lowered BSR threshold only in C57 mice. SCH 23390, but not raclopride, prevented lowering of BSR threshold by alcohol in DBA mice. Conversely, raclopride, but not SCH 23390, prevented alcohol potentiation of BSR in C57 mice. These results extend C57 and DBA strain differences to D1/D2 sensitivity of BSR, and suggest differential involvement of D1 and D2 receptors in the acute rewarding effects of alcohol in these two mouse strains.

Levetiracetam results in increased and decreased alcohol drinking with different access procedures in C57BL/6J mice.

The antiepileptic levetiracetam (LEV) has been investigated for the treatment of alcohol abuse. However, little is known about how LEV alters the behavioral effects of alcohol in laboratory animals. The acute effects of LEV on alcohol drinking by male C57BL/6J mice were investigated using two different drinking procedures, limited access [drinking-in-the-dark (DID)] and intermittent access (IA) drinking. In the first experiment (DID), mice had access to a single bottle containing alcohol or sucrose for 4 h every other day. In the second experiment (IA), mice had IA to two bottles, one containing alcohol or sucrose and one containing water, for 24 h on Monday, Wednesday, and Friday. In both experiments, mice were administered LEV (0.3-100 mg/kg intraperitoneally) or vehicle 30 min before access to the drinking solutions. In the DID mice, LEV increased alcohol intake from 4.3 to 5.4 g/kg, whereas in the IA mice LEV decreased alcohol intake from 4.8 to 3.0 g/kg in the first 4 h of access and decreased 24 h alcohol intake from 20 to ∼15 g/kg. These effects appear specific to alcohol, as LEV did not affect sucrose intake in either experiment. LEV appears to differentially affect drinking in animal models of moderate and heavier alcohol consumption.

Advancing clinical development for neuronopathic Hunter syndrome through a quantitatively-driven reverse translation framework.

A quantitatively-driven evaluation of existing clinical data and associated knowledge to accelerate drug discovery and development is a highly valuable approach across therapeutic areas, but remains underutilized. This is especially the case for rare diseases for which development is particularly challenging. The current work outlines an organizational framework to support a quantitatively-based reverse translation approach to clinical development. This approach was applied to characterize predictors of the trajectory of cognition in Hunter syndrome (Mucopolysaccharidosis Type II; MPS-II), a rare X-linked lysosomal storage disorder, highly heterogeneous in its course. Specifically, we considered ways to refine target populations based on age, cognitive status, and biomarkers, that is, cerebrospinal fluid glycosaminoglycans (GAG), at trial entry. Data from a total of 138 subjects (age range 2.5 to 10.1 years) from Takeda-sponsored internal studies and external natural history studies in MPS-II were included. Quantitative analyses using mixed-effects models were performed to characterize the relationships between neurocognitive outcomes and potential indicators of disease progression. Results revealed a specific trajectory in cognitive development across age with an initial progressive phase, followed by a plateau between 4 and 8 years and then a variable declining phase. Additionally, results suggest a faster decline in cognition among subjects with lower cognitive scores or with higher cerebrospinal fluid GAG at enrollment. These results support differences in the neurocognitive course of MPS-II between distinct groups of patients based on age, cognitive function, and biomarker status at enrollment. These differences should be considered when designing future clinical trials.

Effects of sulfatide on peripheral nerves in metachromatic leukodystrophy.

OBJECTIVE: To evaluate the longitudinal correlations between sulfatide/lysosulfatide levels and central and peripheral nervous system function in children with metachromatic leukodystrophy (MLD) and to explore the impact of intravenous recombinant human arylsulfatase A (rhASA) treatment on myelin turnover. METHODS: A Phase 1/2 study of intravenous rhASA investigated cerebrospinal fluid (CSF) and sural nerve sulfatide levels, 88-item Gross Motor Function Measure (GMFM-88) total score, sensory and motor nerve conduction, brain N-acetylaspartate (NAA) levels, and sural nerve histology in 13 children with MLD. Myelinated and unmyelinated nerves from an untreated MLD mouse model were also analyzed. RESULTS: CSF sulfatide levels correlated with neither Z-scores for GMFM-88 nor brain NAA levels; however, CSF sulfatide levels correlated negatively with Z-scores of nerve conduction parameters, number of large (≥7 µm) myelinated fibers, and myelin/fiber diameter slope, and positively with nerve g-ratios and cortical latencies of somatosensory-evoked potentials. Quantity of endoneural litter positively correlated with sural nerve sulfatide/lysosulfatide levels. CSF sulfatide levels decreased with continuous high-dose treatment; this change correlated with improved nerve conduction. At 26 weeks after treatment, nerve g-ratio decreased by 2%, and inclusion bodies per Schwann cell unit increased by 55%. In mice, abnormal sulfatide storage was observed in non-myelinating Schwann cells in Remak bundles of sciatic nerves but not in unmyelinated urethral nerves. INTERPRETATION: Lower sulfatide levels in the CSF and peripheral nerves correlate with better peripheral nerve function in children with MLD; intravenous rhASA treatment may reduce CSF sulfatide levels and enhance sulfatide/lysosulfatide processing and remyelination in peripheral nerves.

Dystonia in neurodegeneration with brain iron accumulation: outcome of bilateral pallidal stimulation.

Neurodegeneration with brain iron accumulation encompasses a heterogeneous group of rare neurodegenerative disorders that are characterized by iron accumulation in the brain. Severe generalized dystonia is frequently a prominent symptom and can be very disabling, causing gait impairment, difficulty with speech and swallowing, pain and respiratory distress. Several case reports and one case series have been published concerning therapeutic outcome of pallidal deep brain stimulation in dystonia caused by neurodegeneration with brain iron degeneration, reporting mostly favourable outcomes. However, with case studies, there may be a reporting bias towards favourable outcome. Thus, we undertook this multi-centre retrospective study to gather worldwide experiences with bilateral pallidal deep brain stimulation in patients with neurodegeneration with brain iron accumulation. A total of 16 centres contributed 23 patients with confirmed neurodegeneration with brain iron accumulation and bilateral pallidal deep brain stimulation. Patient details including gender, age at onset, age at operation, genetic status, magnetic resonance imaging status, history and clinical findings were requested. Data on severity of dystonia (Burke Fahn Marsden Dystonia Rating Scale-Motor Scale, Barry Albright Dystonia Scale), disability (Burke Fahn Marsden Dystonia Rating Scale-Disability Scale), quality of life (subjective global rating from 1 to 10 obtained retrospectively from patient and caregiver) as well as data on supportive therapy, concurrent pharmacotherapy, stimulation settings, adverse events and side effects were collected. Data were collected once preoperatively and at 2-6 and 9-15 months postoperatively. The primary outcome measure was change in severity of dystonia. The mean improvement in severity of dystonia was 28.5% at 2-6 months and 25.7% at 9-15 months. At 9-15 months postoperatively, 66.7% of patients showed an improvement of 20% or more in severity of dystonia, and 31.3% showed an improvement of 20% or more in disability. Global quality of life ratings showed a median improvement of 83.3% at 9-15 months. Severity of dystonia preoperatively and disease duration predicted improvement in severity of dystonia at 2-6 months; this failed to reach significance at 9-15 months. The study confirms that dystonia in neurodegeneration with brain iron accumulation improves with bilateral pallidal deep brain stimulation, although this improvement is not as great as the benefit reported in patients with primary generalized dystonias or some other secondary dystonias. The patients with more severe dystonia seem to benefit more. A well-controlled, multi-centre prospective study is necessary to enable evidence-based therapeutic decisions and better predict therapeutic outcomes.

Digital endpoints for self-administered home-based functional assessment in pediatric Friedreich's ataxia.

BACKGROUND: Friedreich's ataxia is an inherited, progressive, neurodegenerative disease that typically begins in childhood. Disease severity is commonly assessed with rating scales, such as the modified Friedreich's Ataxia Rating Scale, which are usually administered in the clinic by a neurology specialist. OBJECTIVE: This study evaluated the utility of home-based, self-administered digital endpoints in children with Friedreich's ataxia and unaffected controls and their relationship to standard clinical rating scales. METHODS: In a cross-sectional study with 25 participants (13 with Friedreich's ataxia and 12 unaffected controls, aged 6-15 years), home-based digital endpoints that reflect activities of daily living were recorded over 1 week. Domains analyzed were hand motor function with a digitized drawing, automated analysis of speech with a recorded oral diadochokinesis test, and gait and balance with wearable sensors. RESULTS: Hand-drawing and speech tests were easy to conduct and generated high-quality data. The sensor-based gait and balance tests suffered from technical limitations in this study setup. Several parameters discriminated between groups or correlated strongly with modified Friedreich's Ataxia Rating Scale total score and activities of daily living total score in the Friedreich's ataxia group. Hand-drawing parameters also strongly correlated with standard 9-hole peg test scores. INTERPRETATION: Deploying digital endpoints in home settings is feasible in this population, results in meaningful and robust data collection, and may allow for frequent sampling over longer periods of time to track disease progression. Care must be taken when training participants, and investigators should consider the complexity of the tasks and equipment used.

Definition and classification of hyperkinetic movements in childhood.

Hyperkinetic movements are unwanted or excess movements that are frequently seen in children with neurologic disorders. They are an important clinical finding with significant implications for diagnosis and treatment. However, the lack of agreement on standard terminology and definitions interferes with clinical treatment and research. We describe definitions of dystonia, chorea, athetosis, myoclonus, tremor, tics, and stereotypies that arose from a consensus meeting in June 2008 of specialists from different clinical and basic science fields. Dystonia is a movement disorder in which involuntary sustained or intermittent muscle contractions cause twisting and repetitive movements, abnormal postures, or both. Chorea is an ongoing random-appearing sequence of one or more discrete involuntary movements or movement fragments. Athetosis is a slow, continuous, involuntary writhing movement that prevents maintenance of a stable posture. Myoclonus is a sequence of repeated, often nonrhythmic, brief shock-like jerks due to sudden involuntary contraction or relaxation of one or more muscles. Tremor is a rhythmic back-and-forth or oscillating involuntary movement about a joint axis. Tics are repeated, individually recognizable, intermittent movements or movement fragments that are almost always briefly suppressible and are usually associated with awareness of an urge to perform the movement. Stereotypies are repetitive, simple movements that can be voluntarily suppressed. We provide recommended techniques for clinical examination and suggestions for differentiating between the different types of hyperkinetic movements, noting that there may be overlap between conditions. These definitions and the diagnostic recommendations are intended to be reliable and useful for clinical practice, communication between clinicians and researchers, and for the design of quantitative tests that will guide and assess the outcome of future clinical trials.

Alcohol, cocaine, and brain stimulation-reward in C57Bl6/J and DBA2/J mice.

BACKGROUND: Pleasure and reward are critical features of alcohol drinking that are difficult to measure in animal studies. Intracranial self-stimulation (ICSS) is a behavioral method for studying the effects of drugs directly on the neural circuitry that underlies brain reward. These experiments had 2 objectives: first, to establish the effects of alcohol on ICSS responding in the C57Bl6/J (C57) and DBA2/J (DBA) mouse strains; and second, to compare these effects to those of the psychostimulant cocaine. METHODS: Male C57 and DBA mice were implanted with unipolar stimulating electrodes in the lateral hypothalamus and conditioned to spin a wheel for reinforcement by the delivery of rewarding electrical stimulation (i.e., brain stimulation-reward or BSR). Using the curve-shift method, the BSR threshold (theta(0)) was determined immediately before and after oral gavage with alcohol (0.3, 0.6, 1.0, 1.7 g/kg) or water. Blood alcohol concentration (BAC) was measured to determine the influence of alcohol metabolism on BSR threshold. Separately, mice were administered cocaine (1.0, 3.0, 10.0, 30.0 mg/kg) or saline intraperitoneally. RESULTS: In C57 mice, the 0.6 g/kg dose of alcohol lowered BSR thresholds by about 20%, during the rising (up to 40 mg/dl), but not falling, phase of BAC. When given to the DBA mice, alcohol lowered BSR thresholds over the entire dose range; the largest reduction was by about 50%. Cocaine lowered BSR thresholds in both strains. However, cocaine was more potent in DBA mice than in C57 mice as revealed by a leftward shift in the cocaine dose-response curve. For both alcohol and cocaine, effects on BSR threshold were dissociable from effects on operant response rates. CONCLUSIONS: In C57 and DBA mice, reductions in BSR threshold reflect the ability of alcohol to potentiate the neural mechanisms of brain reward. The DBA mice are more sensitive to the reward-potentiating effects of both alcohol and cocaine, suggesting that there are mouse strain differences in the neural mechanisms of brain reward that can be measured with the ICSS technique.

Augmentation of cocaine-sensitized dopamine release in the nucleus accumbens of adult mice following prenatal cocaine exposure.

Behavioral changes in adult mice after prenatal exposure to cocaine have been identified. Mice exposed to cocaine in utero (40 or 20 mg/kg/day) and controls were given a sensitizing cocaine regimen (15 mg/kg every other day x 7 doses), withdrawn for 21 days, and challenged with 15 mg/kg cocaine. In vivo microdialysis for dopamine (DA), serotonin, and their metabolites in awake behaving mice on the first, seventh and challenge doses showed increased cocaine-stimulated DA release in the nucleus accumbens, which was significantly enhanced after prenatal cocaine exposure. This effect was not due to fetal malnutrition or changes in the total tissue DA content. Early developmental cocaine exposure may alter adaptation of brain reward systems to chronic psychostimulant exposure in adulthood.

Prenatal exposure to cocaine alters the development of conditioned place-preference to cocaine in adult mice.

As addiction is increasingly formulated as a developmental disorder, identifying how early developmental exposures influence later responses to drugs of abuse is important to our understanding of substance abuse neurobiology. We have previously identified behavioral changes in adult mice following gestational exposure to cocaine that differ when assessed with methods employing contingent and non-contingent drug administration. We sought to clarify this distinction using a Pavlovian behavioral measure, conditioned place-preference. Adult mice exposed to cocaine in utero (40 or 20 mg/kg/day), vehicle and pair-fed controls were place-conditioned to either cocaine (5 mg/kg or 20 mg/kg, i.p.) or saline injections. The development of conditioned place-preference to cocaine was impaired in mice exposed to cocaine in utero, and was abolished by fetal malnutrition. A context-specific place-aversion to vehicle but not cocaine injection was observed in prenatally cocaine-exposed mice. Locomotor behavior did not differ among prenatal treatment groups. We conclude that early developmental exposure to cocaine may diminish the subsequent rewarding effects of cocaine in adulthood measured with classical conditioning techniques, and that this is not due to changes in locomotor behavior. Sensitivity to acute stress is also altered by prenatal cocaine exposure, consistent with earlier findings in this model.

Oligonucleotide targeting to alveolar macrophages by mannose receptor-mediated endocytosis.

Antisense oligonucleotides (ONs) have proven useful for selective inhibition of gene expression. However, their effective use is limited by inefficient cellular uptake and lack of cellular targeting. In this paper, we report a drug targeting system which utilizes mannose receptor-mediated endocytosis to enhance cellular uptake of ONs in alveolar macrophages (AMs). The system employs a molecular complex consisting of partially substituted mannosylated poly(L-lysine) (MPL), electrostatically linked to a 5' fluorescently labeled ON. Upon recognition by the macrophage mannose receptors, the MPL was internalized by the receptor-mediated pathway, co-transporting the ON. Our results indicate that the AMs treated with the MPL:ON complex exhibited a significant increase in ON uptake (up to 17-fold) over free ON-treated controls. Effective ON uptake was shown to require the recognition of the mannose moiety since unmodified polylysine was much less effective in promoting ON uptake. Specific internalization of the ON:MPL complex by the mannose receptor pathway was verified by competitive inhibition using mannosylated albumin. Under this condition, the ON complex uptake was inhibited. The requirement of mannose receptors for complex uptake was further demonstrated using a macrophage cell line, J774.1, which expresses a low level of mannose receptors. When treated with the complex, these cells showed no susceptibility to ON uptake, thus suggesting the targeting ability of the carrier system to the AMs. Following cellular internalization, the ON complex appeared largely accumulated in endocytic vesicles. Enhanced endosomal exit of the ON was achieved using a fusogenic peptide derived from the amino terminal sequence of influenza virus hemagglutinin HA2. Cytotoxicity studies showed that at the concentrations effectively enhancing ON uptake, both MPL and the fusogenic peptide caused no toxic effects to the cells, thereby suggesting their potential safety and utilization in vivo.

Synthesis and secretion of mucous glycoprotein by the gill of Mytilus edulis. I. Histochemical and chromatographic analysis of [14C]glucosamine bioincorporation.

The ability of the isolated gill epithelium of Mytilus edulis to incorporate [14C]glucosamine as a precursor in the biosynthesis and secretion of mucous glycoproteins was investigated. Localization of mucous cells in the gill filament was achieved using histochemical staining techniques. Mucus cells containing neutral and acidic mucins were found in the lateral region, whereas mucus cells containing primarily neutral or sulfated mucins were found in the abfrontal region. Autoradiographic results showed that in both regions, the mucous cells were rich in content of the incorporated radiolabel. The secreted glycoproteins containing the incorporated radiolabel were analyzed by column chromatography using Bio-Gel P-2 and P-6. Two populations of the glycoproteins differing in molecular size were isolated. Upon alkaline reductive borohydride cleavage of the O-glycosidic linkages of the high molecular weight protein, about 70% of the radiolabel and 85% of the carbohydrate content were removed from the protein. The alkaline borohydride cleavage resulted in the formation of at least six oligosaccharide chains of various lengths of sugar units. Gas chromatographic analysis of the carbohydrate composition shows that the glycoproteins contain N-acetylglucosamine, N-acetylgalactosamine, and galactose, fucose, and mannose as the neutral monosaccharides. The above results indicate that the isolated gill epithelium of M. edulis is capable of incorporating [14C]glucosamine in the synthesis of secretable mucin-type glycoproteins.

A pharmacogenetic determinant of mu-opioid receptor antagonist effects on alcohol reward and consumption: evidence from humanized mice.

BACKGROUND: It has been proposed that therapeutic responses to naltrexone in alcoholism are moderated by variation at the mu-opioid receptor gene locus (OPRM1). This remains controversial because human results vary and no prospectively genotyped studies have been reported. We generated humanized mice carrying the respective human OPRM1 A118G alleles. Here, we used this model system to examine the role of OPRM1 A118G variation for opioid antagonist effects on alcohol responses. METHODS: Effects of naltrexone on alcohol reward were examined using intracranial self-stimulation. Effects of naltrexone or nalmefene on alcohol intake were examined in continuous access home cage two-bottle free-choice drinking and operant alcohol self-administration paradigms. RESULTS: Alcohol lowered brain stimulation reward thresholds in 118GG mice in a manner characteristic of rewarding drugs, and this effect was blocked by naltrexone. Brain stimulation reward thresholds were unchanged by alcohol or naltrexone in 118AA mice. In the home cage, increased alcohol intake emerged in 118GG mice with increasing alcohol concentrations and was 33% higher at 17% alcohol. At this concentration, naltrexone selectively suppressed alcohol intake in 118GG animals to a level virtually identical to that of 118AA mice. No effect of naltrexone was found in the latter group. Similarly, both naltrexone and nalmefene were more effective in suppressing operant alcohol self-administration in 118GG mice. CONCLUSIONS: In a model that allows close experimental control, OPRM1 A118G variation robustly moderates effects of opioid antagonism on alcohol reward and consumption. These findings strongly support a personalized medicine approach to alcoholism treatment that takes into account OPRM1 genotype.

Receptor Reserve Moderates Mesolimbic Responses to Opioids in a Humanized Mouse Model of the OPRM1 A118G Polymorphism.

The OPRM1 A118G polymorphism is the most widely studied µ-opioid receptor (MOR) variant. Although its involvement in acute alcohol effects is well characterized, less is known about the extent to which it alters responses to opioids. Prior work has shown that both electrophysiological and analgesic responses to morphine but not to fentanyl are moderated by OPRM1 A118G variation, but the mechanism behind this dissociation is not known. Here we found that humanized mice carrying the 118GG allele (h/mOPRM1-118GG) were less sensitive than h/mOPRM1-118AA littermates to the rewarding effects of morphine and hydrocodone but not those of other opioids measured with intracranial self-stimulation. Reduced morphine reward in 118GG mice was associated with decreased dopamine release in the nucleus accumbens and reduced effects on GABA release in the ventral tegmental area that were not due to changes in drug potency or efficacy in vitro or receptor-binding affinity. Fewer MOR-binding sites were observed in h/mOPRM1-118GG mice, and pharmacological reduction of MOR availability unmasked genotypic differences in fentanyl sensitivity. These findings suggest that the OPRM1 A118G polymorphism decreases sensitivity to low-potency agonists by decreasing receptor reserve without significantly altering receptor function.

A New DREADD Facilitates the Multiplexed Chemogenetic Interrogation of Behavior.

DREADDs are chemogenetic tools widely used to remotely control cellular signaling, neuronal activity, and behavior. Here we used a structure-based approach to develop a new Gi-coupled DREADD using the kappa-opioid receptor as a template (KORD) that is activated by the pharmacologically inert ligand salvinorin B (SALB). Activation of virally expressed KORD in several neuronal contexts robustly attenuated neuronal activity and modified behaviors. Additionally, co-expression of the KORD and the Gq-coupled M3-DREADD within the same neuronal population facilitated the sequential and bidirectional remote control of behavior. The availability of DREADDs activated by different ligands provides enhanced opportunities for investigating diverse physiological systems using multiplexed chemogenetic actuators.

Cocaine and SKF-82958 potentiate brain stimulation reward in Swiss-Webster mice.

RATIONALE: The dopamine D(1)-like receptor agonist SKF-82958 reportedly blocks reinstatement of cocaine-seeking behavior in rats and non-human primates. It is not known if SKF-82958 reduces drug-seeking behaviors in animals exposed previously to cocaine by causing reward-like effects or withdrawal-like aversive effects. OBJECTIVES: Intracranial self-stimulation (ICSS) studies were conducted to determine if SKF-82958 has reward-like or withdrawal-like effects in mice exposed previously to cocaine, or under the influence of cocaine at the time of testing. METHODS: Swiss-Webster mice with lateral hypothalamic stimulating electrodes were trained to self-administer rewarding brain stimulation. The mice were tested in a "curve-shift" variant of the ICSS procedure after intraperitoneal administration of cocaine alone (2.5-20 mg/kg), SKF-82958 alone (0.03-0.3 mg/kg), or a mixture of both drugs (SKF 0.03 mg/kg + 2.5 or 5.0 mg/kg cocaine). Each treatment was given twice. RESULTS: Cocaine and SKF-82958 each caused dose-dependent decreases in brain stimulation reward thresholds that were largest immediately after administration. A dose of SKF-82958 with no reward-related effects of its own potentiated the reward-related effects of low doses of cocaine. Repeated administration did not cause progressive changes in the ability of any treatment to decrease thresholds. CONCLUSIONS: Cocaine and SKF-82958 each potentiate the rewarding effects of lateral hypothalamic brain stimulation in Swiss-Webster mice, implying that these drugs have rewarding effects of their own. The reward-facilitating effects of low doses of cocaine and SKF-82958 are additive (or synergistic). These data suggest that SKF-82958 may decrease cocaine-seeking behavior by mechanisms related to reward rather than aversion.

Case series: spectrum of neuroleptic-induced movement disorders and extrapyramidal side effects in childhood-onset schizophrenia.

OBJECTIVE: Neuroleptic-treated pediatric patients with childhood-onset schizophrenia (COS) are at risk for developing extrapyramidal side effects and involuntary movement disorders. A preliminary examination of the incidence of withdrawal dyskinesias (WD), tardive dyskinesia (TD), and extrapyramidal side effects in these patients is presented. METHOD: Thirty-four COS patients (mean age +/- SD, 14.2 +/- 2.1 years) were examined for TD using the Abnormal Involuntary Movements Scale and for extrapyramidal side effects using the Simpson-Angus Neurologic Rating Scale, after a 14- to 28-day drug-free period (n = 33), at week 6 of treatment and 2 to 4 years after completion of the study (n = 14). The mean (+/-SD) number of months of prior neuroleptic exposure for the group was 22.4 (15.0) months. RESULTS: Seventeen (50%) of 34 patients were noted to have either WD or TD at some point during their participation in the studies. The majority of patients experienced WD that were mainly in the orofacial region, transient in nature, and diminished with haloperidol and clozapine. Patients with TD/WD had greater levels of premorbid impairment (p = .02), increased severity of positive symptoms of schizophrenia (p < .01), and a trend toward more months of neuroleptic exposure (p = .10, one-tailed). CONCLUSIONS: A high proportion of COS patients were found to have TD/WD. The majority of these abnormal movements were not severe and generally improved over time. TD/WD in COS appears to be associated with greater premorbid impairment, severity of illness, and duration of neuroleptic exposure. J. Am. Acad.

Childhood-onset schizophrenia: an open-label study of olanzapine in adolescents.

OBJECTIVE: Olanzapine, a potent 5-HT2a/2c, dopamine D1D2D4 antagonist with anticholinergic activity, has a profile of known receptor affinity similar to that of clozapine. This pilot study examined the efficacy of olanzapine for treatment-refractory childhood-onset schizophrenia in eight patients who had received 8-week open-label trials. For comparison, data are included from 15 patients who had received 6-week open-label clozapine trials using identical rating instruments (largely by the same raters) in the same treatment setting. METHOD: Twenty-three children and adolescents with an onset of DSM-III-R schizophrenia by age 12 for whom at least two different typical neuroleptics had been ineffective participated in the two separate studies. Some of the patients were intolerant of clozapine, although it had been effective (n = 4). Patients receiving olanzapine were evaluated over 8 weeks with the Brief Psychiatric Rating Scale (BPRS), the Scale for the Assessment of Positive Symptoms, the Scale for the Assessment of Negative Symptoms, and the Clinical Global Impressions Scale for Improvement. RESULTS: For the eight patients who received olanzapine trials, at week 8 there was a 17% improvement in the BPRS total score, a 27% improvement in the Scale for the Assessment of Negative Symptoms, and a 1% improvement in the Scale for the Assessment of Positive Symptoms, relative to "ideal" admission status on typical neuroleptics. In contrast, the magnitude of the effect sizes for each of the clinical ratings was larger at week 6 of the previous clozapine trial than for an 8-week olanzapine trial, relative to admission status on typical neuroleptics. For the four children who had received both clozapine and olanzapine, BPRS total scores were significantly lower at week 6 of clozapine treatment compared with week 6 of olanzapine treatment (p = .03). CONCLUSION: These data provide preliminary evidence for the efficacy of olanzapine for some children and adolescents with treatment-refractory schizophrenia, but they also suggest the need for a more rigorous double-blind comparison of these two atypical antipsychotics.

Neuropathological consequences of prenatal cocaine exposure in the mouse.

We have developed an animal model in Swiss Webster mice to identify mechanisms by which prenatal exposure to cocaine results in persistent alterations in brain structure and function. Clinical data suggests that children who demonstrate the largest impairments in prenatal brain growth, which are positively correlated with the highest level of prenatal cocaine exposure, are more likely to demonstrate selective impairment in postnatal brain growth, as well as postnatal impairments in motor function, attention and language skills. We conducted neuroanatomic studies to identify the postnatal evolution of structural changes in the primary somatosensory (SI) cortex of the developing mouse brain following prenatal exposure to cocaine. Our previous work, and that of others, provides evidence that many of the processes underlying corticogenesis are disrupted by gestational exposure of the developing mouse brain to cocaine, and that from the earliest phases of corticogenesis that there is an imprecision in the development of cortical lamination. We performed morphometric comparisons between the brains of animals prenatally exposed to varying amounts of cocaine with vehicle and malnutrition controls on postnatal (P) days P9 and P50. We found that on P50, but not P9, the relative number of cortical neurons in S1 is significantly less in cocaine exposed animals as compared with controls. The significant decrease in the number of cells in cocaine exposed animals on P50 is evident as a decreased density of cells restricted to the infragranular compartment (layers V and VI). Those changes are not seen in malnourished animals. Taken together our findings support the conclusion that cocaine-induced alterations in SI cortical cytoarchitectonics are in part a consequence of altered postnatal survival of infragranular cortical neurons, which are lost during the interval between P9 and P50. Determining whether a similar process is evident in a subset of humans following in utero cocaine exposure is a high priority for future clinical brain imaging studies, because analogous structural changes could impact the brain function and behavioral repertoire of infants and children following significant prenatal exposures.