Significantly increased lifespan and improved behavioral performances by rAAV gene delivery in adult mucopolysaccharidosis IIIB mice.

Mucopolysaccharidosis (MPS) IIIB is an inherited lysosomal storage disease, caused by the deficiency of alpha-N-acetylglucosaminidase (NaGlu), resulting in severe global neurological involvement with high mortality. One major hurdle in therapeutic development for MPS IIIB is the presence of the blood-brain barrier, which impedes the global central nervous system (CNS) delivery of therapeutic materials. In this study, we used a minimal invasive strategy, combining an intravenous (i.v.) and an intracisternal (i.c.) injection, following an i.v. infusion of mannitol, to complement the CNS delivery of adeno-associated viral (AAV) vector for treating MPS IIIB in young adult mice. This treatment resulted in a significantly prolonged lifespan of MPS IIIB mice (11.1-19.5 months), compared with that without treatment (7.9-11.3), and correlated with significantly improved behavioral performances, the restoration of functional NaGlu, and variable correction of lysosomal storage pathology in the CNS, as well as in different somatic tissues. This study demonstrated the great potential of combining i.v. and i.c. administration for improving rAAV CNS gene delivery and developing rAAV gene therapy for treating MPS IIIB in patients.

Assessment of NMDA receptor activation in vivo by Fos induction after challenge with the direct NMDA agonist (tetrazol-5-yl)glycine: effects of clozapine and haloperidol.

Induction of Fos protein by the potent and direct NMDA agonist (tetrazol-5-yl)glycine (TZG) was examined in mice. Effects of antipsychotic drugs were assessed on this in vivo index of NMDA receptor activation. TZG induced the expression of Fos in a neuroanatomically selective manner, with the hippocampal formation showing the most robust response. In mice genetically altered to express low levels of the NR1 subunit of the NMDA receptor, TZG-induced Fos was reduced markedly in comparison to the wild type controls. TZG-induced Fos was also blocked by the selective NMDA antagonist MK-801. Pretreatment of mice with clozapine (3 and 10 mg/kg) reduced TZG-induced Fos in the hippocampal formation but not in other brain regions. Haloperidol at a dose of 0.5 mg/kg did not antagonize TZG induced Fos in any region. Haloperidol at a dose of 1.0 mg/kg did attenuate the induction of Fos by TZG in the hippocampus but not in other brain regions. The relatively high dose (1 mg/kg) of haloperidol required to block effects of TZG suggests that this action may not be related to the D(2) dopamine receptor-blocking properties, since maximal D(2) receptor blockade was probably achieved by the 0.5 mg/kg dose of haloperidol. The antidepressant drug imipramine (10 or 20 mg/kg) did not antagonize TZG induced Fos in any brain region. The data suggest that clozapine can reduce excessive activation of NMDA receptors by TZG administration in vivo at doses relevant to the drugs' actions in rodent models of antipsychotic activity. Whether or not this action of clozapine contributes to its therapeutic properties will require further study.

Enhanced ultrasonic vocalization and Fos protein expression following ethanol withdrawal: effects of flumazenil.

RATIONALE: Administration of flumazenil, a benzodiazepine (BZD) antagonist, has therapeutic efficacy against some anxiogenic effects of ethanol withdrawal. This observation has led to the suggestion that anxiety associated with ethanol withdrawal is related to release in brain of an endogenous BZD inverse agonist. OBJECTIVE: The present studies further tested this hypothesis by assessing the effect of flumazenil on withdrawal-induced changes in a behavioral task and on the expression of the neuronal protein, Fos. METHODS: Male Sprague-Dawley rats were withdrawn from a chronic ethanol regimen and tested, with or without flumazenil pretreatment, for either ultrasonic vocalization in response to air puff or for the induction of Fos protein-like immunoreactivity (Fos-LI) in brain. In addition, flumazenil effects on Fos-LI were measured in a group of animals treated with the BZD inverse agonist DMCM (0.75 and 1.0 mg/kg). RESULTS: Flumazenil (5.0 mg/kg) significantly reduced the number of ultrasonic vocalizations observed following withdrawal from chronic ethanol. In contrast, flumazenil (5.0 mg/kg), given either 14 h before withdrawal from chronic ethanol, or during hours 3 and 5 following withdrawal, did not attenuate the effects of withdrawal on Fos-LI. Subsequent testing with DMCM confirmed that a benzodiazepine inverse agonist can induce Fos-LI in most of the same brain regions as observed following ethanol withdrawal, and that this change in Fos protein can be attenuated by pretreatment with flumazenil (5.0 mg/kg). CONCLUSIONS: Overall, these results demonstrate that specific behavioral indices of anxiety, but not measures of Fos-LI, support the contribution of an endogenous BZD inverse agonist in the ethanol withdrawal syndrome.

Metabolic mapping of the rat brain after subanesthetic doses of ketamine: potential relevance to schizophrenia.

Subanesthetic doses of ketamine have been shown to exacerbate symptoms in schizophrenia and to induce positive, negative, and cognitive schizophrenic-like symptoms in normal subjects. The present investigation sought to define brain regions affected by subanesthetic doses of ketamine, using high resolution autoradiographic analysis of 14C-2-deoxyglucose (2-DG) uptake and immunocytochemical staining for Fos-like immunoreactivity (Fos-LI). Both functional mapping approaches were used because distinct and complementary information is often obtained with these two mapping methods. Ketamine, at a subanesthetic dose of 35 mg/kg, substantially increased 2-DG uptake in certain limbic cortical regions, including medial prefrontal, ventrolateral orbital, cingulate, and retrosplenial cortices. In the hippocampal formation, the subanesthetic dose of ketamine induced prominent increases in 2-DG uptake in the dentate gyrus, CA-3 stratum radiatum, stratum lacunosum moleculare, and presubiculum. Increased 2-DG uptake in response to 35 mg/kg ketamine was also observed in select thalamic nuclei and basolateral amygdala. Ketamine induced Fos-LI in the same limbic cortical regions that exhibited increased 2-DG uptake in response to the subanesthetic dose of the drug. However, no Fos was induced in some brain regions that showed increased 2-DG uptake, such as the hippocampal formation, anterioventral thalamic nucleus, and basolateral amygdala. Conversely, ketamine induced Fos in the paraventricular nucleus of the hypothalamus and central amygdala, although no effect of the drug on 2-DG uptake was apparent in these regions. In contrast to the increase in 2-DG uptake observed in select brain regions after the subanesthetic dose, an anesthetic dose of ketamine (100 mg/kg) produced a global suppression of 2-DG uptake. By contrast, a robust induction of Fos-LI was observed after the anesthetic dose of ketamine that was neuroanatomically identical to that produced by the subanesthetic dose. Results of the present investigation show that anesthetic and subanesthetic doses of ketamine have pronounced effects on regional brain 2-DG uptake and induction of Fos-LI. The alterations in regional brain metabolism induced by the subanesthetic dose may be relevant to effects of ketamine to induce schizophrenic-like symptoms.