PI3-kinase cascade has a differential role in acquisition and extinction of conditioned fear memory in juvenile and adult rats.

The basolateral amygdala (BLA), medial prefrontal cortex (mPFC) circuit, plays a crucial role in acquisition and extinction of fear memory. Extinction of aversive memories is mediated, at least in part, by the phosphoinositide-3 kinase (PI3K)/Akt pathway in adult rats. There is recent interest in the neural mechanisms that mediate fear and extinction in juvenile animals and whether these mechanisms are distinctive from those in adult animals. In the present study, we examined (1) changes in phosphorylation of Akt in the BLA and mPFC after fear conditioning and extinction in juvenile and adult rats and (2) the effect of BLA and mPFC localized inhibition of the PI3K following acquisition and extinction of contextual fear memory. Our results show that Akt phosphorylation is increased following acquisition of contextual fear learning in the BLA but not in the mPFC in adult and juvenile rats. Extinction learning was not associated with changes in Akt phosphorylation. Although there were no differences in the pattern of phosphorylation of Akt either in adult or juvenile rats, microinjection of the PI3K inhibitor, LY294002, into the BLA or mPFC elicited differential effects on fear memory acquisition and extinction, depending on the site and timing of the microinjection, as well as on the age of the animal. These results suggest that PI3K/Akt has a differential role in formation, retrieval, and extinction of contextual fear memory in juvenile and adult animals, and point to developmental differences between adult and juvenile rats in mechanisms of extinction.

Genetic dissection of an amygdala microcircuit that gates conditioned fear.

The role of different amygdala nuclei (neuroanatomical subdivisions) in processing Pavlovian conditioned fear has been studied extensively, but the function of the heterogeneous neuronal subtypes within these nuclei remains poorly understood. Here we use molecular genetic approaches to map the functional connectivity of a subpopulation of GABA-containing neurons, located in the lateral subdivision of the central amygdala (CEl), which express protein kinase C-δ (PKC-δ). Channelrhodopsin-2-assisted circuit mapping in amygdala slices and cell-specific viral tracing indicate that PKC-δ(+) neurons inhibit output neurons in the medial central amygdala (CEm), and also make reciprocal inhibitory synapses with PKC-δ(-) neurons in CEl. Electrical silencing of PKC-δ(+) neurons in vivo suggests that they correspond to physiologically identified units that are inhibited by the conditioned stimulus, called CEl(off) units. This correspondence, together with behavioural data, defines an inhibitory microcircuit in CEl that gates CEm output to control the level of conditioned freezing.

Neuroprotective mechanism of ischemic postconditioning in mice: a possible relationship between protein kinase C and nitric oxide pathways.

BACKGROUND: The present study was conducted to pharmacologically investigate the role of protein kinase C (PKC) pathway in neuroprotective mechanism of ischemic postconditioning (iPoCo) and determine the influence of nitric oxide (NO) signaling in PKC-mediated effects. MATERIALS AND METHODS: Bilateral carotid artery occlusion of 12 min followed by reperfusion for 24 h was used to produce ischemia and reperfusion (I/R)-induced cerebral injury in male Swiss mice. Memory was assessed using Morris water maze test. Degree of motor incoordination was evaluated using inclined beam-walk test, rota-rod test, and lateral push test. Cerebral infarct size was measured using triphenyltetrazolium chloride staining. Brain acetylcholinesterase activity, thiobarbituric acid reactive species, nitrite/nitrate, and reduced glutathione levels were also estimated. RESULTS: Bilateral carotid artery occlusion followed by reperfusion produced significant rise in cerebral infarct size, acetylcholinesterase activity, and thiobarbituric acid reactive species levels along with the fall in nitrite/nitrate and glutathione levels. A significant impairment of memory and motor coordination was also noted. iPoCo consisting of three episodes of 10 s carotid artery occlusion and reperfusion significantly attenuated infarct size, memory impairment, motor incoordination, and altered biochemicals. iPoCo-induced neuroprotective effects were significantly abolished by chelerythrine (a nonselective PKC inhibitor). L-Arginine, an NO precursor significantly attenuated I/R-induced injury and mimicked the neuroprotective effect of postconditioning. Furthermore, this protective effect of L-arginine on I/R injury and iPoCo was abolished when it was coadministered with chelerythrine. CONCLUSIONS: It may be concluded that neuroprotective mechanism of iPoCo involves PKC mediated pathway with NO signaling as an essential step.

Constitutive activation of Ca2+/calmodulin-dependent protein kinase II during development impairs central cholinergic transmission in a circuit underlying escape behavior in Drosophila.

Development of neural circuitry relies on precise matching between correct synaptic partners and appropriate synaptic strength tuning. Adaptive developmental adjustments may emerge from activity and calcium-dependent mechanisms. Calcium/calmodulin-dependent protein kinase II (CaMKII) has been associated with developmental synaptic plasticity, but its varied roles in different synapses and developmental stages make mechanistic generalizations difficult. In contrast, we focused on synaptic development roles of CaMKII in a defined sensory-motor circuit. Thus, different forms of CaMKII were expressed with UAS-Gal4 in distinct components of the giant fiber system, the escape circuit of Drosophila, consisting of photoreceptors, interneurons, motoneurons, and muscles. The results demonstrate that the constitutively active CaMKII-T287D impairs development of cholinergic synapses in giant fiber dendrites and thoracic motoneurons, preventing light-induced escape behavior. The locus of the defects is postsynaptic as demonstrated by selective expression of transgenes in distinct components of the circuit. Furthermore, defects among these cholinergic synapses varied in severity, while the glutamatergic neuromuscular junctions appeared unaffected, demonstrating differential effects of CaMKII misregulation on distinct synapses of the same circuit. Limiting transgene expression to adult circuits had no effects, supporting the role of misregulated kinase activity in the development of the system rather than in acutely mediating escape responses. Overexpression of wild-type transgenes did not affect circuit development and function, suggesting but not proving that the CaMKII-T287D effects are not due to ectopic expression. Therefore, regulated CaMKII autophosphorylation appears essential in central synapse development, and particular cholinergic synapses are affected differentially, although they operate via the same nicotinic receptor.

Deletion of ecto-5'-nucleotidase (CD73) reveals direct action potential-dependent adenosine release.

Purinergic signaling is a highly complex system of extracellular communication involved in many physiological and pathological functions in the mammalian brain. Its complexity stems from the multitude of purine receptor subtypes and endogenous purine receptor ligands (including ATP, ADP, UTP, UDP, and adenosine). Potentially all of these ligands could be directly released, and some could also arise from extracellular metabolism. A widely held consensus is that, except under pathological conditions, extracellular adenosine arises only from ectoATPase-mediated metabolism of previously released ATP. Here, we have used mice that lack the CD73 gene (encoding ecto-5'-nucleotidase that converts AMP to adenosine) to test whether action potential-dependent adenosine release in the cerebellum depends on prior ATP release. Surprisingly, we have uncovered two parallel pathways of adenosine release: one that is indirect via glutamate receptor-dependent release of ATP and a second of equal amplitude that has no dependence on prior release of ATP and thus represents the direct release of adenosine. This component of adenosine release is blocked by bafilomycin and modulated by mGlu4 receptor activation, strongly supporting adenosine release by exocytosis from parallel fibers. Our findings are a major step in understanding the mechanisms of adenosine release and are likely to have implications for all aspects of physiology where adenosine plays a key modulatory role.

A stochastic signaling network mediates the probabilistic induction of cerebellar long-term depression.

Many cellular processes involve a small number of molecules and undergo stochastic fluctuations in their levels of activity. Cerebellar long-term depression (LTD) is a form of synaptic plasticity expressed as a reduction in the number of synaptic AMPA receptors (AMPARs) in Purkinje cells. We developed a stochastic model of the LTD signaling network, including a PKC-ERK-cPLA(2) positive feedback loop and mechanisms of AMPAR trafficking, and tuned the model to replicate calcium uncaging experiments. The signaling network activity in single synapses switches between two discrete stable states (LTD and non-LTD) in a probabilistic manner. The stochasticity of the signaling network causes threshold dithering and allows at the macroscopic level for many different and stable mean magnitudes of depression. The probability of LTD occurrence in a single spine is only modulated by the concentration and duration of the signal used to trigger it, and inputs with the same magnitude can give rise to two different responses; there is no threshold for the input signal. The stochasticity is intrinsic to the signaling network and not mostly dependent on noise in the calcium input signal, as has been suggested previously. The activities of the ultrasensitive ERK and of cPLA(2) undergo strong stochastic fluctuations. Conversely, PKC, which acts as a noise filter, is more constantly activated. Systematic variation of the biochemical population size demonstrates that threshold dithering and the absence of spontaneous LTD depend critically on the number of molecules in a spine, indicating constraints on spine size in Purkinje cells.

Central adaptation to odorants depends on PI3K levels in local interneurons of the antennal lobe.

We have previously shown that driving PI3K levels up or down leads to increases or reductions in the number of synapses, respectively. Using these tools to assay their behavioral effects in Drosophila melanogaster, we showed that a loss of synapses in two sets of local interneurons, GH298 and krasavietz, leads to olfaction changes toward attraction or repulsion, while the simultaneous manipulation of both sets of neurons restored normal olfactory indexes. We show here that olfactory central adaptation also requires the equilibrated changes in both sets of local interneurons. The same genetic manipulations directed to projection (GH146) or mushroom body (201Y, MB247) neurons did not affect adaptation. Also, we show that the equilibrium is a requirement for the glomerulus-specific size changes which are a morphological signature of central adaptation. Since the two sets of local neurons are mostly, although not exclusively, inhibitory (GH298) and excitatory (krasavietz), we interpret that the normal phenomena of sensory perception, measured as an olfactory index, and central adaptation rely on an inhibition/excitation ratio.

Inhibition of calcium/calmodulin-dependent protein kinase kinase ß and calcium/calmodulin-dependent protein kinase IV is detrimental in cerebral ischemia.

BACKGROUND AND PURPOSE: Elevation of intracellular calcium was traditionally thought to be detrimental in stroke pathology. However, clinical trials testing treatments that block calcium signaling have failed to improve outcomes in ischemic stroke. Emerging data suggest that calcium may also trigger endogenous protective pathways after stroke. Calcium/calmodulin-dependent protein kinase kinase (CaMKK) is a major kinase activated by rising intracellular calcium. Compelling evidence has suggested that CaMKK and its downstream kinase CaMK IV are critical in neuronal survival when cells are under ischemic stress. We examined the functional role of CaMKK/CaMK IV signaling in stroke. METHODS: We used a middle cerebral artery occlusion model in mice. RESULTS: Our data demonstrated that pharmacological and genetic inhibition of CaMKK aggravated stroke injury. Additionally, deletion of CaMKK ß, one of the 2 CaMKK isoforms, reduced CaMK IV activation, and CaMK IV deletion in mice worsened stroke outcome. Finally, CaMKK ß or CaMK IV knockout mice had exacerbated blood-brain barrier disruption evidenced by increased hemorrhagic transformation and activation of matrix metalloproteinase. We observed transcriptional inactivation including reduced levels of histone deacetylase 4 phosphorylation in mice with CaMKK ß or CaMK IV deletion after stroke. CONCLUSIONS: Our data have established that the CaMKK/CaMK IV pathway is a key endogenous protective mechanism in ischemia. Our results suggest that this pathway serves as an important regulator of blood-brain barrier integrity and transcriptional activation of neuroprotective molecules in stroke.

Hypothalamic mTOR pathway mediates thyroid hormone-induced hyperphagia in hyperthyroidism.

Hyperthyroidism is characterized in rats by increased energy expenditure and marked hyperphagia. Alterations of thermogenesis linked to hyperthyroidism are associated with dysregulation of hypothalamic AMPK and fatty acid metabolism; however, the central mechanisms mediating hyperthyroidism-induced hyperphagia remain largely unclear. Here, we demonstrate that hyperthyroid rats exhibit marked up-regulation of the hypothalamic mammalian target of rapamycin (mTOR) signalling pathway associated with increased mRNA levels of agouti-related protein (AgRP) and neuropeptide Y (NPY), and decreased mRNA levels of pro-opiomelanocortin (POMC) in the arcuate nucleus of the hypothalamus (ARC), an area where mTOR co-localizes with thyroid hormone receptor-α (TRα). Central administration of thyroid hormone (T3) or genetic activation of thyroid hormone signalling in the ARC recapitulated hyperthyroidism effects on feeding and the mTOR pathway. In turn, central inhibition of mTOR signalling with rapamycin in hyperthyroid rats reversed hyperphagia and normalized the expression of ARC-derived neuropeptides, resulting in substantial body weight loss. The data indicate that in the hyperthyroid state, increased feeding is associated with thyroid hormone-induced up-regulation of mTOR signalling. Furthermore, our findings that different neuronal modulations influence food intake and energy expenditure in hyperthyroidism pave the way for a more rational design of specific and selective therapeutic compounds aimed at reversing the metabolic consequences of this disease.

Induced pluripotent stem cell lines from Huntington's disease mice undergo neuronal differentiation while showing alterations in the lysosomal pathway.

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by an excessive expansion of a CAG trinucleotide repeat in the gene encoding the protein huntingtin, resulting in an elongated stretch of glutamines near the N-terminus of the protein. Here we report the derivation of a collection of 11 induced pluripotent stem (iPS) cell lines generated through somatic reprogramming of fibroblasts obtained from the R6/2 transgenic HD mouse line. We show that CAG expansion has no effect on reprogramming efficiency, cell proliferation rate, brain-derived neurotrophic factor level, or neurogenic potential. However, genes involved in the cholesterol biosynthesis pathway, which is altered in HD, are also affected in HD-iPS cell lines. Furthermore, we found a lysosomal gene upregulation and an increase in lysosome number in HD-iPS cell lines. These observations suggest that iPS cells from HD mice replicate some but not all of the molecular phenotypes typically observed in the disease; additionally, they do not manifest increased cell death propensity either under self-renewal or differentiated conditions. More studies will be necessary to transform a revolutionary technology into a powerful platform for drug screening approaches.

Lateral regions of the rodent striatum reveal elevated glutamate decarboxylase 1 mRNA expression in medium-sized projection neurons.

The GABA-synthesizing enzymes glutamate decarboxylase (GAD)1 and GAD2 are universally contained in GABAergic neurons in the central nervous system of the mouse and rat. The two isoforms are almost identically expressed throughout the brain and spinal cord. By using in situ hybridization, we found that the mouse lateral striatum concentrates medium-sized projection neurons with high-level expression of GAD1, but not of GAD2, mRNA. This was confirmed with several types of riboprobe, including those directed to the 5'-noncoding, 3'-noncoding and coding regions. Immunohistochemical localization of GAD1 also revealed predominant localization of the enzyme in the same striatal region. The lateral region of the mouse striatum, harboring such neurons, is ovoid in shape and extends between interaural +4.8 and +2.8, and at lateral 2.8 and dorsoventral 2.0. This intriguing region corresponds to the area that receives afferent inputs from the primary motor and sensory cortex that are presumably related to mouth and forelimb representations. The lateral striatum is included in the basal ganglia-thalamocortical loop, and is most vulnerable to various noxious stimuli in the neurodegeneration processes involving the basal ganglia. We have confirmed elevated expression of GAD1 mRNA, but not of GAD2 mRNA, also in the rat lateral striatum. Image analysis favored the view that the regional increase is caused by elevated cellular expression, and that the greatest number of medium-sized spiny neurons were positive for GAD1 mRNA. The GAD1 mRNA distribution in the mouse lateral striatum partially resembled those of GPR155 and cannabinoid receptor type 1 mRNAs, suggesting functional cooperation in some neurons.

Current therapeutic strategies to mitigate the eNOS dysfunction in ischaemic stroke.

Impairment of endothelial nitric oxide synthase (eNOS) activity is implicated in the pathogenesis of endothelial dysfunction in many diseases including ischaemic stroke. The modulation of eNOS during and/or following ischaemic injury often represents a futile compensatory mechanism due to a significant decrease in nitric oxide (NO) bioavailability coupled with dramatic increases in the levels of reactive oxygen species that further neutralise NO. However, applications of a number of therapeutic agents alone or in combination have been shown to augment eNOS activity under a variety of pathological conditions by potentiating the expression and/or activity of Akt/eNOS/NO pathway components. The list of these therapeutic agents include NO donors, statins, angiotensin-converting enzyme inhibitors, calcium channel blockers, phosphodiesterase-3 inhibitors, aspirin, dipyridamole and ellagic acid. While most of these compounds exhibit anti-platelet properties and are able to up-regulate eNOS expression in endothelial cells and platelets, others suppress eNOS uncoupling and tetrahydrobiopterin (an eNOS stabiliser) oxidation. As the number of therapeutic molecules that modulate the expression and activity of eNOS increases, further detailed research is required to reveal their mode of action in preventing and/or reversing the endothelial dysfunction.

The kynurenine system and immunoregulation.

There is developing interest in the role of the kynurenines in the immune function. A considerable amount of evidence has accumulated as concerns interactions between the kynurenine pathway, cytokines and the nervous system. Indoleamine 2,3-dioxygenase (IDO) occupies a key position connecting the immune system and the kynurenine pathway. There are evidences of the immunosuppressive effect of IDO. Following the interferon (IFN)-mediated activation of antigen presenting cells, the induction of IDO and the kynurenine system exerts a counter-regulating effect, maintaining the homeostasis. Inhibition of T cell functions, activation of the regulatory T cells, and the inhibition of Natural Killer cells are among the important factors in the immunosuppressive effects of IDO and kynurenines. There is a close connection between cytokines (IFN-α, IFN-γ, TNF-α, TGF-ß, IL-4 and IL-23) and the kynurenine system, and an imbalance in the TH1/TH2 cytokine profile may possibly lead to neurologic or psychiatric disorders. As the tryptophan metabolic pathway is activated by pro-inflammatory stimuli, the anti-inflammatory effect of kynurenic acid provides a further feedback mechanism in modulating the immune responses.

Role of glucocorticoids in tuning hindbrain stress integration.

The nucleus of the solitary tract (NTS) is a critical integrative site for coordination of autonomic and endocrine stress responses. Stress-excitatory signals from the NTS are communicated by both catecholaminergic [norepinephrine (NE), epinephrine (E)] and noncatecholaminergic [e.g., glucagon-like peptide-1 (GLP-1)] neurons. Recent studies suggest that outputs of the NE/E and GLP-1 neurons of the NTS are selectively engaged during acute stress. This study was designed to test mechanisms of chronic stress integration in the paraventricular nucleus, focusing on the role of glucocorticoids. Our data indicate that chronic variable stress (CVS) causes downregulation of preproglucagon (GLP-1 precursor) mRNA in the NTS and reduction of GLP-1 innervation to the paraventricular nucleus of the hypothalamus. Glucocorticoids were necessary for preproglucagon (PPG) reduction in CVS animals and were sufficient to lower PPG mRNA in otherwise unstressed animals. The data are consistent with a glucocorticoid-mediated withdrawal of GLP-1 in key stress circuits. In contrast, expression of tyrosine hydroxylase mRNA, the rate-limiting enzyme in catecholamine synthesis, was increased by stress in a glucocorticoid-independent manner. These suggest differential roles of ascending catecholamine and GLP-1 systems in chronic stress, with withdrawal of GLP-1 involved in stress adaptation and enhanced NE/E capacity responsible for facilitation of responses to novel stress experiences.

N-acetylglucosamine 6-O-sulfotransferase-1-deficient mice show better functional recovery after spinal cord injury.

Neurons in the adult CNS do not spontaneously regenerate after injuries. The glycosaminoglycan keratan sulfate is induced after spinal cord injury, but its biological significance is not well understood. Here we investigated the role of keratan sulfate in functional recovery after spinal cord injury, using mice deficient in N-acetylglucosamine 6-O-sulfotransferase-1 that lack 5D4-reactive keratan sulfate in the CNS. We made contusion injuries at the 10th thoracic level. Expressions of N-acetylglucosamine 6-O-sulfotransferase-1 and keratan sulfate were induced after injury in wild-type mice, but not in the deficient mice. The wild-type and deficient mice showed similar degrees of chondroitin sulfate induction and of CD11b-positive inflammatory cell recruitment. However, motor function recovery, as assessed by the footfall test, footprint test, and Basso mouse scale locomotor scoring, was significantly better in the deficient mice. Moreover, the deficient mice showed a restoration of neuromuscular system function below the lesion after electrical stimulation at the occipito-cervical area. In addition, axonal regrowth of both the corticospinal and raphespinal tracts was promoted in the deficient mice. In vitro assays using primary cerebellar granule neurons demonstrated that keratan sulfate proteoglycans were required for the proteoglycan-mediated inhibition of neurite outgrowth. These data collectively indicate that keratan sulfate expression is closely associated with functional disturbance after spinal cord injury. N-acetylglucosamine 6-O-sulfotransferase-1-deficient mice are a good model to investigate the roles of keratan sulfate in the CNS.

Activation of silent and weak synapses by cAMP-dependent protein kinase in cultured cerebellar granule neurons.

Presynaptic long term potentiation of synaptic transmission activates silent synapses and potentiates existing active synapses. We sought to visualise these two processes by studying the cAMP-dependent protein kinase (PKA) potentiation of presynaptic vesicle cycling in cultured cerebellar granule neurons.Using FM dyes to label the pool of recycling synaptic vesicles,we found that trains of electrical stimulation which do not potentiate already active synapses are sufficient to rapidly activate a discrete population comprising silent and very low activity synapses. Silent synapse activation required PKA activity and conversely, active synapses could be silenced by PKA inhibition. Surprisingly, the recycling pool of synaptic vesicles in recently activated synapses was larger than in already active synapses and equivalent to synapses treated with forskolin. Imaging of synaptic vesicle cycling and cytosolic Ca(2+) in individual nerve terminals confirmed that silent synapses have evoked Ca(2+) transients comparable to those of active synapses. Furthermore, across populations of active synapses, changes in Ca(2+) influx did not correlate with changes in the size of the pool of recycling synaptic vesicles. Finally, we found that stimulation of synapsin phosphorylation, but not RIM1α, by PKA was frequency dependent and long lasting. These data are consistent with the idea that PKA regulates synaptic vesicle recycling downstream of Ca(2+) influx and that this pathway is highly active in recently activated synapses.

Differential effects of DAAO on regional activation and functional connectivity in schizophrenia, bipolar disorder and controls.

Recent studies have identified DAAO as a probable susceptibility gene for schizophrenia and bipolar disorder. However, little is known about how this gene affects brain function to increase vulnerability to these disorders. We examined the impact of DAAO genotype (rs3918346) on brain function in patients with schizophrenia, patients with bipolar I disorder and healthy controls. We tested the hypothesis that a variation in DAAO genotype would be associated with altered prefrontal function and altered functional connectivity in schizophrenia and bipolar disorder. We used functional magnetic resonance imaging to measure brain responses during a verbal fluency task in a total of 121 subjects comprising 40 patients with schizophrenia, 33 patients with bipolar disorder and 48 healthy volunteers. We then used statistical parametric mapping (SPM) and psycho-physiological interaction (PPI) analyses to estimate the main effects of diagnostic group, the main effect of genotype, and their interaction on brain activation and on functional connectivity. Inferences were made at p<0.05, after correction for multiple comparisons across the whole brain. In the schizophrenia group relative to the control group, patients with one or two copies of the T allele showed lower deactivation in the left precuneus and greater activation in the right posterior cingulate gyrus than patients with two copies of the C allele. This diagnosis×genotype interaction was associated with differences in the functional connectivity of these two regions with other cortical and subcortical areas. In contrast, there were no significant effects of diagnosis or of genotype in comparisons involving bipolar patients. Our results suggest that genetic variation in DAAO has a significant impact on both regional activation and functional connectivity, and provide evidence for a diagnosis-dependent pattern of gene action.

Autophagy failure in Alzheimer's disease--locating the primary defect.

Autophagy, the major degradative pathway for organelles and long-lived proteins, is essential for the survival of neurons. Mounting evidence has implicated defective autophagy in the pathogenesis of several major neurodegenerative diseases, particularly Alzheimer's disease (AD). A continuum of abnormalities of the lysosomal system has been identified in neurons of the AD brain, including pathological endocytic pathway responses at the very earliest disease stage and a progressive disruption of autophagy leading to the massive buildup of incompletely digested substrates within dystrophic axons and dendrites. In this review, we examine research on autophagy in AD and evaluate evidence addressing the specific step or steps along the autophagy pathway that may be defective. Current evidence strongly points to disruption of substrate proteolysis within autolysosomes for the principal mechanism underlying autophagy failure in AD. In the most common form of familial early onset AD, mutant presenilin 1 disrupts autophagy directly by impeding lysosomal proteolysis while, in other forms of AD, autophagy impairments may involve different genetic or environmental factors. Attempts to restore more normal lysosomal proteolysis and autophagy efficiency in mouse models of AD pathology have yielded promising therapeutic effects on neuronal function and cognitive performance, demonstrating the relevance of autophagy failure to the pathogenesis of AD and the potential of autophagy modulation as a therapeutic strategy. This article is part of a Special Issue entitled "Autophagy and protein degradation in neurological diseases."

PDE10A and PDE10A-dependent cAMP catabolism are dysregulated oppositely in striatum and nucleus accumbens after lesion of midbrain dopamine neurons in rat: a key step in parkinsonism physiopathology.

Loss of dopamine neurons in experimental parkinsonism results in altered cyclic nucleotide cAMP and cGMP levels throughout the basal ganglia. Our objective was to examine whether expression of phosphodiesterase 10A (PDE10A), an isozyme presenting a unique distribution in basal ganglia, is altered after unilateral injection of 6-hydroxydopamine in the medial forebrain bundle, eliminating all midbrain dopaminergic neurons, such that cyclic nucleotide catabolism and steady state could be affected. Our study demonstrates that PDE10A mRNA levels were decreased in striatal neurons 10 weeks after 6-hydroxydopamine midbrain lesion. Such changes occurred in the striatum ipsilateral to lesion and were paralleled by decreased PDE10A protein levels and activity in striatal neurons and in striato-pallidal and striato-nigral projections. However, PDE10A protein and activity were increased while PDE10A mRNA was unchanged in the nucleus accumbens ipsilateral to the 6-hydroxydopamine midbrain lesion. Accordingly, cAMP levels were down-regulated in the nucleus accumbens, and up-regulated in the striatum ipsilateral to the lesion, but they were not significantly changed in substantia nigra and globus pallidus. Unlike cAMP, cGMP levels were decreased in all dopamine-deafferented regions. The opposite variations of cAMP steady state in striatum and nucleus accumbens are concordant and likely dependent, at least in part, on the down-regulation of PDE10A expression and activity in the former and its up-regulation in the latter. On the other hand, the down-regulation of cGMP steady state in the striato-nigral and striato-pallidal complex is not consistent with and is likely independent from the concomitant down-regulation of PDE10A. Therefore, dopamine loss inversely regulates PDE10A gene expression in the striatum and PDE10A post-transcription in the nucleus accumbens, therein differentially modulating PDE10A-dependent cAMP catabolism.

Neurogenetics and clinical evidence for the putative activation of the brain reward circuitry by a neuroadaptagen: proposing an addiction candidate gene panel map.

This document presents evidence supporting the role of the KB220/KB220Z neuroadaptagens consisting of amino-acid neurotransmitter precursors and enkephalinase-catecholamine-methyl-transferase (COMT) inhibition therapy called Neuroadaptagen Amino Acid Therapy (NAAT) in brain reward function. It is becoming increasingly clear that this novel formulation is the first neuroadaptagen known to activate the brain reward circuitry. Ongoing research repeatedly confirms the numerous clinical effects that ultimately result in significant benefits for victims having genetic antecedents for all addictive, compulsive and impulsive behaviors. These behaviors are correctly classified under the rubric of"Reward Deficiency Syndrome" (RDS). We are proposing a novel addiction candidate gene map. We present preliminary findings in the United States using qEGG and in China using Functional Magnetic Resonance Imaging (fMRI) regarding the effects of oral NAAT on the activation of brain reward circuitry in victims of SUD. In unpublished data utilizing an fMRI 2X2 design at resting state, NAAT in comparison to placebo shows activation of the caudate brain region and potentially a smoothing out of heroin-induced putamen (a site for emotionality) abnormal connectivity. Although awaiting final analysis, if confirmed by ongoing studies in China coupled with published qEEG results in America, showing an increase in alpha and low beta, NAAT may be shown to impact treatment outcomes.