Glutamate Receptor

N-methyl-d-aspartate receptors (NMDARs) are present at many excitatory glutamate synapses in the central nervous system and display unique properties that depend on their subunit composition. Biophysical, pharmacological and molecular methods have been used to determine the key features conferred by the various NMDAR subunits, and have helped to establish which NMDAR subtypes are present at particular synapses. Recent studies are

A prior study found that one ketamine-assisted psychotherapy session was significantly more effective than active placebo in promoting abstinence (Krupitsky et al. 2002). In this study of the efficacy of single versus repeated sessions of ketamine-assisted psychotherapy in promoting abstinence in people with heroin dependence, 59 detoxified inpatients with heroin dependence received a ketamineassisted psychotherapy (KPT) session prior to their discharge from an addiction treatment hospital, and were then randomized into two treatment groups. Participants in the first group received two addiction counseling sessions followed by two KPT sessions, with sessions scheduled on a monthly interval (multiple KPT group). Participants in the second group received two addiction counseling sessions on a monthly interval, but no additional ketamine therapy sessions (single KPT group). At one-year follow-up, survival analysis demonstrated a significantly higher rate of abstinence in the multiple KPT group. Thirteen out of 26 subjects (50%) in the multiple KPT group remained abstinent. compared to 6 out of 27 subjects (22.2%) in the single KPT group (p < 0.05). No differences between groups were found in depression, anxiety, craving for heroin, or their understanding of the meaning of their lives. It was concluded that three sessions of ketamine-assisted psychotherapy are more effective than a single session for the treatment of heroin addiction.

D-serine plays a key role in glutamatergic neurotransmission in mammalian brain as a co-agonist of N-methyl-D-aspartate receptors. The enzyme responsible for D-serine biosynthesis, serine racemase (SR), is therefore a promising target for treatment of neuropathologies related to glutamate receptor excitotoxicity, such as stroke or Alzheimer&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s disease. Much of the experimental work to date has been performed on mouse serine racemase, which shares a high level of sequence identity with its human ortholog. In this work, we report the synthesis of a human SR gene variant optimized for heterologous expression in Escherichia coli and describe the expression and purification of active recombinant human SR. This strategy may be of general interest to researchers wishing to express mammalian proteins in a bacterial system. Furthermore, we conduct a thorough analysis of the kinetics and inhibitor-sensitivity of the recombinant enzyme, and we provide the first direct comparison of human and mouse SR based on our kinetic data. The orthologs behave similarly overall and exhibit identical inhibition profiles, validating the use of mouse models in SR research.

Kainate receptors form a family of ionotropic glutamate receptors that appear to play a special role in the regulation of the activity of synaptic networks. This review first describes briefly the molecular and pharmacological properties of native and recombinant kainate receptors. It then attempts to outline the general principles that appear to govern the function of kainate receptors in the activity of synaptic networks under physiological conditions. It subsequently describes the way that kainate receptors are involved in synaptic integration, synaptic plasticity, the regulation of neurotransmitter release and the control of neuronal excitability, and the manner in which they might play an important role in synaptogenesis and synaptic maturation. These functions require the proper subcellular localization of kainate receptors in specific functional domains of the neuron, necessitating complex cellular and molecular trafficking events. We show that our comprehension of these mechanisms is just starting to emerge. Finally, this review presents evidence that implicates kainate receptors in pathophysiological conditions such as epilepsy, excitotoxicity and pain, and that shows that these receptors represent promising therapeutic targets.

All current drugs approved to treat schizophrenia appear to exert their antipsychotic effects through blocking the dopamine D2 receptor. Recent meta-analyses and comparative efficacy studies indicate marginal differences in efficacy of newer atypical antipsychotics and the older drugs, and little effects on negative and cognitive symptoms. This review integrates findings from postmortem, imaging, and drug-challenge studies to elucidate a corticolimbic &quot;pathologic circuit&quot; in schizophrenia that may be particularly relevant to the negative symptoms and cognitive impairments of schizophrenia. Potential sites for pharmacologic intervention targeting glutatatergic, GABAergic, and cholinergic neurotransmission to treat these symptoms of schizophrenia are discussed.