ABSTRACT
In the central nervous system, nitric oxide (NO), a free gas with multitudinous bioactivities, is mainly produced from the oxidation of L-arginine by neuronal nitric oxide synthase (nNOS). In the past 20 years, the studies in our group and other laboratories have suggested a significant involvement of nNOS in a variety of neurological and neuropsychiatric disorders. In particular, the interactions between the PDZ domain of nNOS and its adaptor proteins, including post-synaptic density 95, the carboxy-terminal PDZ ligand of nNOS, and the serotonin transporter, significantly influence the subcellular localization and functions of nNOS in the brain. The nNOS-mediated protein-protein interactions provide new attractive targets and guide the discovery of therapeutic drugs for neurological and neuropsychiatric disorders. Here, we summarize the work on the roles of nNOS and its association with multiple adaptor proteins on neurological and neuropsychiatric disorders.
ABSTRACT
The paraventricular nucleus of the thalamus (PVT), which serves as a hub, receives dense projections from the medial prefrontal cortex (mPFC) and projects to the lateral division of central amygdala (CeL). The infralimbic (IL) cortex plays a crucial role in encoding and recalling fear extinction memory. Here, we found that neurons in the PVT and IL were strongly activated during fear extinction retrieval. Silencing PVT neurons inhibited extinction retrieval at recent time point (24 h after extinction), while activating them promoted extinction retrieval at remote time point (7 d after extinction), suggesting a critical role of the PVT in extinction retrieval. In the mPFC-PVT circuit, projections from IL rather than prelimbic cortex to the PVT were dominant, and disrupting the IL-PVT projection suppressed extinction retrieval. Moreover, the axons of PVT neurons preferentially projected to the CeL. Silencing the PVT-CeL circuit also suppressed extinction retrieval. Together, our findings reveal a new neural circuit for fear extinction retrieval outside the classical IL-amygdala circuit.
ABSTRACT
<p><b>AIM</b>To search for novel compounds with potent nNOS inhibitory activity for the treatment of Alzheimer's disease.</p><p><b>METHODS</b>The target compounds were obtained by introducing benzenealkyl groups into the structure of isothioureas. nNOS inhibitory activity assays were conducted for the target compounds.</p><p><b>RESULTS</b>Sixteen benzenealkyl isothiourea compounds (I1-16) were synthesized by three different synthetic methods from benzylamine (1) or (substituted) phenethylamine (2). Compounds I1-6 were synthesized from 1 or 2 by reaction with benzoyl isothiocyanate to form the corresponding benzoylthioureas 3 or 4, followed by hydrolysis with 10% sodium hydroxide solution, then S-alkylation with methyl iodide or ethyl iodide. I7-14 were synthesized from 1 or 2 by reaction with methyl isothiocyanate to form the corresponding 1, 3-disubstituted thioureas 7 or 8 which were S-alkylated with methyl iodide or ethyl iodide. I15 and I16 were synthesized from 2 by reaction with dimethyl cyanodithioimidocarbonate. The structures of compounds I1-16 were confirmed by MS, IR, 1HNMR and elementary analysis. The results of preliminary pharmacological test showed that all compounds possessed nNOS inhibitory activity, among which compounds I8, I12 and I14 had good activity.</p><p><b>CONCLUSION</b>Compounds I8, I12 and I14 showed superior pharmacological profiles to the control compound S-methyl-N-(4-methoxyphenyl) isothiourea. The IC50 values of compounds I8, I12 and I14 inhibiting nNOS were 8.13 x 10(-7) mol.L-1, 1.74 x 10(-7) and 2.23 x 10(-7) mol.L-1 respectively, and it is worth further studying.</p>