0428 Taiep Rats Had Normal Levels of Orexin Neurons in the Lateral Hypothalamus But Their Cataplexy Attacks are Sensible to Specific Orexin B Agonist

Introduction

Narcolepsy is characterized by sleep fragmentation, sleep paralysis, hypnagogic hallucinations and cataplexy. The cataplexy is a sudden loss of muscle tone triggered by emotions in humans, as well as in animal models. It is stablished that most of the patients had a significant decrease of orexin neurons in the lateral hypothalamus. Taiep rats had a mutation in tubulin TUBB4A and suffer immobility episodes (IE′s) that had a desynchronized activity in the cortex associated with theta rhythm in the hippocampus similar to narcolepsy patients. The aim of this study was to analyze the effects of central administration of an orexin B agonist and determination by immunohistochemistry of the number of orexin neurons on adult male taiep rats.

Methods

We used 14 male taiep rats of 9 months of age. The subjects (Ss) lived 3-4 in acrylic cages with water and food pellets ad libitum, under a 12:12 light-dark cycle (lights on at 0700), whit-controlled temperature and humidity in the recording room. All Ss were implanted to record EEG, EMG and EOG to characterize immobility episodes (IE′s) in a control 8 h recording and after i.c.v. administration of [Ala 11, D-Leu 15]-orexin B with 1, 3 and 10 nmol/1 μL. We measured the number, mean duration and latency to the first IE′s.

Results

The administration of [Ala 11, D-Leu 15]-orexin B significantly reduced the number of IE′s (P<0.01), from 4.28 ± 1.5 IE′s to just 0.25 ± 0.17 with 10 nmol/1 μL dose, but did not change the amount of awakening, slow wave or rapid eye movement sleep. Importantly, the number or orexins neurons were similar between taiep and Sprague-Dawley rats.

Conclusion

The myelin mutant taiep rats is a model of narcolepsy with cataplexy with normal number of orexin neurons in the lateral hypothalamus. Additionally, a specific orexin B agonist reduced IE′s without any effect the sleep pattern. This could be useful for the design of new treatments.

Support

CONACYT grants 243333 and 243247 to CC and JRE, respectively. Grants from VIEP-BUAP 2019 and CA in Neuroendocrinología BUAP-CA-288.

Clcn7F318L/+ as a new mouse model of Albers-Schönberg disease

Dominant negative mutations in CLCN7, which encodes a homodimeric chloride channel needed for matrix acidification by osteoclasts, cause Albers-Schönberg disease (also known as autosomal dominant osteopetrosis type 2). More than 25 different CLCN7 mutations have been identified in patients affected with Albers-Schönberg disease, but only one mutation (Clcn7^G213R) has been introduced in mice to create an animal model of this disease. Here we describe a mouse with a different osteopetrosis-causing mutation (Clcn7^F318L). Compared to Clcn7^+/+ mice, 12-week-old Clcn7^F318L/+ mice have significantly increased trabecular bone volume, consistent with Clcn7^F318L acting as a dominant negative mutation. Clcn7^F318L/F318L and Clcn7^F318L/G213R mice die by 1month of age and resemble Clcn7 knockout mice, which indicate that p.F318L mutant protein is non-functional and p.F318L and p.G213R mutant proteins do not complement one another. Since it has been reported that treatment with interferon gamma (IFN-G) improves bone properties in Clcn7^G213R/+ mice, we treated Clcn7^F318L/+ mice with IFN-G and observed a decrease in osteoclast number and mineral apposition rate, but no overall improvement in bone properties. Our results suggest that the benefits of IFN-G therapy in patients with Albers-Schönberg disease may be mutation-specific.

Comparison of nanostructured titania matrices obtained by carbon template and sol-gel methods for controlled release of fluoxetine

Two types of titania matrix were investigated as a support for the prolonged drug delivery of the antidepressant fluoxetine. Sample MT was synthesized using carbon template and consisted of titania microtubes on which then fluoxetine was adsorbed. Sample SG was synthesized by the sol-gel method when the drug was added during the reaction. The morphology of the powder surfaces was found to be different: nanotubes versus almost spherical particles with much larger surface area of SG and smaller pores. The relative degrees of hydroxyl coverage of the surface were studied by FTIR-spectroscopy and were found to be much larger for the sol-gel complex. Theoretical modeling was applied to consider possible interactions between the drug and the matrices. The liberation of the drug was proved to be faster from complex MT and was attributed to weaker drug-matrix interactions in combination with larger pore size.

Syntheses of quinazoline-2,4-dione alkaloids and analogues from Mexican Zanthoxylum species

Quinazolinone and quinazolinedione derivatives are of considerable interest due to their wide array of pharmacological properties. In this paper we report the synthesis of ten quinazolinediones. The previous isolation of two of these compounds, namely 1-methyl-3-(2'-phenylethyl)-1H,3H-quinazoline-2,4-dione and 1-methyl-3-[2'-(4'- methoxyphenyl)ethyl]-lH,3H-quinazoline-2,4-dione, from the seed husks of Mexican Zanthoxylum species has been reported.

Method for analysis of polymer-supported organic compounds using mass spectrometry direct insertion

A new approach on the use of mass spectrometry direct-insertion and a quadrupole detector for analysis of organic compounds supported in solid phase has been developed. This is a simple and efficient method based on cleavage due to the thermal-instability of the benzylic group of most commercial resins. The cleavage of supported compounds takes place in the spectrometer as a consequence of the high temperature in the instrument's chamber. These compounds are detected using a similar fragmentation pattern and a molecular ion corresponding to the same compound obtained by traditional synthesis. Polymer degradation fragments do not interfere with the spectrum interpretation, because only a few peaks and low intensities are detected. We report here the identification of different types of compounds supported in Merrifield resin, such as bis-o-aminobenzamides and simple aromatic and aliphatic compounds, using this new approach.