Antinociceptive and anticonvulsant effects of the monoterpene linalool oxide.

CONTEXT: Linalool oxide (OXL) (a monoterpene) is found in the essential oils of certain aromatic plants, or it is derived from linalool. The motivation for this work is the lack of psychopharmacological studies on this substance. OBJECTIVE: To evaluate OXL's acute toxicity, along with its anticonvulsant and antinociceptive activities in male Swiss mice. MATERIAL AND METHODS: OXL (50, 100 and 150 mg/kg, i.p.) was investigated for acute toxicity and in the Rota-rod test. Antinociceptive activity was evaluated by the acetic acid-induced writhing test, and by formalin testing. Anticonvulsant effects were demonstrated by testing for pentylenetetrazol (PTZ)-induced seizures and by Maximum Electroshock headset (MES) test. OXL was administered to the animals intraperitoneally 30 min before for pharmacological tests. RESULTS: OXL showed an LD50 of ∼721 (681-765) mg/kg. In the Rota-rod test, it was observed that OXL caused no damage to the animal's motor coordination. OXL significantly reduced (p < .001) the number of writhings. OXL also significantly decreased (p < .05, p < .01 or p < .001) paw-licking time in the two phases of the formalin test. OXL significantly reduced (p < .01 or p < .001) the duration of tonic seizures in the MES test, and at the dose 150 mg/kg, significantly increased (p < .01) the latency to first seizure in the PTZ test. CONCLUSION: The tested doses of OXL were safe, with no motor impairment, and show clear antinociceptive and anticonvulsant potential. Future investigations with this monoterpene may lead to the development of a new molecule with even higher potency and selectivity.

Anxiolytic-like effects of inhaled linalool oxide in experimental mouse anxiety models.

Linalool oxide is a monoterpene that is found in some species of aromatic plants. The effects of the inhalation of linalool oxide (0.65%, 1.25%, 2.5% and 5.0% w/w) in the elevated plus-maze and light/dark box tests as animal models of anxiety were investigated in adult male mice and compared with the effects of the reference anxiolytic diazepam (0.5 and 2.0 mg/kg), administered intraperitoneally. Additionally, the effects of inhaled linalool oxide were investigated in the rotarod test. Linalool oxide significantly increased the number of visits to the open arms of the elevated plus-maze and the amount of time spent there as well as the total number of entries. In the light/dark box test, inhalation of linalool oxide led to an increase in the time spent by the mice in the brightly-lit chamber and in the number of times the animal crossed from one compartment to another. Performance on the rotarod was unaffected. Thus, inhaled linalool oxide was found to have anxiolytic properties in both animal models, without causing any motor deficit. These results suggest that inhalation of linalool oxide may be a useful means of counteracting anxiety.

Atualizações e Perspectivas na Miastenia gravis / Updates and Perspectives on myasthenia gravis

Este estudo teve como objetivo uma buscabibliográfica sobre a Miastenia gravis (MG). Metodologia: Apesquisa bibliográfica foi realizada nas bases de dadoseletrônicos Pubmed, Science Direct, Scielo e Bireme dosúltimos dez anos, além de outros artigos que apresentavamextrema relevância histórica. Resultados: MG é uma doençaauto-imune caracterizada por fraqueza muscular, cujapatogenia está relacionada com a destruição da transmissãoneuromuscular por diferentes mecanismos, como diminuiçãodos receptores nicotínicos de acetilcolina, destruição dasproteínas envolvidas com a formação neuromuscular ou pelaatuação de anticorpos contra uma proteína quinase específicado músculo (MUSK). O tratamento atual da MG se baseia nautilização de inibidores da acetilcolinesterase, corticosteróides,timectomia, imunosupressores, imunoglobulinaintravenosa e plasmaferese. A identificação precoce da MGe de seus fatores precipitantes torna esta patologia maisacessível a novas modalidades de tratamento, comoanticorpos monoclonais, prolactina, tracolimus e crotamina.Conclusão: O melhor conhecimento acerca de seusmecanismos moleculares tem proporcionado o desenvolvimentode novas opções terapêuticas, necessárias paraamenizar crises severas, levando a um prognósticoadequado. Novas descobertas poderão contribuir para aqualidade de vida dos pacientes, ocasionando remissão dadoença e não apenas amenizando os seus sintomas...

This study aimed to a search the literature onmyasthenia gravis (MG). Methodology: Literature search wasconducted in the electronic databases PubMed, ScienceDirect, Scielo and Bireme, in the last ten years, and otherarticles that had extreme historical importance were alsoincluded. Results: MG is an autoimmune diseasecharacterized by muscle weakness, whose pathogenesisis related to the destruction of neuromuscular transmissionby different mechanisms, such as decreased nicotinicacetylcholine receptors, destruction of proteins involved inthe neuromuscular formation or the activity of antibodies ona specific muscle protein kinase (MUSK). The current treatmentof MG is based on the use of acetylcholinesterase inhibitors,corticosteroids, thymectomy, immunosuppressants,intravenous immunoglobulin and plasmapheresis. Earlyidentification of MG and its precipitating factors make thisdisease more accessible to new treatment modalities suchas monoclonal antibodies, prolactin, and tacrolimus crotamine.Conclusion: A better knowledge about molecular mechanismshas provided the development of new therapeutic optionsnecessary to alleviate severe crises, leading to a properprognosis. New findings may contribute to the quality of lifeof patients, resulting in remission of the disease and not justin relieving its symptoms...