Inhibitory effect of baicalein on mice tremor induced by oxotremorine and mechanisms

OBJECTIVE To investigate the anti-tremor effect and mechanism of baicalein on oxotremorine-induced muscle tremor in mice.METHODS The acute model of muscular tremor was induced by intraperitoneal injection of oxotremorine,and the latency,duration and frequency of muscle tremor in mice were measured immediately;the saliva of mice was measured to reflect the correlation between tremor and peripheral nerve function;the aim of this study was to determine the content of MDA and the activity of GSH-PX,and to investigate the anti-oxidation of mice with tremor model.The activity of acetylcholinesterase(AchE)and acetylcholine transferase(ChA T)can indirectly reflect the level of acetylcholine in the brain.The level of monoamine neurotransmitters in brain tissue was determined by high performance liquid chromatography(HPLC-ECD).RESULTS The animals in the model group appeared obvious tremoring,salivating and erecting and other symptoms.Compared to the model group,there was no obvious inhibitory effect on the administration of each dose.After 7,14,21 and 28 d of continuous administration,the latency,duration and tremor frequency of tremor mice were significantly shortened,the levels of acetylcholine were significantly decreased,the changes of DOPAC and DA neurotransmitters in the brain of model group were recovered,regulate the dynamic balance of acetylcholine and dopamine in the brain.CONCLUSION Long-term administration can improve the tremor behavior of mice,the mechanismmay be related to the regulation of neurotransmittersin brain.

A Decreased Expression and Functionality of Muscarinic Cholinergic Receptor in Acute Chagas Myocarditis

Background: Chagas disease is still a public health problem because of the remaining high prevalence, the expansion of the disease into developed countries and the re-emergences by oral transmission outbreaks. Chagas cardiomyopathy evolves as a consequence of an autonomic un-balance where the parasympathetic tone is undermined. Objective: To determine the functionality and expression of muscarinic cholinergic receptors in acute Chagas disease. Methodology: 62 male, 3-week-old Sprague Dawley rats were assayed;32 were infected with Trypanosoma cruzi trypo-mastigotes and 30 were healthy controls. Electrocardiographic studies were conducted in the absence or presence of direct muscarinic (oxotremorine and McN-A-343) or indirect agonists (phenylephrine) or antagonist (pirenzepine). Muscarinic M1 and M2 receptor expression was determined by radioligand [3H]-QNB binding assay and immunoblot. Results: Chagasic acute myocarditis was sustained by electrocardiographic signs and histopathological findings. Bradycardia induced by oxotremorine was significantly higher in healthy rats (HR) and the differences were enhanced by CsCl. In the absence of the agonist, CsCl induced a greater bradycardia in chagasic rats (ChR). In HR McN-A-343 induced tachycardia, however it induces bradycardia in the presence of a acetylcholinesterase inhibitor (neostigmine);no effects were observed in ChR. Pirenzepine induced a higher tachycardia in HR. Phenylephrine in the presence of pirenzepine induced a similar bradycardia in both groups, but recovery was faster in ChR. Muscarinic M1 and M2 receptor density was higher in HR. Conclusion: Muscarinic receptor expression and functionality are decreased in the acute Chagas disease that could impact the evolution and prognosis of the disease.