Spontaneous myogenic fasciculation associated with the lengthening of cardiac muscle in response to static preloading.

Force enhancement is one kind of myogenic spontaneous fasciculation in lengthening preload striated muscles. In cardiac muscle, the role of this biomechanical event is not well established. The physiological passive property is an essential part for maintaining normal diastole in the heart. In excessive preload heart, force enhancement relative erratic passive properties may cause muscle decompensating, implicate in the development of diastolic dysfunction. In this study, the force enhancement occurrence in mouse cardiac papillary muscle was evaluated by a microstepping stretch method. The intracellular Ca2+ redistribution during occurrence of force enhancement was monitored in real-time by a Flou-3 (2 mM) indicator. The force enhancement amplitude, the enhancement of the prolongation time, and the tension-time integral were analyzed by myography. The results indicated that the force enhancement occurred immediately after active stretching and was rapidly enhanced during sustained static stretch. The presence of the force and the increase in the amplitude synchronized with the acquisition and immediate transfer of Ca2+ to adjacent fibres. In highly preloaded fibres, the enhancement exceeded the maximum passive tension (from 4.49 ± 0.43 N/mm2 to 6.20 ± 0.51 N/mm2). The occurrence of force enhancement were unstable in each static stretch. The increased enhancement amplitude combined with the reduced prolongation time to induce a reduction in the tension-time integral. We concluded that intracellular Ca2+-synchronized force enhancement is one kind of interruption event in excessive preload cardiac muscle. During the cardiac muscle in its passive relaxation period, the occurrence of this interruption affected the rhythmic stability of the cardiac relaxation cycle.

Pharmacokinetic and pharmacodynamic analysis of ferulic acid-puerarin-astragaloside in combination with neuroprotective in cerebral ischemia/reperfusion injury in rats.

OBJECTIVE: To investigate the effects of the active ingredients combined therapy on inflammatory factors interleukin 1 beta (IL-1ß) and neuropeptide Y (NPY) based on pharmacodynamics in rats. METHODS: The animal model was built by transient middle cerebral artery occlusion (MCAO). The method for evaluating the concentrations of the FA-Pr-Al components in rat plasma was established by using HPLC and the expression levels of IL-1ß and NPY were determined by ELISA. A new mathematics method of the trend of percentage rate of change (PRC) was used to assess the correlation between pharmacokinetics (PK) and pharmacodynamics (PD). RESULTS: FA-Pr-Al in combination reduced neurological deficits, decreased infarct volume and inhibited the expression levels of IL-1ß and NPY (all P<0.05) compared with the model group. FA, Pr and Al all displayed two compartment open models in rats. Clockwise hysteresis loops were obtained by time-concentration-effect curves. IL-1ß and NPY level changes in the plasma followed an opposite trend to the plasma concentration tendency after Cmax was reached. Astragaloside's PRC value was significantly higher than those of FA and puerarin between 120 to 180 min. CONCLUSIONS: The pharmacokinetics of FA-Pr-Al in combination were closely related its pharmacodynamics in treating ischemia/reperfusion injury, and the components of FA-Pr-Al may have a synergistic pharmacological effect. Astragaloside may play a more pronounced role in regulating IL-1ßand NPY levels compared with puerarin or FA.

[Experiment study of tongfu huoxue decoction in the treatment of intracelebral hemorrhage].

OBJECTIVE: To investigate the effects of Tongfu Huoxue decoction on experimental intracelebral hemorrhage and the associated machenisms. METHOD: The cerebral hemorrhage model in rats was induced by local injection of type VII collagenase and they were randomly divided into four groups. The treated groups were treated with Naoxuekang and Tongfu Huoxue decoction. The control groups were only treated with water. The changes of neurological defect were observed. The content of brain water, MDA, NO and the activity of SOD were measured. RESULT: The cerebral hemorrhage rats showed hemiplegia, and the hemorrhage brains showed celebral edema, higher quotient of brain and content of brain water, suggesting the hemorrhage model was established successfully. After the treatment of Tongfu Huoxue decoction, the hemorrhage rats showed smaller hemorrhage volume, the brain tissue from the hemorrhage rats had lower MDA content and the quotient of brain, and also had higher activity of SOD and content of NO. CONCLUSION: Tongfu Huoxue decoction has treatment effects on cerebral hemorrhage.