Alterations in the intrinsic properties of Purkinje cells (PCs) may contribute to the abnormal motor performance observed in ataxic rats. To investigate whether su ch changes in the intrinsic neuronal excitability could be attributed to the role of Ca2+ -activated K+ channels (KCa ), whole cell current clamp recordings were made from PCs in cerebellar slices of control and ataxic rats. 3-AP induced profound alterations in the intrinsic properties of PCs, as evidenced by a significant increase in both the membrane input resistance and the initial discharge frequency, along with the disruption of the firing regularity. In control PCs, the blockade of small conductance KCa channels by UCL1684 resulted in a significant increase in the membrane input resistance, action potential (AP) half-width, time to peak of the AP and initial discharge frequency. SK channel blockade also significantly decreased the neur onal discharge regularity, the peak amplitude of the AP, the amplitude of the after-hyperpolarization and the spike fr equency adaptation ratio. In contrast, in ataxic rats, both the firing regularity and the initial firing frequency were significantly increased by the blockade of SK channels. In conclusion, ataxia may arise from alterations in the functional contribution of SK channels, to the intrinsic properties of PCs., M. Kaffashian ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Recently, we have established a model of severe stepwise normovolemic hemodilution to a hematocrit of 10 % in rats employing three different colloidal volume replacement solutions (Voluven, Volulyte and Gelafundin) that are routinely used in clinical practice at present. We did not see severe dilutional acidosis as to be expected, but a decline in urinary pH. We here looked on further mechanisms of renal acid excretion during normovolemic hemodilution. Bicarbonate, which had been removed during normovolemic hemodilution, was calculated with the help of the Henderson-Hasselbalch equation. The urinary amount of ammonium as well as phosphate was determined in residual probes. The absolute amount of free protons in urine was obtained from the pH of the respective samples. The amount of protons generated during normovolemic hemodilution was approximately 0.6 mmol. During experimental time (5.5 h), distinct urinary ammonium excretion occurred (Voluven 0.52 mmol, Volulyte 0.39 mmol and Gelafundin 0.77 mmol). Proton excretion via the phosphate buffer constituted 0.04 mmol in every experimental group. Excretion of free protons was in the range of 10-6 mmol. The present data prove that the prompt rise in urinary ammonium excretion is also valid for acute metabolic acidosis originating from severe normovolemic hemodilution., J. K. Teloh, I. N. Waack, H. de Groot., and Obsahuje bibliografii
Studies have demonstrated that heat shock protein 70 (HSP70) plays an important role in the protection of stressed organisms. The development of strategies for enhancing HSPs expression may provide novel means of minimizing inflammatory lung conditions, such as acute lung injury. This study aimed to examine the effect of L-alanyl-L-glutamine (GLN) inhalation in enhancing pulmonary HSP72 (inducible HSP70) expression and attenuating lung damage in a model of acute lung injury induced by Lipopolysaccharide (LPS) inhalation. The experimental rats were randomly assigned to one of four experimental groups: (1) NS: saline inhalation; (2) NS-LPS: pretreatment by saline inhalation 12 h before LPS inhalation; (3) GLN: glutamine inhalation; (4) GLN-LPS: pretreatment by glutamine inhalation 12 h before LPS inhalation. The results show that GLN compared with saline administration, led to significant increase in lung HSP72 both in non LPS-treated rats and LPS-treated rats. In LPStreated rats, pretreatment by GLN inhalation produced less lung injury as evidenced by the decrease in lung injury score and dramatic decrease in lactate dehydrogenase (LDH) activity and polymorphonuclear leukocyte cell differentiation counts (PMN %) in the bronchoalveolar lavage fluid. The study indicates that prophylactic glutamine inhalation associated with the enhancement of HSP72 synthesis attenuates tissue damage in experimental lung injury., I.-C. Chuang, M.-S. Huang, L.-J. Huang, S.-H. Chou, T.-N. Tsai, Y.-C. Chen, R.-C. Yang., and Obsahuje bibliografii