Mice injected with tetanus toxin (TTx) showed an increase of 5-hydroxytryptamine (serotonin, 5-HT) levels in the central nervous system. The increment was not uniform throughout the central nervous system. Particularly significant were the 25% and 80% increases observed, respectively, in whole brain and spinal cord. The levels of dopamine and norepinephrine remained unchanged. The subsequent studies of 5-HT turnover revealed a synthesis rate in the tetanic animals that was almost double that of controls. The degradation rate of the amine as well as the levels of 5-hydroxyindolacetic acid were unaffected.
Background and Goal of Study: Cardiopulmonary bypass (CPB) is associated with a transition of pulsatile to non-pulsatile flow generated by the heart-lung machine. Non-pulsatile flow may deteriorate postoperative organ perfusion, but this has only scarcely been investigated on a microcirculatory level. We therefore hypothesized that non-pulsatile flow negatively influences microcirculatory perfusion in cardiac surgery, and this is prevented by pulsatile flow during ex tracorporeal circulation. Materials and Methods: Patients undergoing coronary artery bypass graf t (CABG) surgery were randomized into a non-pulsatile (n=15) or pulsatile (n=15) CPB group. Sublingual mucosal microvascular function was measured at preoperative, intraoperative and postoperative time points using sidestream dark field imaging and quantified as the level of perfused vessel density (PVD) and microvascular flow index (MFI). Microcirculation measurements were paralleled by hemodynamic and inflammatory parameter analysis. Results and Discussion: The observed reduction in PVD during aorta crossclamping was only restored in the pulsatile flow group and increased from 15.5±2.4 mm/mm 22 upon intensive care unit admission (P< 0.01). The median postoperative MFI was higher in the pulsatile group (2.8 (2.7-2.9)) than in the non-pulsatile group (2.5 (1.9-2.7); P< 0.05). There was no association of preserved microcirculatory vessel perfusion with inflammatory parameters. Pulsatile flow was associated with improved oxygen consumption from 71±14 to 85±14 ml/min/m 2 (P< 0.05) during aorta cross-clamping, which was not found for non-pulsatile flow. to 20.3±3.7 mm/mm Conclusion: Pulsatile CPB preserves microcirculatory perfusion throughout the early postoperative period. Improved oxygen consumption during pulsatile flow suggests decreased microcirculatory shunting during CPB, which may contribute to the observed preservation of microcirculatory function in the perioperative period.
Noradrenaline and taurine release from superfused rat cerebral cortex slices was stimulated by potassium ions, veratrine, ouabain and omission of sodium ions. Tetanus toxin enhanced only the ouabain-evoked calcium-dependent noradrenaline release and the ouabain-evoked calcium-independent taurine release. The uptake of both was marginally affected.
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