Neuroprotection by adenosine in the brain: From A1 receptor activation to A2A receptor blockade

Adenosine is a neuromodulator that operates via the most abundant inhibitory adenosine A1 receptors (A1Rs) and the less abundant, but widespread, facilitatory A2ARs. It is commonly assumed that A1Rs play a key role in neuroprotection since they decrease glutamate release and hyperpolarize neurons. In fact, A1R activation at the onset of neuronal injury attenuates brain damage, whereas its blockade exacerbates damage in adult animals. However, there is a down-regulation of central A1Rs in chronic noxious situations. In contrast, A2ARs are up-regulated in noxious brain conditions and their blockade confers robust brain neuroprotection in adult animals. The brain neuroprotective effect of A2AR antagonists is maintained in chronic noxious brain conditions without observable peripheral effects, thus justifying the interest of A2AR antagonists as novel protective agents in neurodegenerative diseases such as Parkinson’s and Alzheimer’s disease, ischemic brain damage and epilepsy. The greater interest of A2AR blockade compared to A1R activation does not mean that A1R activation is irrelevant for a neuroprotective strategy. In fact, it is proposed that coupling A2AR antagonists with strategies aimed at bursting the levels of extracellular adenosine (by inhibiting adenosine kinase) to activate A1Rs might constitute the more robust brain neuroprotective strategy based on the adenosine neuromodulatory system. This strategy should be useful in adult animals and especially in the elderly (where brain pathologies are prevalent) but is not valid for fetus or newborns where the impact of adenosine receptors on brain damage is different

„Zaubern“ lernen – Welche pädagogischen Inhalte umfassen sogenannte Trainerausbildungen?

Obwohl davon auszugehen ist, dass Lehrende in der betrieblichen Weiterbildung wichtig für den Trainingserfolg sind, ist die Qualifizierung von Trainerinnen und Trainern in Deutschland nicht geregelt. Häufig dient eine so-genannte Trainerausbildung als pädagogischer Professionalitätsnachweis. Die Studie erfasst die Inhalte dieser Ausbildungen und deren Häufigkeiten. Hierfür wurden Programmbeschreibungen von 47 Anbietern mithilfe der qualitativen Inhaltsanalyse ausgewertet. Das induktiv entwickelte Kategoriensystem umfasst 56 Kategorien auf drei Hierarchieebenen. Die Ausbildungen zielen vor allem auf die praktische Befähigung zur Gestaltung von Seminaren ab. Häufig sind außerdem Inhalte, die sich auf Gruppendynamik und Kommunikationsprozesse beziehen. Theoretisches und empirisches Wissen spielen hingegen eine untergeordnete Rolle

Substrate-induced magnetic ordering and switching of iron porphyrin molecules

To realize molecular spintronic devices, it is important to externally control the magnetization of a molecular magnet. One class of materials particularly promising as building blocks for molecular electronic devices is the paramagnetic porphyrin molecule in contact with a metallic substrate. Here, we study the structural orientation and the magnetic coupling of in-situ-sublimated Fe porphyrin molecules on ferromagnetic Ni and Co films on Cu(100). Our studies involve X-ray absorption spectroscopy and X-ray magnetic circular dichroism experiments. In a combined experimental and computational study we demonstrate that owing to an indirect, superexchange interaction between Fe atoms in the molecules and atoms in the substrate (Co or Ni) the paramagnetic molecules can be made to order ferromagnetically. The Fe magnetic moment can be rotated along directions in plane as well as out of plane by a magnetization reversal of the substrate, thereby opening up an avenue for spin-dependent molecular electronics