The motion of the contact line at the oil/water interface caused by chemical reactions is well known as a typical example of artificial active matter in the field of nonlinear science. When water (containing trimethylstearylammonium chloride) and nitrobenzene (containing iodide anion) phases are in contact, the regulated traveling-wave patterns appear along the inner wall of the glass container. In this study, we demonstrate a new dynamical mode of the contact line, an up-and-down motion, which becomes dominant with the decrease in the size of a glass tube, and the probability of occurrence is extremely high when the diameter of the glass tube is below 1 mm. A physicochemical model of the contact line motion that incorporates the spatiotemporal variation of the surfactant concentration on a glass surface is proposed, and its effect on the wettability of oil/water phases on the walls of the glass tubes is studied. The present model can reproduce the mode bifurcation of the dynamical motion depending on the inner diameter of the glass tubes.

Neurotransporters are high-affinity transport proteins located in the plasma membrane of both presynaptic nerve and glial cells that mediate the removal of neurotransmitters from the synaptic cleft or represent intracellular transport systems that concentrate neurotransmitters in synaptic vesicles. They comprise three subgroups, Na+/Cl-- or Na+/K+-dependent cell surface transporters and H+-dependent transporters associated with synaptic vesicles. The new insights into neurotransporter diversity provide the means for novel approaches of studying neurotransmitter uptake processes at the molecular level, such as substrate translocation and antagonist binding as well as regulation of gene expression, of intracellular trafficking, and of posttranslational modification. Moreover, modeling neurotransporter-related disorders and therapeutic strategies in genetically engineered animals are now feasible research strategies. Through an improved understanding of the modulation of neurotransporter function in the brain, it may be possible to identify the molecular factors underlying the etiopathogenesis and pathophysiology of neurodegenerative disorders. Due to their specificity for distinct neuronal systems, neurotransporters and their genes are potential targets for novel therapeutic strategies.

Dysfunctions in serotonergic pathways may underlie several psychiatric disorders. The reuptake of serotonin (5-HT) from synaptic terminals is mediated by a specific transporter (5-HTT). Genetic variation in the gene coding for the 5-HTT protein might be involved in the predisposition to psychiatric disorders. A systematic screening of the whole coding sequence of the 5-HTT gene in mood disorder (MD) and obsessive-compulsive disorder (OCD) patients, as well as in healthy controls, using PCR and denaturing gradient gel electrophoresis (DGGE) revealed the presence of two mutations. The first was in intron 4, and the second was a C-->A transversion leading to an amino-acid exchange (Leu-->Met) in position 255 of the deduced protein sequence. No further occurrence of this substitution was found in an extended sample of patients and controls. Therefore, structural modifications of the 5-HTT gene do not seem to play either a major or minor role in the genetic predisposition to MD or OCD.

In der Entwicklung neuro- und psychobiologischer Forschung konzentrierte sich das Interesse zunächst auf die an der Synapse freigesetzten Neurotransmitter sowie auf ihre Rezeptoren. Aber auch dem zugehörigen Abbau oder der Wiederaufnahme in das Neuron durch Neurotransmitter-Wieder-ufnahmemechanismen (Neurotransporter) kommt eine entscheidende Rolle bei der Regulation des Neurotransmittergleichgewichts an der Synapse zu. Dieses Zusammenspiel stellt sich dabei als Kreislauf dar: Nach Synthese des Neurotransmitters und Speicherung in den synaptischen Vesikeln des präsynaptischen Neurons erfolgt auf die Depolarisation als auslösenden Reiz die Entleerung in den synaptischen Spalt. Dort bindet der Transmitter an entprechende post- und präsynaptischen Rezeptoren. Die präzise Beendigung der Wirkung wird über Abbauenzyme, z. B. beim Azetylcholin, sowie über Rücktransport in die präsynaptische Nervenendigung oder benachbarte Glia, z. B. bei den biogenen Aminen Serotonin (5-HT), Noradrenalin (NA) und Dopamin (DA) geregelt (Abb. 1). Daran wiederum können sich Abbauvorgänge im präsynaptischen Neuron, z. B. mittels der Monoaminoxidase (MAO), oder eine erneute Aufnahme in die Speichervesikel über den Reserpin-sensitiven vesikulären Monoamin-Transporter (VMT) anschließen. Somit stehen die Neurotransmitter für die erneute Freisetzung bereit. Der aktive Rücktransport von Neurotransmittern wird dabei über lonengradienten getrieben, im Falle des Transports der biogenen Amine in das präsynaptische Neuron über einen Symport mit Natrium-Ionen, dessen elektrochemischer Gradient über die Natrium-/Kalium-ATPase aufrecht erhalten wird, oft aber auch in Abhängigkeit von Kalium- oder Chlorid-Ionen (Abb. 2).

Clinical evidence for a dominant mode of inheritance and anticipation in periodic catatonia, a distinct subtype of schizophrenia, indicates that genes with triplet repeat expansions or other unstable repetitive elements affecting gene expression may be involved in the etiology of this disorder. Because patients affected with dentatorubral-pallidoluysian atrophy (DRPLA) may present with “schizophrenic” symptoms, we have investigated the DRPLA (B 37 CAG repeat) locus on chromosome 12 in 41 patients with periodic catatonia. The B 37 CAG repeat locus was highly polymorphic but all alleles in both the patient and control group had repeat sizes within the normal range. We conclude that variation at the DRPLA locus is unlikely to be associated with periodic catatonia. The evidence for dominant inheritance and anticipation as well as the high prevalence of human brain genes containing trinucleotide repeats justifies further screening for triplet repeat expansions in periodic catatonia.

The gene encoding the human serotonin transporter (5-HTT) has been isolated and characterized. The human 5-HTT gene is composed of 14 exons spanning ∼ 31 kb. The sequence of all exons including adjacent intronic sequences and a tandem repeat DNA polymorphism (VNTR) has been determined and deposited in the EMBL/GenBank data base with the accession numbers X76753 to X76762. The characterization of 5-HTT gene will aid to advance molecular pharmacologic studies of 5-HT uptake regulation and facilitate investigations of its role in psychiatric disorders.