Ethanol influence on insulin secretion from isolated rat islets

This study was done to delineate the role of alpha- and beta-adrenergic receptors and cyclic AMP in the mechanism of ethanol effects on insulin release from isolated islets. Rats were given an alpha-adrenergic blocker, phentolamine, or a beta-adrenergic blocker, propranolol. In addition, ethanol 1 g/kg was given intragastrically 1 h prior to sacrifice. Glucose mediated insulin release from isolated islets was enhanced by phentolamine and decreased by propranolol. Ethanol treatment inhibited glucose-induced insulin release from isolated islets of control rats as well as those given phentolamine and/or propranolol. Insulin release from isolated islets in response to dibutyryl-cyclic AMP was attenuated by ethanol. Theophylline enhanced glucose mediated insulin release from control islets but ethanol treatment produced a significant inhibition of insulin response. The data suggest that the site of action of the deleterious effects of ethanol on insulin release from isolated islets in rat does not involve adrenergic system and cyclic AMP.     

Metamorphic changes in the intracerebral neurosecretory pathways in the lemon-butterfly,Papilio demoleus L. (Lepidoptera)

Zusammenfassung Untersuchungen am Gehirn von Puppen und Imagines des SchmetterlingsPapilio demoleus zeigen, dass die Axone der neurosekretorischen Zellen der Pars intercerebralis in den Puppen vorerst nach innen vorwärts, dann nach rückwärts laufen, in Imagines aber direkt nach innen rückwärts ziehen. Die notwendigen ontogenetischen Lageänderungen der NSZ und ihrer Axone werden an einem Modell demonstriert.     

Effect of electric shock on serotonin (5 HT) content in different organs of rat

Summary 5 HT content of heart, brain, kidneys and liver in rats increases significantly after repeated exposure to electric shock followed by a trend of normalisation. These changes appear to be organ specific.     

Chloral hydrate induced haploidization inAspergillus nidulans

Summary This is the first report of induction of haploidization inAspergillus nidulans by chloral hydrate, which is an efficient polyploidizing agent for higher plants and a psychotropic drug for man. A new procedure has been described to isolate haploids from diploids with a very high frequency, as compared top-fluorophenylalanine, which is generally used for this purpose.     

Subunit arrangement and function in NMDA receptors

Excitatory neurotransmission mediated by NMDA (N-methyl-D-aspartate) receptors is fundamental to the physiology of the mammalian central nervous system. These receptors are heteromeric ion channels that for activation require binding of glycine and glutamate to the NR1 and NR2 subunits, respectively. NMDA receptor function is characterized by slow channel opening and deactivation, and the resulting influx of cations initiates signal transduction cascades that are crucial to higher functions including learning and memory. Here we report crystal structures of the ligand-binding core of NR2A with glutamate and that of the NR1-NR2A heterodimer with glutamate and glycine. The NR2A-glutamate complex defines the determinants of glutamate and NMDA recognition, and the NR1-NR2A heterodimer suggests a mechanism for ligand-induced ion channel opening. Analysis of the heterodimer interface, together with biochemical and electrophysiological experiments, confirms that the NR1-NR2A heterodimer is the functional unit in tetrameric NMDA receptors and that tyrosine 535 of NR1, located in the subunit interface, modulates the rate of ion channel deactivation.     

On the innervation of the prothoracic glands inPapilio demoleus L. (Lepidoptera)

Zusammenfassung Die Prothorakaldrüse der SchmetterlingsraupePapilio demoleus L. ist mit Sicherheit innerviert, wobei jede einzelne Drüsenzelle von Nervenendigungen umsponnen ist. Der Befund spricht für eine Aktivierung der Häutungsdrüse durch Neurosekret, das durch Nerven zugeführt wird.     

Raffinose inStomoxys calcitrans Linn. (diptera,cyclorrhaphpa: Muscidae)

Résumé La raffinose a été découverte pour la première fois dans l'insecteS. calcitrans, une mouche suceuse de sang. Le sucre est présent dans les ufs fraîchement pondus, dans les larves au troisième stage, dans les pupes blanches et dans les toutes jeunes mouches. On a aussi discuté le róle probable de ce sucre.