Prolactin concentrations in mouse milk during lactation

Summary Prolactin levels in mouse milk increased from the day of parturition to give a concentration of 230 ng/ml on days 2 and 3 of lactation. Thereafter, levels dropped to 140 ng/ml by day 6 and were maintained at this concentration until weaning.Acknowledgments. Mouse PRL and its antiserum was the generous gift of Y.N. Sinha (Scripps Clinic and Research Foundation, La Jolla, California). J.M.B. was in receipt of a Liverpool University Studentship.     

Dissociation between biochemical and ultrastructural effects of 6-hydroxydopamine in rat brain

Zusammenfassung Im Gehirn von Ratten bewirkt einmalige intraventrikuläre Injektion von 200 g 6-Hydroxydopamin nach 2 und 5 Tagen eine deutliche Verminderung von Noradrenalin und Dopamin, während 5-Hydroxytryptamin nur geringfügig herabgesetzt wird. Elektronenmikroskopisch sind keine strukturellen Veränderungen festzustellen. Zweimalige Injektion von 200 g 6-Hydroxydopamin führt dagegen zu schweren spezifischen Degenerationen im Bereich des Nucleus caudatus und Hypothalamus. Daraus wird geschlossen, dass niedrige Dosen 6-Hydroxydopamin die cerebralen Catecholamine vermindern können, ohne ultrastrukturelle Schädigungen des Gehirns zu verursachen.     

Electron microscopic localization of 5-hydroxydopamine,a ‘false’ adrenergic neurotransmitter,in the autonomic nerve endings of the rat pineal gland

Résumé La 5-hydroxydopamine (5-HO-DA), un «faux» neuro-transmetteur adrénergique, a été localisée dans les vésicules des terminaisons nerveuses sympathiques de la glande pinéale du rat, par examen au microscope électronique, après traitement des animaux par cette amine.     

Shape change reaction of platelets in protein-free medium: Ultramorphology

Summary Transmission and scanning electron microscopy indicate that rabbit platelets incubated in protein-poor medium retain their reactivity to shape change-inducing agents such as 5-hydroxytryptamine, adenosine-5-diphosphate and chlorpromazine. Such platelets may be used as models for drug-membrane interactions, e.g. in neuronal cells.     

Myosin domain evolution and the primary divergence of eukaryotes

Eukaryotic cells have two contrasting cytoskeletal and ciliary organizations. The simplest involves a single cilium-bearing centriole, nucleating a cone of individual microtubules (probably ancestral for unikonts: animals, fungi, Choanozoa and Amoebozoa). In contrast, bikonts (plants, chromists and all other protozoa) were ancestrally biciliate with a younger anterior cilium, converted every cell cycle into a dissimilar posterior cilium and multiple ciliary roots of microtubule bands. Here we show by comparative genomic analysis that this fundamental cellular dichotomy also involves different myosin molecular motors. We found 37 different protein domain combinations, often lineage-specific, and many previously unidentified. The sequence phylogeny and taxonomic distribution of myosin domain combinations identified five innovations that strongly support unikont monophyly and the primary bikont/unikont bifurcation. We conclude that the eukaryotic cenancestor (last common ancestor) had a cilium, mitochondria, pseudopodia, and myosins with three contrasting domain combinations and putative functions.