Veronica caespitosa Boiss.,V. bombycina Boiss.&Kotschy undV. thessalica Benth. gehören nicht in die SektionVeronicastrum Benth.

Zusammenfassung Die drei hochalpinen Polster-ZwergsträucherVeronica caespitosa Boiss.,V. bombycina Boiss. &Kotschy aus Kleinasien und dem Libanon sowieV. thessalica aus Nord-Griechenland und Albanien haben polytele Rumpfsynfloreszenzen (Troll, 1963), das heißt eine oder wenige laterale (axilläre) wenigblütige Trauben, deren Abstammungsachse in einen sterilen, wenige Blattpaare tragenden Gipfelsproß endet, der in der nächsten Vegetationsperiode monopodial weiterwächst und gegen die Spitze zu abermals laterale Trauben hervorbringt (Prolifikation). Diese Bauverhältnisse wurden bisher übersehen, da die blühenden Sprosse dieser hochalpinen Zwergstrauch-Polsterpflanzen gestaucht und dicht beblättert sind und der sterile Sproßgipfel von den Blütentrauben zur Seite gedrängt wird, so daß bei oberflächlicher Betrachtung der Eindruck eines endständigen köpfchenartig gedrängten Blütenstandes entsteht. Da die Stellung der Infloreszenzen für die GattungVeronica phylogenetisch und taxonomisch wichtig zu sein scheint, können die behandelten drei Arten nicht in der (akrobotryschen) SektionVeronicastrum verbleiben, die durch terminale Infloreszenzen charakterisiert ist, sondern müssen in die pleurobotrysche, durch ausschließlich laterale Infloreszenzen ausgezeichnete SektionenVeronica=(Chamaedrys) eingereiht werden.Ein fälschlich alsV. satureioides Vis. bestimmter Beleg in den Herbarien W und WU vonV. thessalica vom Gipfel des Berges Gjalica e Lumës (zirka 2470 m s. m.) in Nord-Albanien erweitert das bekannte Areal beträchtlich, denn die Art war bisher nur von dem etwa 250 Kilometer weiter südöstlich gelegenen Thessalischen Olymp in Griechenland bekannt.

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Summary The three speciesVeronica caespitosa Boiss. andV. bombycina Boiss. &Kotschy from high mountains of Asia Minor and the Lebanon andV. thessalica from high mountains of Northern Greece and Albania have not terminal but only one or a few lateral (axillary) raceme(s), the shoot ending sterile, continuing (prolificating) next year monopodially and developping again (a) lateral raceme(s) (fig. 1a, b). This fact hitherto has been concealed by the habit of these dwarfish undershrubs with densly crowded foliation, the raceme(s) overlapping and putting aside the short terminal shoot (fig. 1a). Thus the three species mentioned have to be transferred from the sectionVeronicastrum with terminal racemes to the sectionVeronica (=Chamaedrys), characterized by bearing only lateral racemes. V. thessalica until now was recorded only from the Thessalic Olympos (Greece). A speciemen in the herbaria W and WU from the peak of the mountain Gjalica e Lumës (2470 m s. m.) in Northern Albania, misidentified asV. satureioides Vis., makes it probable, that the area of this species covers also the high mountains between Albania and the Thessalic Olympos.

     

RATE OF PROTEIN RENEWAL IN SPINAL MOTONEURONS OF ADOLESCENT AND OLD RATS

The rate of incorporation of [³⁵S]methionine and the turnover rate of proteins in spinal motoneurons were studied in adolescent and old rats. The radioactivity of proteins was estimated by quantitative autoradiography and direct counting of beta radiation from samples of neurons isolated by free hand dissection. Both methods showed that the rate of incorporation into spinal motoneurons was significantly lower in old animals. By measuring the turnover rate of proteins in spinal motoneurons at least two protein components could be distinguished by their different turnover rates. The short-lived component had an average half-life of 2-2-2-8 days, the long-lived protein component had an average half-life of 27-38 days. Neither in the short-lived component, nor in the long-lived component was it possible to detect a significant difference between adolescent and old rats.     

Stomatal Opening in Isolated Epidermal Strips of Vicia faba. II. Responses to KCl Concentration and the Role of Potassium Absorption

The stimulation by KCl of stomatal opening in isolated epidermal strips of Vicia faba was examined. In dark + normal air the opening response was maximal at 100 mm KCl while in light + CO₂-free air it was maximal at about 10 mm KCl. CO₂-free air was more influential than light in reducing the KCl concentration required for maximal opening. K⁺ was essential while Cl⁻ seemed to be of secondary importance in these processes.     

Urinary excretion of and recent N-6-3 fatty acid intake

Epidemiological studies were performed in a Japanese fishing village when catches of fish were highest and in a Japanese farming village with usual fish consumption. Intake of eicosapentaenoic, docosahexaenoic and also arachidonic acid were significantly higher in the fishing village during the 3 days of the study than in the farming village. The correlation between eicosapentaenoic acid intake on the day when urine was collected and excreion of Δ 17-2,3-dinor-6-keto-prostaglandin F_1α, the main urinary metabolite of prostaglandin I₃, was highly significant, whereas there was no correlation between arachidonic or linoleic acid intake and excretion of 2,3-dinor-6-keto-prostaglandin F_1α, the main urinary metabolite of prostaglandin I₂. We suggest that the arachidonic acid pool for prostaglandin I₂ production is not quickly influenced by dietary linoleic or arachidonic acid because of a large pool size of arachidonic acid and a slow conversion of linoleic acid to arachidonic acid, while prostaglandin I₃ formation is directly related to the intake of eicosapentaenoic acid.     

Cyproheptadine metabolites inhibit proinsulin and insulin biosynthesis and insulin release in isolated rat pancreatic islets

The contribution of drug metabolites to cyproheptadine (CPH)-induced alterations in endocrine pancreatic -cells was investigated by examining the inhibitory activity of CPH and its biotransformation products, desmethylcyproheptadine (DMCPH), CPH-epoxide and DMCPH-epoxide, on hormone biosynthesis and secretion in pancreatic islets isolated from 50-day-old rats. Measurement of (pro)insulin (proinsulin and insulin) synthesis using incorporation of ³H-leucine showed that DMCPH-epoxide, DMCPH and CPH-epoxide were 22, 10 and 4 times, respectively, more potent than CPH in inhibiting hormone synthesis. The biosynthesis of (pro)insulin was also inhibited by CPH and DMCPH-epoxide in islets isolated from 21-day-old rat fetuses. The inhibitory action of CPH and its metabolites was apparently specific for (pro)insulin, and the synthesis of other islet proteins was not affected. Other experiments showed the metabolites of CPH were active in inhibiting glucose-stimulated insulin secretion but were less potent than the parent drug in producing this effect. CPH and its structurally related metabolites, therefore, have differential inhibitory activities on insulin synthesis and release. The observation that CPH metabolites have higher potency than CPH to inhibit (pro)insulin synthesis, when considered with published reports on the disposition of the drug in rats, indicate that CPH metabolites, particularly DMCPH-epoxide, are primarily responsible for the insulin depletion observed when the parent compound is given to fetal and adult animals.Abbreviations CPH cyproheptadine - CPH-epoxide cyproheptadine-10-11-epoxide - DMCPH desmethylcyproheptadine - DMCPH-epoxide desmethylcyproheptadine-10,11-epoxide - HPLC high-performance liquid chromatography - KBB Krebs biocarbonate buffer Recipient of a Society of Toxicology Predoctoral Research Fellowship.Present address: Department of Biochemistry, The University of Hong Kong, Hong Kong.     

Ultrastructure of calcitonin gene-related peptide-and substance P-like immunoreactive nerve fibres in the carotid body and carotid sinus of the guinea pig

Summary Previous studies have demonstrated that substance P-(SP) and calcitonin gene-related peptide-like immunoreactivities (CGRP-LI) coexist in sensory nerve fibres in the guinea-pig carotid body and carotid sinus. In the present study the ultrastructure of these nerve fibres was investigated by means of single-and double-labelling immunocytochemistry. In both, carotid body and carotid sinus immunoreactive fibres were unmyelinated axons of small dianeter (0.12–0.56 m). At the subcellular level, SP-and CGRP-LI were colocalized in intra-axonal dense core vesicles, suggesting corelease and simultaneous action of these two compounds. SP/CGRP-LI nerve fibres within the carotid body were mainly found in the interparenchymal connective tissue, but also occurred in relationship to blood vesslesl and nests of glomus cells. Neither in the carotid body not in the carotid sinus, SP/CGRP-LI axons corresponded to the large terminals which are generally considered to represent the main chemoreceptor and baroreceptor endings, respectively. Thus, SP/CGRP-LI fibres either belong to the chemo-and baroreceptors of the C-fibre class or constitute a fibre population not directly involved in conduction of baro-and chemoreflexes.This study was supported by the DFG, grant He 919/6-2