Cardiac activation and inhibition involved in molting behavior of a spiny lobster

To study the molting behavior of the spiny lobster, electrical activity of the heart, stomach and skeletal muscles was recorded using in-dwelling electrodes. For 1–2 h before molting the heart rate gradually increases. At the same time shorter trains of stomach burst discharges frequently occur. The heart rate then declines and burst discharges of skeletal muscles begin. The skeletal bursts are regularly spaced (10–15 s intervals). A peristalsis pattern of short and long bursts continues for 10–20 min and is terminated by a few bursts corresponding to abdominal flips. The short skeletal burst is followed by a drop in heart rate. Bioassay using the isolated heart suggests that at the final stage of molting the blood contains some substance(s) which inhibit heart beat.     

Neuromodulation by serotonin and octopamine in the honeybee: behaviour,neuroanatomy and electrophysiology

The biogenic amines serotonin (5HT) and octopamine (OA) exist in the bee and can modulate neuronal activity and behaviour. 5HT-like and OA-like immunoreactivities can be found in most neuropils of the brain. Binding sites for the two amines are also present in most brain neuropils. The highest density of binding sites for [³H]serotonin and [³H]octopamine was found in the mushroom bodies. In some brain areas, especially the mushroom bodies, mismatches exist between binding sites and immunoreactivities, suggesting that the two amines also bind to neuropils which are not directly innervated by 5HT-like or OA-like immunoreactive neurons. The action of the two amines on behaviour in the bee is antagonistic. In the antennal pathway, proboscis and antennal responses to olfactory and gustatory stimuli are enhanced by OA and reduced by 5HT. In olfactory conditioning experiments, storage and retrieval of the learned signal can be enhanced by OA and reduced by 5HT. The specificity of these effects depends on the site of amine application in the neuropil. In the visual system the direction specificity of the visual antennal response is enhanced by OA and reduced by 5HT after topical application or injection into the lobula, the third optic ganglion. Correlates for the behavioural modulation can be found in higher-order visual interneurons. While OA application can mimic the stimulation of the bee with sugar water, the behavioural conditions leading to the release of 5HT are not yet known.     

Exocytosis of secretory granules — a probable mechanism for the release of neuromodulators in invertebrate neuropiles

Summary Presynaptic terminals typically contain secretory granules, usually 100–200 nm in diameter, in addition to the smaller synaptic vesicles. Evidence is presented that granule exocytosis is a widespread phenomenon in invertebrate neuropiles. Such secretory release is apparently associated with morphologically unspecialized regions of the plasmalemma, rather than synaptic thickenings.Acknowledgments. The authors gratefully acknowledge the assistance of Mr R. M. Hewit and Mrs. S. Al-Yousuf. Supported by research grant GR/A88743 from the S.E.R.C., U.K., to D.W. Golding.     

Analysis of the L-type S-potential by means of the stiles-crawford effect in the carp retina

Zusammenfassung Mit Hilfe des « Stiles-Crawford»-Effektes gelingt es, die Existenz blau-empfindlicher Zäpfchen in der Fischretina nachzuweisen, die teilweise für die S-Potentiale verantwortlich sind.     

The determination of orotic acid in the blood serum by means of the spectrophotometric method

Zusammenfassung Das Prinzip des Orotsäurenachweises beruht auf der Deproteination des Serums mittels Uranylessigester und der Verwandlung der Orotsäure durch Bromation in 5,5-Dibrombarbitursäure und nachfolgende Debromation in Barbitursäure. Letztere ergibt mitp-Dimethylaminobenzaldehyd ein intensiv gefärbtes Produkt, 5-(p-dimethylaminobenzyliden)-Barbitursäure.     

Modulation of humoral immunity in the mouse by means of grafts carrying reticulated polysaccharides]

Synthetic reticulated polysaccharides grafted with linear amino-acids or amines have been submitted to the test of localized hemolysis in gel (Jerne). Some of them show a statistically highly significant immuno-stimulating power in Mice.     

The young notochord can induce somite genesis by means of diffusible substances in the chick

Résumé L'utilisation de fragments de filtre millipore, intercalés entre un fragment de ligne primitive et un explantat de jeune chorde, nous permet de démontrer présentement que l'induction des somites par la chorde s'opère par le truchement de substances diffusibles chez les oiseaux.

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This work was generously supported by the Fonds National de la Recherche Scientifique, Bern (Switzerland).     

Quarterly forecasts of the italian business cycle by means of monthly economic indicators

Recent years have witnessed a growing availability of high-frequency indicators which can be used to forecast future economic activity. This paper shows how some of the widely known monthly economic indicators at present available in Italy can be used in a systematic and coordinated manner to forecast the main variables of the National Accounts. In order to reduce as much as possible the amount of judgment in the analysis of the business cycle, a model-based approach is adopted. Thus, a pseudo macro-econometric model of the Italian economy is built, which can be used to produce forecasts one semester ahead of the last National Accounts data release. The model can be used autonomously as well as in combination with the Bank of Italy's quarterly econometric model.     

Frequency and distribution of tubulo-filamentous nuclear inclusions in the celiac ganglion of the cat as revealed by serial sections.

On sections at random of a cat celiac ganglion we counted 68 sections of nuclear inclusions (NI) for 320 sections of neuronal nuclei, i.e. an "apparent' frequency of 0.20. As revealed by serial sections the "actual' frequency is higher since the 5 nuclei entirely explored exhibit 19 NI. Such a study shows that each nucleus may contain at least 3 and up to 5 different tubulo-filamentous NI.     

Some new data on the number of chromosomes of teleost fish obtained by means of tissue culture in vitro

Riassunto In questa nota vengono riportati nuovi dati sul numero dei cromosomi di alcune specie di pesci teleostei.