Growth and srif-like substance(s) in the snail Helix aspersa maxima fed with an arginin-enriched food at different times of a short daily photophase

Oscillatory dynamics and information processing in olfactory systems

Oscillatory dynamics is a universal design feature of olfactory information-processing systems. Recent results in honeybees and terrestrial slugs suggest that oscillations underlie temporal patterns of olfactory interneuron responses critical for odor discrimination. Additional general design features in olfactory information-processing systems include (1) the use of central processing areas receiving direct olfactory input for odor memory storage and (2) modulation of circuit dynamics and olfactory memory function by nitric oxide. Recent results in the procerebral lobe of the terrestrial slug Limax maximus, an olfactory analyzer with oscillatory dynamics and propagating activity waves, suggest that Lucifer Yellow can be used to reveal a band-shaped group of procerebral neurons involved in the storage of an odor memory. A model has been constructed to relate wave propagation and odor memory bands in the procerebral lobe of L. maximus and to relate these findings to glomerular odor representations in arthropods and vertebrates.

Erythromycin elicits opposite effects on antro-bulbar and duodenal motility: analysis in diabetics by cineradiography

We have previously demonstrated by cineradiography analysis that erythromycin (Ery) increases antral contractility and antropyloric coordination in diabetics. The aim of this study was to further characterize antro-bulbar and duodenal motility after Ery i.v. administration. Fourteen diabetic patients (mean age 61.2 years) were randomly allocated to receive either 100 or 500 mg of Ery intravenously 4 hours after a standard solid liquid meal. After ingestion of a barium sulfate suspension, a series of 15 fluorographic plates (one every two seconds) was performed. the same procedure was repeated twice for each subject with a delay of 3 days once before and once after Ery. Antral, bulbar and duodenal areas and evolution diagrams were calculated in baseline conditions and after Ery administration using a graphic table connected to a microcomputer. No differences were found between the two doses of the drug. Ery significantly decreased antral (1284 +/- 268 mm2 vs 704 +/- 181 mm2; P < 0.01) and bulbar areas (127 +/- 26 mm2 vs 73 +/- 21 mm2; P < 0.01). In contrast, duodenal areas were significantly increased after Ery (875 +/- 112 mm2 vs 575 +/- 112 mm2; P < 0.01). This study suggests that the known prokinetic effect of Ery on gastric emptying seen in diabetic patients could be related to an increase of motility in the antrum and in the bulb simultaneously with a relaxation in the duodenum.

In vitro effects of methionine-enkephalin, somatostatin and insulin on cultured gonadal cells of the snail Helix aspersa

Isolated snail gonadal cells were cultured in the presence of synthetic neuropeptides in order to determine the subsequent effect of these substances on gonadal synthetic activities. Gonadal cells were incubated for 24 h in concentrations of methionine-enkephalin, somatostatin and insulin ranging from 10(-4) M to 10(-9) M, in medium 199 supplemented with 6% Ultroser G. Synthesis of DNA and protein by the cultured cells were simultaneously estimated by measuring incorporation of 3H thymidine and 35S methionine. The rate of labelled precursor incorporation was measured using the liquid scintillation technique. All substances tested exerted a dose-dependent effect. The synthetic activity of the cultured cells was highest when the concentration of the peptides added to the medium approximated the physiological levels. Methionine-enkephalin, somatostatin and insulin at 2 x 10(-8) M significantly increased 3H thymidine incorporation, by 62%, 69% and 69% respectively, and protein synthesis by 42%, 57% and 57%, respectively. In the case of juvenile gonadal cultured cells, a similar increase in 3H and 35S incorporation was registered for a 10(-7) M peptide concentration. Both lower and higher peptide concentrations inhibited 3H thymidine and 35S methionine incorporation. Pharmacological studies suggest the existence of methionine-enkephalin and somatostatin-like receptors on snail gonadal cells. These results indicate that our gonadal cell culture model provides a useful tool for the study of the neuroendocrinological control of the activity of snail gonadal cells.

[Longitudinal component of gastric motility: its relationship to peristaltic velocity and contractility. Cineradiographic study in man]

The aim of this study was to further characterize the gastric longitudinal motility and its relationship between the peristaltic velocity and contractility. Twelve healthy volunteers (six made sport S and six were sedentary NS; moy +/- DS; 24 +/- 2.4 years; 172 +/- 3.9 cm; 65.8 +/- 3.4 kg; n = 12) were involved and ingested 5 hours after a standard meal, 250 ml of barium sulfate suspension. A serial of 15 fluoroscopic plates (size 10 x 10 cm) was taken in 30 seconds. For each subject, the longitudinal variation delta L (cm) of gastric shape, the mean velocity V (mm/s) of gastric peristalsis and the intensity AM (p 100) of contractile wave were measured with a digitalized table connected to a computer. Compared to NS group, the S group showed significative enhanced values of the dynamic parameters (delta L: 2.9 +/- 0.4 vs 1.8 +/- 0.2 cm; V: 2.8 +/- 0.2 vs 2.3 +/- 0.2 mm/s; AM: 55.8 +/- 5.3 vs 48.3 +/- 2.8 p 100; moy +/- DS). Faster rhythms were observed in the diagram of longitudinal motility, with or without the well known gastric frequency 3 c/min. This study allows to point out longitudinal changes of the gastric shape and shows a pattern of significant augmented gastric motility. In fact, it is necessary to consider the stomach in a biomechanical system with the diaphragm and the abdominal wall. This system influenced by exercise might be studied intensively with our dynamic parameters associated with respiratory and abdominal data.