Naloxone selectively blocks dopamine response of Br-type neuron in Helix pomatia L.

The present study demonstrates that the potent opiate antagonist, naloxone can selectively block the DA induced inhibition of the bursting activity pattern of the RPal or Br-type neuron. The dopamine inhibitory affect can also be blocked by haloperidol, a established dopamine receptor blocker.     

Monoamine oxidase activity in Helix pomatia.

The distribution and characterization of MAO in various tissues of the snail were analyzed. Only low amounts of the enzyme exist in the different tissues and data suggest that there is more than one type of MAO.     

Methionine enkephalin inhibits the bursting activity of the Br-type neuron in Helix pomatia L

The present study demonstrates that methionine enkephalin can inhibit the normal bursting activity pattern of the RPal or Br-type neuron and this inhibition can be blocked by prior treatment with naloxone, the selective opiate antagonist. The study demonstrates indirectly the presence of opiate-like receptors in Helix pomatia.     

In vitro biosynthesis of octopamine by the nervous system and the heart of the mollusc gastropode Helix pomatia (author's transl)]

The tyrosine is decarboxylated in vitro by the central nervous tissue and by the intracardiac nervous tissue of Helix pomatia by aromatic amino-acid decarboxylase. The tyramine obtained is then partially transformed into octopamine by tyramine-beta-hydroxylase. The inhibition of monoamine oxidase favours apparition of the 2 amines. The monoamine oxidase seems able to regulate their synthese and to assure their inactivation.     

Degradation of bacterial lipopolysaccharide by gut juice os the snail Helix pomatia.

Lipopolysaccharides from several bacteria were selectively degarded by gut juice of the snail Helix pomatia with extensive loss of anticomplementary activity and changes in the electrophoretic pattern in polyacrylamide gels. The gut juice had little effect on ketodeoxyoctonate content or immunodominant sugars. The lipid A moiety of the lipopolysaccharide appeared to be the main site of attack.     

Interaction between two identified cells in the visceral ganglion of the snail, Helix pomatia.

An interneurone, making excitatory synaptic connections with a second neurone has been identified in the brain of Helix pomatia. The results suggest that the connection is monosynaptic.     

The occurrence of ¦ bipolar neurons in the abdominal mass ganglia of a pulmonate mollusc (Cryptomphallus aspersa)

Resumen Se describen en la masa ganglionar ventral del moluscoCryptomphallus aspersa (Gasteropoda, Pulmonata) la presencia de varios tipos de neuronas bipolares entremezcladas con las típicas unipolares. Estas observaciones morfológicas se discuten en relación a los hallazgos obtenidos previamente con técnicas electrofisiológicas por otros autores.     

Aluminium in repair membranes and Al,Ca and Pi in the haemolymph of Al-injected shell-repairing snails (Helix pomatia L.)

Summary In AlCl₃-injected shell-repairing snails,Helix pomatia L., the Al-associated decrease of the weights of the shell-repair membranes was unrelated to the Al-concentration in the membranes. In the haemolymph the concentration of Al was related to the dose of injected Al, while the concentration of Ca was increased by the highest Al-dose only. No phosphate was detected in either controls or Al-injected snails. It is concluded that Al inhibits the growth of the CaCO₃-crystals by mechanisms other than incorporation in, or adsorption to, the crystals.     

Interactions between two identified cells in the visceral ganglion of the snail,Helix pomatia

Summary An interneurone, making excitatory synaptic connections with a second neurone has been identified in the brain ofHelix pomatia. The results suggest that the connection is monosynaptic.We thank the M.R.C. for a Training Grant to S.E.J.     

Synaptic connections made by two serotonin-containing neurons in the snail (Helix pomatia) brain

Résumé On décrit la disposition précise des contacts synaptiques réalisée par deux gigantesques neurones contenant de la sérotonine (GSC) avec d'autre neurones dans la cervelle de l'escargotHelix pomatia. Quelques neurones sont innervés deux fois par chaque GSC.