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At least 73 records · Page 4Linked to original sources
PubMed1989

Monosynaptic connections between serotonin-containing neurones labelled by 5,6-dihydroxytryptamine-induced pigmentation in the snail Helix pomatia L.

Microelectrophysiological experiments were carried out on in vivo 5,6-dihydroxytryptamine-induced pigment-labelled serotonin-containing neurones of Helix pomatia. Excitatory chemical monosynaptic connections were found between the giant pedal LP3 neurone and several follower cells in the visceral and right parietal ganglia. These neurones have previously been described to be involved in regulation of visceral functions. Monitoring changes in identified monosynaptic connections between pairs of serotonin-containing neurones aids the cellular analysis of behavioural plasticity.

5,6-Dihydroxytryptamine↗
PubMed1992

Sarcoplasmic calcium-binding protein-immunoreactive material in the central nervous system of the snail, Helix pomatia.

In Helix pomatia a 10 kDa sarcoplasmic calcium binding protein I (SCP I)-immunoreactive material was localized immunologically in neurons of the central nervous system, including the electrically silent serotonergic metacerebral giant neuron. Antisera against sarcoplasmic calcium binding protein II (SCP II) stained a 20 kDa protein in individual muscle cells of the epineurium. SCP- and parvalbumin (PV)-immunoreactive material were not co-localized.

Animals↗
PubMed1987

Localization of ARG-vasopressin-like material in central neurones and mechanism of action of ARG-vasotocin on identified neurones of the snail Helix aspersa.

Immunocytochemical and electrophysiological studies were made on neurones in the suboesophageal ganglia of Helix aspersa. A group of neurones in the anterior dorsal surface of each parietal ganglion showed positive immunoreactivity to an antibody to arginine vasopressin (AVP), as did the neuropile and the nerves associated with the parietal and visceral ganglia. The only peripheral tissue to exhibit positive immunoreactivity to AVP was the optic tentacle, where positive immunoreactive fibres were present in the optic nerve and cell bodies below the retinal cell layer. Two central neurones, F1 and E13 were excited by arginine vasotocin (AVT), threshold 1-10 nM, and the ionic mechanism associated with this response was investigated. This excitation involved both sodium and calcium ions with an overall increase in resistance. In low sodium Ringer, the AVT response was greatly reduced, while in calcium-free 3 mM cobalt Ringer, the response was potentiated. Changing the external concentrations of potassium and chloride ions had no apparent effect on the response. The amplitude of the excitation induced by AVT was enhanced when the cells were hyperpolarized. Most of the other neurones tested failed to respond to AVT though the excitatory response of certain cells to acetylcholine was enhanced by 0.1 microM AVT. Excitation by 5-hydroxytryptamine was unaffected in the cells tested. This study provides further evidence for a role for an AVT-like peptide in the nervous system of Helix.

Acetylcholine↗
PubMed1994

Actions of Fusinus FMRFamide-related peptides on the identified central neurones of the snail, Helix aspersa.

The actions of Fusinus FMRFamide-related peptides, that is FMRFamide, FLRFamide, GSLFRFamide, SSLFRFamide, the analogue, GSFFRFamide, and the fragments, LFRFamide and RFamide, were examined on the F1, F2 and F5 neurones of Helix aspersa. All Fusinus peptides exhibit an inhibitory effect on F1 and F5 neurone. On F2 neurone, FMRFamide and FLRFamide exhibit an excitatory effect but GSLFRFamide and SSLFRFamide exhibit an inhibition. The fragment, LFRFamide, is 10-times less potent than GSLFRFamide. GSFFRFamide and RFamide are inactive on F1, F2 and F5 neurone. This evidence indicates that the fragment, LFRFamide, is crucial for the biological activity of Fusinus hexapeptides. The inhibition induced by Fusinus hexapeptides had a reversal potential around -75/-80 mV. It was potentiated in K(+)-free saline, partially abolished either in 10 mM TEA or in 10 mM Co2+ saline and completely abolished in 500 microM 4-AP saline. This evidence indicates that there are multiple K+ channels which are activated by Fusinus hexapeptides and that the IA is more susceptible than IK and IKCa to these peptides.

Acetylcholine↗
PubMed1985

The effects of capsaicin on action potential and outward potassium currents in a bursting neuron of the snail, Helix pomatia L.

The effects of capsaicin (CAP) on membrane properties, action potentials (APs) and outward membrane currents were investigated using the single electrode current and voltage clamp. CAP (60-300 microM) depolarized the cell membrane and increased the input resistance (Rin). The burst frequency of the neuron simultaneously increased. CAP prolonged the APs and attenuated the outward currents with decreasing potency in the sequence of the early outward current (IA), an early and a late component of the delayed outward current.

Action Potentials↗
PubMed1994

Distribution of NADPH-diaphorase in the perioesophageal ganglia of the snail, Helix aspersa.

In this paper we discuss the anatomical localization of NADPH-diaphorase using Nitroblue tetrazolium in perioesophageal ganglia of Helix aspersa. Our results show that the reaction is present in neurons and fibers of the procerebrum, some positive neurons are found in mesocerebrum, and there were positive fibers in the neuropile of postcerebrum and mesocerebrum; likewise, immunopositive fibers were found in the neuropile of pedal, pleural and parietal ganglia. The presence of NADPH-diaphorase in the interneurons of procerebrum suggests the participation of this enzyme in the production of nitric oxide for the processing of the olfactory information, as has been suggested in mammalian olfactory tissue.

Animals↗