Neurotoxic effects evoked by cyanobacterial extracts suggest multiple receptors involved in electrophysiological responses of molluscan (CNS, heart) models.

The responses of the snail central neurons (Helix pomatia, Lymnaea stagnalis) and the isolated Helix heart were characterized evoked by cyanobacterial extracts (Cylindrospermopsis raciborskii ACT strains) isolated from Lake Balaton (Hungary). The nicotinergic acetylcholine (ACh) receptors in the CNS (both excitatory and inhibitory) were blocked by the extracts of ACT 9502 and ACT 9505 strains and the anatoxin- a (homoanatoxin-a) producing reference strain of Oscillatoria sp. (PCC 6506), similar to the inhibitory effects of the pure anatoxin-a.

Effects of rotenone and other mitochondrial complex I inhibitors on the brine shrimp Artemia.

(Artemia) nauplii was used to asses the toxicity of rotenone, MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine), MP+ (1-methyl-4-phenylpyridinium) and the effect of L-DOPA co-treatment with rotenone. Rotenone had a dose dependent effect on mortality (LC₅₀: 0.37 ± 0.

The terrestrial snail, Helix pomatia, adapts to environmental conditions by the modulation of central arousal.

The osmotic stimulation which is able to change the behavioral state of the animal are most effective during rainy weather while they are less effective during dry weather conditions. In isolated CNS preparations from aestivated animals the highest firing activity and serotonin sensitivity of the serotonergic (RPas) heart modulator neurons are recorded during rainy weather and the lowest parameters are observed in dry conditions. In aestivated animals the serotonin (5HT) content in both the CNS and the foot is higher than the dopamine (DA) content during rainy weather, while in dry weather the DA level is higher than the 5HT.

Behavioural and neural deficits induced by rotenone in the pond snail Lymnaea stagnalis. A possible model for Parkinson's disease in an invertebrate.

Parkinson's disease is a neurodegenerative disorder, related to the loss of dopamine (DA)-containing neurons in the substantia nigra. In experimental animals, both vertebrates and invertebrates, rotenone, a commercially available organic pesticide, induces symptoms of Parkinson's disease. We found that that rotenone is toxic to the pond snail Lymnaea stagnalis (4-day LC50 0.

Octopamine increases the excitability of neurons in the snail feeding system by modulation of inward sodium current but not outward potassium currents.

Background: Although octopamine has long been known to have major roles as both transmitter and modulator in arthropods, it has only recently been shown to be functionally important in molluscs, playing a role as a neurotransmitter in the feeding network of the snail Lymnaea stagnalis. The synaptic potentials cannot explain all the effects of octopamine-containing neurons on the feeding network, and here we test the hypothesis that octopamine is also a neuromodulator.

Results: The excitability of the B1 and B4 motoneurons in the buccal ganglia to depolarising current clamp pulses is significantly (P < < 0.

Octopamine-containing (OC) interneurons enhance central pattern generator activity in sucrose-induced feeding in the snail Lymnaea.

In the pond snail Lymnaea stagnalis octopamine-containing (OC) interneurons trigger and reconfigure the feeding pattern in isolated CNS by excitation of the central pattern generator. In semi-intact (lip-mouth-CNS) preparations, this central pattern generator is activated by chemosensory inputs. We now test if sucrose application to the lips activates the OC neurons independently of the rest of the feeding central pattern generator, or if the OC interneuron is activated by inputs from the feeding network.

Second messengers of octopamine receptors in the snail Lymnaea.

We describe octopamine responses of 3 large buccal neurons of Lymnaea and test the hypothesis that these are cAMP-dependent. The B1 neuron is excited by octopamine and the depolarisation is significantly enlarged (P < 0.05) by application of the blocker of cAMP breakdown, 3-isobutyl-1-methylxanthine (IBMX).

Octopaminergic modulation of the membrane currents in the central feeding system of the pond snail Lymnaea stagnalis.

Octopamine is released by the intrinsic OC interneurons in the paired buccal ganglia and serves both as a neurotransmitter and a neuromodulator in the central feeding network of the pond snail Lymnaea stagnalis. The identified B1 buccal motoneuron receives excitatory inputs from the OC interneurons and is more excitable in the presence of 10 microM octopamine in the bath. This modulatory effect of octopamine on the B1 motoneuron was studied using the two electrode voltage clamp method.