cyclic-gmp and Paralysis

Phototaxis behavior is commonly observed in animals with light-sensing organs. C. elegans, however, is generally believed to lack phototaxis, as this animal lives in darkness (soil) and does not possess eyes. Here, we found that light stimuli elicited negative phototaxis in C. elegans and that this behavior is important for survival. We identified a group of ciliary sensory neurons as candidate photoreceptor cells for mediating phototaxis. Furthermore, we found that light excited photoreceptor cells by evoking a depolarizing conductance carried by cyclic guanosine monophosphate (cGMP)-sensitive cyclic nucleotide-gated (CNG) channels, revealing a conservation in phototransduction between worms and vertebrates. These results identify a new sensory modality in C. elegans and suggest that animals living in dark environments without light-sensing organs may not be presumed to be light insensitive. We propose that urbilaterians, the last common ancestor of bilaterians, might have already evolved a visual system that employs CNG channels and the second messenger cGMP for phototransduction.

Topics: Animals; Animals, Genetically Modified; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Cyclic GMP; Cyclic Nucleotide-Gated Cation Channels; Diltiazem; Dose-Response Relationship, Drug; Dose-Response Relationship, Radiation; Enzyme Inhibitors; Guanylate Cyclase; Ion Channels; Light; Motor Activity; Neurons, Afferent; Paralysis; Patch-Clamp Techniques; Ultraviolet Rays; Vision, Ocular

Cyclic GMP (cGMP) is responsible for various cellular functions including signal pathways and it acts as a mediator for nitric oxide (NO). In order to evaluate the anthelmintic efficacy of the plant-derived isoflavones, the crude peel extract of Flemingia vestita and pure genistein were tested with respect to the activity of nitric oxide synthase (NOS), NO efflux and the cGMP concentration in Rallietina echinobothrida, the cestode parasite of domestic fowl. For comparison, the parasites were also treated with genistein (the major isoflavone present in the crude peel extract), sodium nitroprusside (SNP), a known NO donor, and praziquantel (PZQ), the reference drug. At the time of onset of paralysis in the parasite, the activity of NOS showed a significant increase (35-46%) and a 2-fold increase of NO efflux into the incubation medium in the treated worms in comparison to the respective controls. The cGMP concentration in the parasite tissue increased by 46-84% in the treated test worms in comparison to the controls. The results show that the isoflavones, genistein in particular, from the crude peel extract of F. vestita influence the cGMP concentration in the parasite tissue, which plays a major role in the downstream signal pathways.

Topics: Animals; Anthelmintics; Cestoda; Cestode Infections; Cyclic GMP; Fabaceae; Genistein; Nitric Oxide; Nitric Oxide Synthase; Nitroprusside; Paralysis; Plant Extracts; Poultry Diseases; Praziquantel; Time Factors

Topics: Animals; Antipsychotic Agents; Apomorphine; Cerebellum; Corpus Striatum; Cyclic AMP; Cyclic GMP; Dopamine; Dopamine Antagonists; Drug Interactions; Ergolines; Hydroxydopamines; Motor Activity; Paralysis; Piribedil; Rats