[Effect of modafinil on electroretinograms of Lycosa tarentula in relation visual circadian rhythm (Araneae, Lycosidae)].

Injections of modafinil, a drug able to induce in vertebrates an awakening effect via an effective central alpha 1-adrenergic tone, induce modifications of the amplitude and latency of electroretinograms (ERGs) in the spider Lycosa tarentula, during dark adaptation. Results of experiments are different from one eye type to another as circadian activity rhythms of the retinae also differ. Modafinil induces a decrease of diurnal amplitudes and has no effect on nocturnal amplitudes of ERGs of anterior-lateral eyes; in the case of posterior-median eyes, the amplitudes are increased in daytime as well as at night.

Spontaneous electrical activity of the suboesophageal ganglion and circadian rhythms in scorpions.

The electrical activity of the suboesophageal ganglion of the scorpion Euscorpius flavicaudis was recorded. Four kinds of waves were observed: random waves, single pattern, periodic waves and perturbed periodic waves. While random waves and single pattern could be recorded at any time of the day, periodic waves were observed only during the night.

Electroretinographic study of the white mouse intoxicated by organo-phosphorus: mevinphos and malathion.

Evidence is given that the organo-phosphates mevinphos and malathion perturb the retinal functioning of the white mouse by acting 1. directly on the photoreceptors; 2. by a synaptolytic effect due to the inhibition of cholinesterases; 3.

[Effect of chemically related organochloric pesticides on the electro-ocular response of the white mouse].

Chlordane, aldrin and dieldrin act on the bipolar neurones and the repolarization of the photoreceptors. Only aldrin and dieldrin disturb photoreceptor excitability. Taking account of experimental results previously obtained with DDT and HCH, a relation between chemical structure and retinian toxicity has been proved.