[The effect of light intensity and neostigmine on the electroretinogram of Drosophila melanogaster]. / Influenta intensitatii luminoase si a neostigminei asupra electroretinogramei la Drosophila melanogaster.

In this article is presented the influence upon the electroretinogram, of some external factors acting at different levels of the visual system in the fruit fly, Drosophila melanogaster. The experiments revealed the effects generated by the light intensity modification as well as by the injection of a neuropharmaceutic--the neostigmine. The increase of the light stimuli intensity induced the same change of the rate between the amplitudes of the main electroretinographic components as the neostigmine does. It was used the "flickering" excitation regime, utilizing a data acquisition system adapted to the principal experimental device.

Selective interaction model and photoreceptor cell membrane.

A mathematical model is proposed in order to describe, from the thermodynamic point of view, the changes in the photoreceptorcell membrane induced by light stimuli. The phenomenologicalbackground is the increase of the fly microvillar membrane ionicconductivity as a consequence of Ca(++-)Na(+) affinity modification under light action. On the basis of the analogywith the model of protein interaction in mixed solvents, themodel is focused on the selective interaction between ionchannels gates and two ionic ligands. Three possible theoretical cases are examined.