P. Heilig

Die wirkung von psychopharmaka auf die aktivität retinaler neurone

Abstract Using microelectrodes the activity of a total of 328 single fibers of the optic nerve was recorded in 37 cats. The influence of Chlorpromazin, Butyrylperazine, Chlorprothixen, Spiroperidol, Desipramin, Amitriptyline and Diazepam on spontaneous and light induced activity was investigated. With increasing doses of the psycho-pharmacological agents the spontaneous activity decreased significantly. Diazepam altered the type of nonsequential interval histograms: In spite of the decreased frequency the histograms were uni- or bimodal under the influence of the studied drugs except Diazepam. With this substance multimodal distributions appeared. The phasic response of the neurons to light stimuli was only slightly altered. Under the influence of Desipramin and Amitriptyline strong reactions to the stimuli without any spontaneous activity of the fibers were observed. The results in connection with the findings of other investigators show a direct influence of psycho-pharmacological agents on the neural net of the retina. The results support the assumption of the existence of synaptic transmitters in addition to acetylcholine and catecholamines.

EOG and ERG Components in Ischemic Retinopathy

In 12 adult subjects with ischemic retinopathy and in 2 children with surgically dissected retinal artery EOG light peaks and dark troughs were recorded. Standing potentials, light-induced potentials and dark troughs were reduced significantly in all affected eyes. Standing potential, light-induced oscillation and dark oscillation do not only depend upon the pigment epithelium/receptor unit; the integrity of the inner retinal structures is also of significance. The analysis of slow EOG components alone does not allow to localize and determine the level of retinal defects.

Die wirkung von psychopharmaka auf visuell evozierte potentiale der katze

Abstract Visually evoked potentials were recorded from the visual cortex of 25 cats and the changes due to the influence of Chlorpromazin, Butyrylperazin, Chlorprothixen, Haloperidol, Desipramin, Amitriptyline and Diazepam were investigated. The latencies of the responses increased with increasing doses of the agents, the on-responscs in the evoked potentials of most of the animals were enlarged. In some experiments off-responses could be seen only under the influence of psychopharmacological drugs; in most animals the amplitude of the off-responses increased according to higher dosage. The visually evoked potentials were accentuated under the influence of these drugs. The effects may be interpreted as caused by reduction of activating influences from other parts of the brain to the visual cortex and by the decrease of spontaneous activity in the primary afferent system.

Intraoperative retinal light damage reflected in electrophysiologic data

In a series of 30 unilaterally pseudophakic patients, electroretinograms and electrooculograms were recorded 6 months postoperatively. The unoperated on fellow eyes served as controls High intraoperative retinal light exposure (3.4–7.3 mW/cm2, Zeiss OPMI 6 operating microscope) caused a substantial reduction of electrophysiologic potentials. Light protection prevented deterioration of electroretinogram and electro-oculogram potentials; reducing the bulb voltage, tilting the axis of illumination, filtering short wavelengths and the use of light shields resulted in 4-log-unit lower intensities (0.8–3.7 μW/cm2).

The influence of intravitreously injected silicone oil on electrophysiological potentials of the eye

In a prospective study the effect of silicone oil injected in the vitreous cavity was monitored electrophysiologically in six patients who were treated for retinal detachment. Electroretinograms (ERG) and electrooculograms (EOG) were recorded before, shortly after, and up to four months following the removal of the oil. An evident increase of the standing potential could be observed in all eyes after removal of the silicone oil. In some patients the ERG amplitudes increased also. No fast oscillations and virtually no slow oscillations could be recorded in the EOG. Follow-up studies did not show a significant recovery of the bioelectric activity. Intravitreal silicone oil appears to cause an insulation effect which interferes with the propagation of electrical potentials. The result of the present study do not provide information concerning possible retinotoxic effects of silicone oil.

ERG and EOG in progressive paravenous retinochoroidal atrophy.

A case of paravenous retinochoroidal atrophy was followed over a period of more than 2 years. Rapid progression of the disease was reflected in the deterioration of visual acuity and fields. Electroretinographic recordings revealed reduced photopic and scotopic amplitudes according to the extent of the retinal lesions. In electro-oculography virtually no slow and no fast light-induced oscillations could be recorded. These results suggest an involvement of the entire retinal pigment epithelium.

Fast and Slow EOG Oscillations in Congenital and Acquired Night Blindness

In congenital night blindness of the Schubert-Bornschein type both fast and slow EOG oscillations were found to be normal. In acquired night blindness due to vitamin A deficiency no EOG oscillations a

Fast Oscillation of the Corneoretinal Potential in Ischemic Retinopathy

Clinical electro-oculographic examinations were performed in 21 subjects with unilateral occlusion of the central retinal artery. The values from the unimpaired fellow eyes were used as normal data fo

The Fast Oscillation of the Electro- Oculogram

The dependence of amplitudes and peak latencies of the light-induced fast EOG oscillation was studied using rectangular light stimulation. A linear increase of the amplitude was observed in the intensity range tested (24–3,000 asb). No influence of the time of preadaptation to darkness on the amplitudes could be proven in a range of 20 s to 21 min. The peak latency was not dependent on light intensity. Prolonged peak latencies were observed following short and long periods of dark adaptation.

Die aktivität von Einzelfasern des nervus opticus bei verschiedenen temperaturen

SummaryThe activity of 128 single fibers of the optic nerve was recorded in 13 cats at temperatures between 27 and 39° C. Nonsequential interval histograms were computed on line. Decreasing temperature diminished the mean frequency of the fiber activity from 56/sec at 37–39° C to 21/sec below 29° C. Above 35° C the histograms were unimodal or bimodal, the first peak caused by repetitive discharges. Below 35° C multimodal histograms appeared; in some distributions several peaks were superimposed. At temperatures below 29° C only multimodal distributions were obtained. The phasic response of the neurons to light showed an increase of latency and of inhibition according to the decrease of temperature. Often the type of the response of the neuron could not be recognized below 30° C. During hypothermia interactions in the retina may be reduced and this may explain why multimodal distributions occur more frequently.ZusammenfassungIn 13 Katzen wurde die Aktivität von 128 Einzelfasern des N. opticus bei Temperaturen zwischen 27 und 39° C abgeleitet und direkt einer Intervallanalyse zugeführt. Die Durchschnittsfrequenz sank mit abnehmender Temperatur von 56/sec bei 39–37° C auf 21/sec unter 29° C. Bei Temperaturen über 35° C wurden nur unimodale oder zweigipfelige Verteilungen mit gehäuften Mehrfachentladungen gefunden. Unter 35° C traten multimodale Intervallhistogramme und Übergangstypen auf, bei denen einer Verteilung mehrere Gipfel aufgesetzt erschienen. Unter 29° C wurden nur mehrgipfelige Verteilungen beobachtet. In der phasischen Reaktion der Neurone wurden mit der Temperaturabnahme Latenzen länger und Hemmungen stärker. Unter 30° C konnte der Reaktionstyp des Neurons oft nicht mehr erkannt werden. Das vermehrte Auftreten multimodaler Verteilungen bei niedrigen Temperaturen ließe sich durch Verminderung von Interaktionen in der Retina erklären.Die Anregung zu dieser Untersuchung wurde von Herrn Professor Dr. Hans Bornschein gegeben.