Glukose-Wirkung auf die Stäbchenfunktion im isolierten, perfundierten Katzenauge

Zusammenfassung

Änderungen des Glucose-Spiegels (Standardwert 4,5-5,5 millimolar) in der Perfusionslösung isolierter Katzenaugen beeinflussen das Ruhepotential und die licht-evozierten Signale von DC-Elektroretinogramm, scotopic threshold response, und Aktionspotential des N. opticus mit parallelem Anstieg, bzw. Abfall. Die Wirkungen sind konzentrations-abhängig und reversibel. Diese Beobachtung hat Implikationen nicht nur für Physiologie von ZNS-Gewebe von Warmblütern in vitro, sondern auch klinisch für die Netzhaut unter metabolisch veränderten Bedingungen.

Summary

Effects of changing glucose concentration on light-evoked, rod-matched electrophysiological responses were studied in isolated, arterially perfused cat eyes. 1. changes in glucose concentration in the perfusate induced remarkable effects in the electrical responses of retinal pigment epithelium neural retina, and optic nerve. 2. The ERG b-wave and the optic nerve response (ONR) were enhanced when glucose concentrations were increased above the standard level (5.5 mM), and were less than normal after termination of the increase in glucose, prior to recovery. 3. Decreasing glucose from the standard led to attenuation of b-wave and ONR. Both responses recovered completely upon returning to 5.5 mM glucose. 4. When the control perfusate contained higher glucose concentrations (8-10 mM), additional glucose failed to elicit significant effects on the b-wave and on the ONR. 5. Increasing glucose induced a small transient decrease in standing potential, followed by a marked and maintained increase. Decreasing glucose induced changes of similar magnitude but opposite polarity. 6. Supply of glucose to mammalian retina in vitro is crucial for optimal sensitivity as shown in rod-matched signals from the perfused cat retina.