Different states of energy metabolism in the vertebrate retina can be identified by stimulus-related changes in near UV transmission.

BACKGROUND

Our aim was to identify different states of energy metabolism in the perfused isolated vertebrate retina by simultaneous recordings of light-evoked changes of transretinal potential (TRP) and spectroscopic changes related to oxidation of pyridine nucleotides.

METHODS

Isolated retinas were obtained from R.esc. and superfused. For each setting, three experiments were performed. Eighteen retinas were used. TRP as a response to light stimulation was recorded simultaneously with stimulus-induced transmission shift at 350 nm. These responses were recorded under normal conditions, under withdrawal of oxygen and glucose, and after addition of electron transport inhibitors and uncouplers of oxidative phosphorylation.

RESULTS

Under normal conditions, TRP was strongly correlated with transmission shift after light stimulation. Without oxygen, amplitudes of stimulus-related TRP decreased and response related increase of transmission at 350 nm was reduced. The retina showed a much higher general absorption of the analyzing light. During glucose lack, an overall increase in transmission at 350 nm could be observed. The addition of Amytal yielded a specific reduction of the OFF components. Cyanide attenuated the ON and OFF components. Dinitrophenol yielded a considerable loss of the electrical ON response. Transmission change was affected less than electrical signal. Chlorophenylhydrazine induced a reproducible reduction of electrical responses, with a relative increase of transmission shift at 350 nm.

CONCLUSION

In the isolated perfused retina, different states of energy metabolism and their specific impact on neuroretinal responses can be examined by simultaneous recordings of stimulus-related neuronal activity and spectroscopic changes.