Effects of barium on separately recorded fast and slow PIII responses in bullfrog retina

Summary Investigation of Ba²⁺ effects on fast and slow PIII responses in isolated bullfrog retina revealed that Ba²⁺ suppressed slow PIII completely with little effect on fast PIII. A light-induced [K⁺]₀ decrease in the photoreceptor layer was observed in spite of Ba²⁺ perfusion, indicating the suppressive action of Ba²⁺ on the K⁺ conductance of the Müller cell membrane.Acknowledgment. This work was supported by research grant from the Ministry of Education, Science and Culture of Japan and Kinki University research grant 55–103. The author wishes to thank Prof. I. Hanawa at Kobe University for his valuable discussions.