Hanitzsch R, Küppers L
Carl-Ludwig-Institute of Physiology, University of Leipzig, Liebigstr. 27, D-04103 Leipzig, Germany.
Vision Res. 2001 Aug;41(17):2165-72. doi: 10.1016/s0042-6989(01)00116-x.
HEPES-buffered solutions, mostly used in studies of isolated cells, and bicarbonate-buffered solutions, mostly used in studies of isolated retinal tissues, have both been used to superfuse an isolated rabbit retina preparation. The responses of horizontal cells (HCs) to light, detected by intracellular microelectrodes filled with Lucifer Yellow, were recorded. Buffering of the superfusate with 100% HEPES completely, but reversibly, abolished the responses of A-type HCs, and is not, therefore, suitable for studies on isolated rabbit retinas. The responses remained when buffering was partially with HEPES and partially with bicarbonate, but were changed: in A-type HCs the overshoot was reduced and the afterpotential was increased. The overshoot may be caused by feedback of HCs on the cones and might be dependent on pHi at the synaptic structure between HCs and photoreceptors.
HEPES缓冲溶液主要用于分离细胞的研究，而碳酸氢盐缓冲溶液主要用于分离视网膜组织的研究，这两种溶液都已被用于对分离的兔视网膜标本进行灌流。用充满荧光黄的细胞内微电极检测水平细胞（HCs）对光的反应并进行记录。用100%的HEPES对灌流液进行缓冲可完全但可逆地消除A型HCs的反应，因此不适合用于兔视网膜分离标本的研究。当灌流液部分用HEPES缓冲、部分用碳酸氢盐缓冲时，反应仍然存在，但发生了变化：在A型HCs中，超射减少，后电位增加。超射可能是由HCs对视锥细胞的反馈引起的，可能取决于HCs与光感受器之间突触结构处的细胞内pH值。
