Blue-sensitive rod input to bipolar and ganglion cells of the Xenopus retina.
Intracellular recordings were obtained from chromatic and non-chromatic bipolar cells, identified by Lucifer yellow injection in the Xenopus retina. The chromatic cells, which lacked center-surround organization, were short wavelength hyperpolarizing (lambda max 445 nm) and long wavelength depolarizing. Under photopic conditions the depolarizing component was driven by 612 nm cones, but under mesopic conditions it appeared that 524 nm rods also constituted an input to the response. The non-chromatic bipolars encountered were of the off-center (hyperpolarizing) variety, with an active antagonistic surround, and peak spectral sensitivity in the red portion of the spectrum. Extracellular recordings were obtained from color-coded ganglion cells classified as type 1 or 2 in frog retina by Maturana et al. (1966) [J. gen. Physiol. 43, 129-175] and Bäckström and Reuter (1975) [J. Physiol. 246, 79-107]. The spectral sensitivity of the long latency "on" component was matched by the density spectrum of the 445 nm rod. This response component lacked center-surround organization and showed a relatively broad area of spatial integration. In contrast, a short latency component had a spectral sensitivity matched by the 612 nm cone pigment under photopic conditions, was either "on" or "off" center, showed center-surround organization and had a relatively small area of spatial integration. We speculate that in Xenopus retina, both chromatic and non-chromatic bipolar cells provide synaptic input to the class 1,2 ganglion cell.
D000200:Action Potentials; D000221:Adaptation, Ocular; D000818:Animals; D005074:Evoked Potentials, Visual; D066298:In Vitro Techniques; D007546:Isoquinolines; D009474:Neurons / Q000502:physiology*; D010786:Photoreceptor Cells / Q000502:physiology*; D012160:Retina / Q000166:cytology*; D012165:Retinal Ganglion Cells / Q000502:physiology; D013053:Spectrophotometry; D014982:Xenopus laevis
D007546:Isoquinolines; C017475:lucifer yellow