Fig. 5.
Dark noise is mediated by transient receptor potential (TRP) channels. A: spontaneous dark noise was present in WT (left) and trp-like (trpl; right) photoreceptors but almost entirely absent in trp mutants (middle). B: high rate of dark noise seen in rdgA1/+ and ninaCP235 mutants (left) was abolished on trp mutant background (middle). Right: closer inspection of favorable recordings revealed infrequent residual dark bumps presumably mediated by TRPL channels. C: 80 μM La3+ (perfusion onset marked by arrowhead) rapidly suppressed dark noise in WT (n = 3) and rdgA1/+ (n = 2) photoreceptors, although some miniature dark bumps were retained. D: bar graph (means ± SE) for event rates (left) and bump amplitude (right) in trpl (n = 3; *no dark events were detected in trpl;trp double mutants), WT (n = 8), trp (n = 6), ninaCP235 (n = 19), ninaCP235;trp (n = 5), rdgA1/+ (n = 21), and rdgA1/+;trp (n = 4).