Table 1.
Properties of electrical responses of PLC β4-null mice and wild-type controls
| Genotype | amax, μV | bmax, μV | rmax, pA | i0, photons/μm2 |
|---|---|---|---|---|
| +/+ | 320 ± 155 (4) | 790 ± 380 (4) | 8.9 ± 3.0 (11) | 60 ± 10 (10) |
| −/− | 77 ± 26 (5) | 168 ± 60 (5) | 8.9 ± 2.8 (96) | 50 ± 27 (77) |
amax and bmax denote the maximum amplitudes of the a-wave and the scotopic (rod-mediated) b-wave of the ERG, respectively. rmax is the amplitude of the maximal response determined by suction electrode recording from single rods (20, 21). i0 is the half-saturating flash strength, an inverse measure of rod flash sensitivity, obtained by fitting the relation between response amplitude and flash strength with the saturating exponential (r/rmax = 1 − exp(iln2/i0), where r is the response amplitude and i is the flash intensity in photons μm−2 at 500 nm. The number of photoisomerizations that gave a half-saturating response can be found by multiplying i0 by the rod collecting areas, ≈0.25 μm2. Error are SDs. Numbers in brackets give total animals for ERGs and total rods for photocurrents. The rods for photocurrents were from 3 PLC β4-null mice and 35 wild-type mice.