Journal of Neuroscience, Vol 6, 1199-1210, Copyright © 1986 by Society for Neuroscience
Dose-response analysis of effects of antibodies to large ganglion cells on the cat's retinogeniculate pathways
JW Crabtree, PD Spear, MA McCall, L Tong, KR Jones and SE Kornguth
Previous studies have shown that antibodies against large retinal ganglion
cells (alpha-/Y-cells) reduce the Y-cell retinogeniculate pathway while
having little or no effect on the X- or W-cell pathways. The present study
investigated the dose-response relationship of these effects. We began by
studying effects on the T1 (largely Y-cell- mediated) and T2 (largely
X-cell-mediated) waves of the retinal field- potential. Different
concentrations of the antibodies were injected intraocularly in adult cats
and retinal field-potentials evoked by optic chiasm stimulation were
examined. The lowest concentration of immune serum tested (330
micrograms/100 microliter volume) reduced both the T1 and T2 amplitudes.
With increasing concentrations, the ratio of T1:T2 amplitudes progressively
decreased from 0.71 to only 0.05. The highest concentration of immune serum
tested (1000 micrograms/100 microliter volume) virtually eliminated the T1
wave while the T2 wave remained (albeit reduced). Next, we carried out
single-cell physiological and morphological studies to verify the effects
of the highest antibody concentration and compare them with previous
results on effects of the lowest antibody concentration (Kornguth et al.,
1982; Spear et al., 1982). In single-cell recordings from the retina, the
encounter rates of Y- and X-cells were reduced by 85 and 53%, respectively,
after injection of the highest antibody concentration. There was no effect
on the encounter rate of retinal W-cells. After injection of the lowest
antibody concentration, there was no change in the encounter rates of any
of the retinal cell types. Morphological studies revealed an 88-99% loss of
alpha-cells in retinae treated with the highest antibody concentration.
There also was a substantial (24- 57%) loss of medium-size ganglion cells
but no loss of small ganglion cells. The loss of alpha-cells was much
greater after high- concentration injections than after low-concentration
injections. In recordings from the LGN, the proportion of Y-cells was
reduced by 87% in laminae receiving input from an eye injected with the
highest antibody concentration. Laminae receiving input from an eye
injected with the lowest concentration had a 77% reduction in Y-cells. The
encounter rate of LGN X-cells was not affected by either concentration.
Morphological analysis indicated that the loss of Y-cells in the LGN was
not due to changes in cell size. These findings indicate that
antibody-mediated effects on retinogeniculate pathways are dose-
dependent.(ABSTRACT TRUNCATED AT 400 WORDS)