Fig. 4.

Light microscopic analysis of retinae of β2/β1^+/+ and β2/β1^ki/kimice. Semithin sections through retinae of 17-d-old (a–c), 4-month-old (d, e), and 9-month-old (f, g) β2/β1^+/+ (a, d, f), β2^−/− (c), and β2/β1^ki/ki (b, e, g) mice. Note that the thickness of the outer nuclear layer and the length of the inner and outer segments of photoreceptor cells is significantly reduced in 17-d-old β2^−/−(c) and 4-month-old β2/β1^ki/ki mice (e), and dramatically reduced in 9-month-old β2/β1^ki/kimutants when compared with age-matched wild-types (a, d, f). 1, Ganglion cell layer and nerve fiber layer; 2, inner plexiform layer; 3, inner nuclear layer; 4, outer plexiform layer;5, outer nuclear layer; 6, inner and outer segments of photoreceptor cells. Scale bar (shown inc for a–g): 100 μm.