Effects of retinal adhesion of temperature, cyclic AMP, cytochalasin, and enzymes

We have studied factors that contribute to retinal adhesion, by measuring directly the force required to peel rabbit retina from the retinal pigment epithelium (RPE). Exposing the tissue to either testicular hyaluronidase or neuraminidase, or acidifying the medium to pH 6.0, reduced the peeling force within 2 min. Cooling the tissue to 25 degrees C or 4 degrees C increased the peeling force to such a degree that retinal separation occurred by rupture of the RPE cells rather than widening of the subretinal space. Inhibition of the cytoplasmic contractile system with cytochalasin had no significant effect on peeling force, but dibutyryl cAMP (which decreases fluid absorption by the RPE) weakened adhesion. These results suggest that retinal adhesion involves a number of interrelated physical and metabolic factors.