Electrical parameters of the isolated monkey ciliary epithelium and effects of pharmacological agents

The electrical properties of the isolated monkey ciliary epithelium (CE) were determined in an Ussing-type chamber. In a Hepes, HCO3- buffered solution, transepithelial potential difference (PD), short-circuit current (SCC) and electrical resistance (Rt) were -2.5 mV (aqueous-side negative), 8.5 microA and 246 omega, respectively. Epinephrine (0.01 mM) increased the SCC and PD across the isolated monkey CE when added to the aqueous-side bathing solution but was without effect when added to the blood-side bathing solution. Forskolin (0.01 mM) increased the SCC and PD when added to the bathing solution on either side. A disulfonic stilbene, DIDS (0.1 mM), reduced the SCC and PD when added to the aqueous-side bathing solution but was without effect when added to the blood-side bathing solution. Ouabain (0.1 mM) added to the aqueous-side produced a transient stimulation followed by a gradual inhibition of the SCC and PD. On the blood-side, ouabain directly inhibited the SCC and PD towards zero. Although the general electrical properties were similar to those of the isolated rabbit iris-ciliary epithelium, there were differences in the effects of these pharmacological agents on the electrical properties.