| purpose: This study aims at investigating the changes in potassium channel functions and responses to potassium channel blockers in the epithelium of prostate of SD (sprague dawley) rats.Materials and Methods: Dorsolateral lobes of the prosates of 3-month-old and 12-month-old SD rats were romoved. The tissue was cut with scissors into small pieces(1-2mm3) and put into a phrosphate- buffered Ca2+-free Ringer's solution, and digested with collagenase IV for 25 min. After the digestion, the tissue chunks were moved to a fresh solution and gently agitated. Then the cells were cultured for one week. The potassium channel current of prostate epithelium were recorded using whole-cell voltage clamp.Results: At +80mv potential, the current density of 12-month-old rat group was (18.48±1.7) pA/pF (n=20, P<0.01), while the current density of 3-month-old rat group was (10.84±1.54) pA/pF (n=20, P<0.01). TEA(1mmol/l), potassium channel blocker, decreased peak current from 19.1±2.9 to 7.2±3.2. Ca2+-activated K current was decreased 63% in 12-month-old rats group. However, in the 3-month-old group, peak current was decreased 44% from 9.5±1.8 to 5.4±3.1.Potassium channel current of SD rat prostate epithelium was significantly blocked by 4-ap.Conclusions: potassium channel current are remarkably stronger in the 12-month-old rat group than in 3-month-old rat group, and the 12-month-old rat group were more sensitive to the channel blocker than that of the 3-month-old rat group. Increase in membrane potential promotes gland cell secretion. Aging is related to decreased gland cell secretion.
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