KATP channels expressed in the neurosecretory cells of MTXO in the eyestalks of Eriocheir sinensis

Sensitivity to 0-1 mmol/L ATP of K_ATP channel in the neurosecretory cells of MTXO in the eyestalks of Eriocheir sinensis was observed with inside-out patch-clamp method and properties of K_ATP channels were studied with selective blocker and steroids. With symmetrical 200 mmol/L K⁺ on both sides of the excised membrane, the single-channel conductance was approximately 68 pS and the reversal potential was observed. These channels had a weak inward rectifying property. ATP applied inhibited channel activity in a concentration-dependent manner. The K_ATP currents can’t be reduced by depolarized stimulation when concentration of ATP is greater than 0.1 mmol/L. Moreover, opening activity of K_ATP was blocked when 1 mmol/L ATP was applied. The K_ATP channels were not obviously affected by cholesterol, but they were completely blocked by 0.1 mmol/L glybenclamide. The adenosine triphosphate-sensitive potassium channel, termed K_ATP channel, is characterized by a strong inhibition of channel activity by intracellular ATP thereby coupling the metabolic state of cells to their excitability and regulating a variety of functions. These results indicate that metabolic state of MTXO has feedback regulation on the secretion of neuropeptides hormone. Cholesterol can’t control secretion of eyestalks hormone by affecting K_ATP channels.