Objective To establish an acupoint-connective tissue model for studying the mechanism of acupuncture by using in vitro patch clamp technique in the rat skin slices.Methods The local connective tissue under the corium of "Housanli"(ST 36) area from SD rat was acutely and bluntly separated and fixed in a chamber filled with artificial incubation solution.Mast cells in the prepared connective tissue slice were labeled by toluidine blue(TB) or neutral red(NR).The whole-cell current of mast cells responding to pressure stimulation applied through a patch pipette was recorded in rat slices derived from acupoint ST 36 area by using in vitro patch-clamp technique.Results 1) After staining with TB and NR

the labeled mast cells were found to distribute in the extracellular matrix of the connective tissue samples

and their degranulation phenomenon could be seen clearly.2) The whole-cell current of mast cells in response to mechanical stress stimulation was successfully recorded in the connective tissue slices of the rat acupoint ST 36 area.The cellular membrane currents increased evidently when pressure gradients of-30

-60 or-90 cmH2O were applied to the recorded mast cells.Conclusion The connective tissue slice from the rat ST 36 area may be used as a model for investigating the peripheral mechanism of acupuncture by combining the microtechniques and electrophysiological techniques.The results obtained in this model prove for the first time by electrophysiology that the mast cells in the connective tissue are probably involved in the transduction process of the mechanical signal from acupuncture stimulation.This new model provides a base for investigating the characters of the cells

collagen fibers

proteoglycans

etc.and their interactions in the acupoint connective tissue in the future.