Altered resting membrane potential in the supersensitive vas deferens of the guinea pig

Microelectrodes have been used to obtain evidence for cellular changes associated with postjunctional supersensitivity in the vas deferens. Chronic decentralization or denervation caused a partial depolarization. A study of the time course of this depolarization in decentralized vasa deferentia indicated that the phenomenon appeared and reached a plateau between the 2nd and 4th postoperative day, i. e., at the same time as postjunctional supersensitivity develops in this tissue. Junction potentials induced by transmural stimulation and measured in impaled cells were not significantly different in control and decentralized cells. The results are discussed in relation to existing theories of supersensitivity and information in the literature regarding other cellular changes, especially of calcium. It is hypothesized that postjunctional supersensitivity is due, at least in part, to a reduction in resting membrane potential associated with a decrease in calcium bound to the cell membrane.