A characterization of the effects of acetylcholine on the rabbit oviduct.

: The effect of acetylcholine (ACh) on the perfused oviduct of the rabbit was investigated. The response of the oviduct to ACh during early gestation was variable, i.e., biphasic (contraction followed by slight relaxation) greater than contractile greater than relaxation. The responsiveness of the oviduct to the contractile effect decreased progressively during early gestation, similar to that previously reported for norepinephrine (NE). The contraction produced by ACh was antagonized by chlorisondamine and atropine and also by phentolamine and pretreatment with reserpine. It was concluded that the response produced by ACh may be mediated in part through the release of NE.