In vitro contraction of the pupillary sphincter by substance P and its stable analogs.
The effects of substance P and substance P analogs have been studied quantitatively by use of an isolated preparation of bovine pupillary sphincter muscle. Substance P contracts the pupillary sphincter in a dose-dependent manner with a value for median effective dose (ED50) of 1.0 X 10(-6) M. The effects of substance P result from its interaction with a specific receptor in the pupillary sphincter. These results strengthen the view that substance P is involved in the oculopupillary reflex.
D000818:Animals; D002417:Cattle; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D007498:Iris / Q000187:drug effects; D011680:Pupil / Q000187:drug effects*; D013373:Substance P / Q000031:analogs & derivatives / Q000494:pharmacology*
D013373:Substance P