Fig. 2.
Vasopressin 1a receptor binding in the presence and absence of a selective receptor antagonist. (A) Incubation with the radioligand [125I]-phenylacetyl-D-Tyr(Me)-Phe-Gln-Asn-Arg-Pro-Arg-Tyr-NH2. (B) Co-incubation with radioligand and an excess of unlabeled selective vasopressin 1a receptor ligand d(CH2)51[Tyr(Me)2,Arg8]vasopressin in an adjacent section from the same brain. Exposure time was optimized to keep lateral septum binding within the linear range of iodinated standards; in this range non-specific binding was almost undetectable.