title: A specific antiserum recognizes clonidine-displacing substance: implications for the structure of the brain's own clonidine.
abstract: A polyclonal antiserum was raised in rabbit against the clonidine analog p-aminoclonidine (PAC) coupled to hemocyanin. The antiserum (anti-PAC3) exhibited high affinity for unconjugated [3H]PAC (Kd 0.32 +/- 0.07 nM) in a rapid-filtration radioimmunoassay. Competition experiments showed that PAC, clonidine, and naphazoline cross-reacted with the anti-PAC3 antiserum, whereas a number of other structurally related compounds did not. An endogenous clonidine-displacing substance (CDS) partially purified from bovine brain also inhibited specific [3H]PAC binding to anti-PAC3 in a dose-dependent manner. Thus, (a) anti-PAC3 antiserum is specific for clonidine and closely related compounds, and (b) CDS may structurally resemble clonidine since it is recognized by this highly specific antiserum.
authors.affiliation: Division of Neurobiology, Cornell University Medical College, New York, NY 10021.
authors.forename: M P
authors.initials: MP
authors.lastname: Meeley
authors.forename: A C
authors.initials: AC
authors.lastname: Towle
authors.forename: P
authors.initials: P
authors.lastname: Ernsberger
authors.forename: D J
authors.initials: DJ
authors.lastname: Reis
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D002417:Cattle; D055598:Chemical Phenomena; D002621:Chemistry; D003000:Clonidine / Q000037:antagonists & inhibitors* / Q000276:immunology / Q000378:metabolism* / Q000031:analogs & derivatives; D003429:Cross Reactions; D007106:Immune Sera / Q000276:immunology*; D011863:Radioimmunoassay
chemical_list: D007106:Immune Sera; C055140:clonidine-displacing substance; D003000:Clonidine