title: Interaction of guanidinium compounds and K+ channel modulators with imidazoline binding sites in rabbit kidney.
abstract: Several guanidinium compounds were tested for their ability to inhibit the binding of [3H]idazoxan to the I2 subtype of the imidazoline site on rabbit kidney basolateral membranes. Phenformin, a biguanide, was the most potent with an IC50 of 50 +/- 3 microM. Various K+ channel modulators were also evaluated for inhibition of [3H]idazoxan binding. 1,2,3,4-Tetrahydro-9-aminoacridine and 4-aminopyridine (IC50 values of 38 +/- 5 microM and 43 +/- 3 microM, respectively) were the most effective of the K+ channel blockers tested. Pinacidil, an ATP-sensitive K+ channel opener, inhibited radioligand binding with an IC50 of 100 +/- 10 microM. The results indicate that I2 sites are selective in their interaction with guanidinium derivatives and K+ channel modulators.
authors.affiliation: Department of Cardiovascular Diseases Research, G.D. Searle & Co., St. Louis, MO 63167.
authors.forename: V M
authors.initials: VM
authors.lastname: Corpus
authors.forename: S M
authors.initials: SM
authors.lastname: Bressie
authors.forename: L I
authors.initials: LI
authors.lastname: Stillwell
authors.forename: G M
authors.initials: GM
authors.lastname: Olins
mesh_terms: D000818:Animals; D001665:Binding Sites; D004146:Dioxanes / Q000378:metabolism / Q000494:pharmacology*; D004347:Drug Interactions; D019791:Guanidine; D006146:Guanidines / Q000494:pharmacology*; D019329:Idazoxan; D007093:Imidazoles / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism*; D008297:Male; D015221:Potassium Channels / Q000187:drug effects*; D011817:Rabbits
chemical_list: D004146:Dioxanes; D006146:Guanidines; D007093:Imidazoles; D015221:Potassium Channels; D019791:Guanidine; D019329:Idazoxan