TY - JOUR T1 - The Use of the Counter-Ion in Molecular Orbital Calculations of Histamine Conformations JF - Molecular Pharmacology JO - Mol Pharmacol SP - 663 LP - 666 VL - 11 IS - 5 AU - RAYMOND J. ABRAHAM AU - DENIS BIRCH Y1 - 1975/09/01 UR - http://molpharm.aspetjournals.org/content/11/5/663.abstract N2 - The introduction of the counter-ion into complete neglect of differential overlap (CNDO) calculations of the conformations of histamine dication and the two monocations produces results in good agreement with the observed conformations in aqueous solution. The significance of these results and their relationship to the "supermolecule" approach is discussed. ACKNOWLEDGMENTS We are most grateful to Dr. C. R. Ganellin for first drawing this problem to our attention and for his interest and encouragement, and to Professor and Mme Pullman for communicating their results prior to publication. ER -