Comparison of the binding of nicotinic agonists to receptors from human and rat cerebral cortex and from chick brain ( α 4β 2) transfected into mouse fibroblasts with ion channel activity

Abstract

(−)-Nicotine, cytisine and carbachol evoked 86Rb efflux from mouse fibroblasts stably transfected with α 4β 2 chick brain nicotinic subunits. This response to (−)-nicotine was inhibited by mecamylamine and dihydro-β-erythroidine and was mirrored by a rise in intracellular Ca 2+ measured by microspectrofluorimetry. Lobeline and isoarecolone methiodide evoked no significant 86Rb from cells and unlike the above agonists displayed significantly different IC 50 values for the displacement of [ 3H]nicotine from mammalian (rat and human cerebral cortex) and transfected fibroblast membranes.