MOLECULAR REQUIREMENTS OF THE ACTIVE SITESOF THE CHOLINERGIC RECEPTORSXII (*) - 3-Methyl-2-oxo-L-dimethylaminomethylcyclopentane methiodideas a new selective agonist for the nicotinic receptorM. GIANNELLA, P. ANGELI, C. MELCHIORRE, L. BRASILI

To investigate further the nature of the active sites olcholinergic reeptors the carbocyclic analogs of isomuscarone and isomuscarine were synthesized- and tested for their cholinergicactivity.Like isomuscarines, such compounds are completely devoid of muscarinic activity which further support the hypothesis that the receptor site,corresponding to position 2 of the ring, cannot accept groups larger than and/or with a dipole having a different direction from that of an etheroxygen.on the other hand nicotinic activity is quite good. In this respectcompound (IV) is particulary interesting, being as actiie as ACh and pratically devoid of muscarinic aciivity.