This is an application to fund a 4 1/2 day international conference, to be held in the United States, in the Fall of 1983. The central focus of the conference will be the presentation, discussion and consolidation of up-to-date information regarding the function of cholinergic mechanisms in health, disease, and aging. This will be the fifth in a series of similar conferences. Such conferences have been convened approximately every three years, each time under the organization and coordination of a different host, assisted by an international scientific committee consisting of individuals with acknowledged expertise in the cholinergic system. Detailed information regarding the content, and participants in the earlier conferences is provided in this application, in the form of Appendix I. In the present conference, facets of the cholinergic system which are of considerable practical relevance today will be highlighted. Seven key topics have been identified by the scientific committee, and these will serve as focal points for the program (see details in B.12.). Of course, other topics of concern will not be excluded, and all efforts will be made to develop a well balanced and scientifically stimulating program. The mechanism by which we propose to do this is outlined in detail within this application. Although, initially, research on cholinergic mechanisms lagged behind investigations pertaining to other key neurotransmitter systems, the past decade has witnessed a resurgence of interest in factors involving cholinergic phenomena. This conference will serve to highlight new developments and discoveries in the area; possibly resolve some discrepancies and controversies in the field; and hopefully stimulate and generate new ideas for further research into factors pertaining to cholinergic mechanisms in health, disease and aging.