part Part I Screening of Ligands for GPCRs -- chapter 1 Screening of Endogenous Ligands for Orphan GPCRs / chapter 2 Screening of Ligands for Human GPCRs by the Use of Receptor-Gα Fusion Proteins / chapter 3 Screening and Identification of Ghrelin, an Endogenous Ligand for GHS-R / chapter 4 Ligand Screening of Olfactory Receptors / part Part II Functions and Regulations of GPCRs -- chapter 5 Generation and Phenotypical Analysis of Muscarinic Acetylcholine Receptor Knockout Mice / chapter 6 Systematic Mutagenesis of M Muscarinic Acetylcholine Receptors / chapter 7 Analysis of the Regulation of Muscarinic Acetylcholine Receptors / chapter 8 Single-Molecule Analysis of Chemotactic Signaling Mediated by cAMP Receptor on Living Cells / chapter 9 Oligomerization of G Protein-Coupled Purinergic Receptors / part Part III Tertiary Structure of GPCRs and Their Ligands -- chapter 10 Methods and Results in X-Ray Crystallography of Bovine Rhodopsin / chapter 11 Determination of Steric Structure of Muscarinic Ligands Bound to Muscarinic Acetylcholine Receptors: Approaches by TRNOE (Transferred Nuclear Overhauser Effect) -- chapter 12 Modeling of G Protein-Coupled Receptors for Drug Design