Chapter 23 Neuropeptide Y receptor interaction with betaadrenoceptor coupling to adenylate cyclase

Abstract

Publisher Summary This chapter focuses on the receptor–receptor interactions studied by membrane fusion. One cell may have several receptors, which work through a common effector system. The receptors coupled to adenylate cyclase are the classic example. These receptors are known to have three components: (1) a molecule with a recognition site for a signal substance, the receptor component, (2) the guanine triphosphate (GTP)-binding protein (N-protein), the transducer, and (3) the catalytic unit (C), which is the enzyme adenylate cyclase, the effector. This system is sensitive to both positive and negative signals via functionally different transducers. To study potential receptor–receptor interactions in the adenylate cyclase system, the frontal cerebral cortex was chosen. This area has a dense representation of postsynaptic beta-adrenoceptors and of vasoactive intestinal polypeptide (VIP) receptors. Both noradrenaline (NA) and VIP receptor components couple via the stimulatory N s -protein to cyclase. VIP amplifies the activation of adenylate cyclase via beta-adrenoceptors in the slice preparations of cerebral cortex. Another peptide that occurs in large quantities in the central nervous system (CNS) and in the peripheral nervous system is neuropeptide Y (NPY). It is known to co-exist with NA in both. In the cerebral cortex, NPY is a major neuropeptide, although it is apparently not present in the NA neurons. Receptors for NPY have recently been identified in rat cerebral cortex membranes with the use of radioactive ligand binding techniques.