Dopamine receptor alternative splicing

Abstract

The five dopamine receptor subtypes (D1-D5) are members of the superfamily of G protein-coupled receptors (see also Chapter 1). Dopamine receptors. have been known since 1978 to be divided between two families differing in biochemical and pharmacological properties (1). Although the G protein and second messenger systems affected by dopamine receptors in vivo have not been clearly established, in vitro D1-family receptors (D1 and D5) couple to Gs stimulatory proteins, activating adenylyl cyclase, whereas D2-family receptors (D2, D3, D4) couple to Gi inhibitory proteins, inhibiting adenylyl cyclase. Dopamine receptors couple effectively to a wide range of signaling cascades in vitro, including calcium channels, phospholipase C, potassium channels, arachidonic acid release, Na+/H+ exchangers, Na+-H+-ATPase, and cell growth and differentiation pathways (reviewed in ref. 2), suggesting that dopamine may mediate a complex array of neural signaling pathways in vivo. Dopamine systems are believed to exert functional effects through these second-messenger signaling pathways via modulation of the activity of more rapidly acting ionotropic glutamatergic, GABAergic, and nicotinic cholinergic neuronal systems (3). © 2005 Humana Press.