Dopamine receptor D3

G-protein-coupled receptors, GPCRs, constitute a vast protein family that encompasses a wide range of functions (including various autocrine, paracrine and endocrine processes). They show considerable diversity at the sequence level, on the basis of which they can be separated into distinct groups. We use the term clan to describe the GPCRs, as they embrace a group of families for which there are indications of evolutionary relationship, but between which there is no statistically significant similarity in sequence . The currently known clan members include the rhodopsin-like GPCRs, the secretin-like GPCRs, the cAMP receptors, the fungal mating pheromone receptors, and the metabotropic glutamate receptor family. There is a specialized database for GPCRs: http://www.gpcr.org/7tm/.

The rhodopsin-like GPCRs themselves represent a widespread protein family that includes hormone, neurotransmitter and light receptors, all of which transduce extracellular signals through interaction with guanine nucleotide-binding (G) proteins. Although their activating ligands vary widely in structure and character, the amino acid sequences of the receptors are very similar and are believed to adopt a common structural framework comprising 7 transmembrane (TM) helices .

Neuropeptide Y (NPY) is one of the most abundant peptides in mammalian brain, inducing a variety of behavioural effects (e.g., stimulation of food intake, anxiety, facilitation of learning and memory, and regulation of the cardiovascular and neuroendocrine systems). In the periphery, NPY stimulates vascular smooth muscle contraction and modulates hormone secretion. NPY has been implicated in the pathophysiology of hypertension, congestive heart failure, affective disorders and appetite regulation .

G-protein-coupled receptors, GPCRs, constitute a vast protein family that encompasses a wide range of functions (including various autocrine, paracrine and endocrine processes). They show considerable diversity at the sequence level, on the basis of which they can be separated into distinct groups. We use the term clan to describe the GPCRs, as they embrace a group of families for which there are indications of evolutionary relationship, but between which there is no statistically significant similarity in sequence . The currently known clan members include the rhodopsin-like GPCRs, the secretin-like GPCRs, the cAMP receptors, the fungal mating pheromone receptors, and the metabotropic glutamate receptor family. There is a specialized database for GPCRs: http://www.gpcr.org/7tm/.

The rhodopsin-like GPCRs themselves represent a widespread protein family that includes hormone, neurotransmitter and light receptors, all of which transduce extracellular signals through interaction with guanine nucleotide-binding (G) proteins. Although their activating ligands vary widely in structure and character, the amino acid sequences of the receptors are very similar and are believed to adopt a common structural framework comprising 7 transmembrane (TM) helices .

In the periphery, the adrenergic system plays an important role in regulating the cardiovascular system . Increased sympathetic discharge to the heart increases the rate and force of contraction mediated through beta-1 receptors. Circulating adrenaline also acts on cardiac tissue, and, in addition, acts both on alpha-1 adrenoceptors in arterial smooth muscle, stimulating vasoconstriction, and on beta-2 adrenoceptors in vascular beds of skeletal muscle, stimulating vasodilation. In the CNS, noradrenaline is thought to be involved in the regulation of mood, and various psychoactive drugs alter noradrenergic function. Numerous drugs exert their actions via adrenoceptors: e.g., beta-2 selective agonists such as salbutamol are used in the acute treatment of asthma, while alpha agonists prolong the action of local anaesthetics, and act as nasal decongestants .

Adrenoceptors can be divided into three main classes based on sequence similarity, receptor pharmacology and signalling mechanisms. Further subdivisions exist within each class. A large number of agonists and antagonists distinguish between the different classes of adrenoceptor; by contrast, relatively small differences in agonist and antagonist affinities are demonstrated, especially within the alpha-1 and alpha-2 adrenoceptor subtypes .

G-protein-coupled receptors, GPCRs, constitute a vast protein family that encompasses a wide range of functions (including various autocrine, paracrine and endocrine processes). They show considerable diversity at the sequence level, on the basis of which they can be separated into distinct groups. We use the term clan to describe the GPCRs, as they embrace a group of families for which there are indications of evolutionary relationship, but between which there is no statistically significant similarity in sequence . The currently known clan members include the rhodopsin-like GPCRs, the secretin-like GPCRs, the cAMP receptors, the fungal mating pheromone receptors, and the metabotropic glutamate receptor family. There is a specialized database for GPCRs: http://www.gpcr.org/7tm/.

The rhodopsin-like GPCRs themselves represent a widespread protein family that includes hormone, neurotransmitter and light receptors, all of which transduce extracellular signals through interaction with guanine nucleotide-binding (G) proteins. Although their activating ligands vary widely in structure and character, the amino acid sequences of the receptors are very similar and are believed to adopt a common structural framework comprising 7 transmembrane (TM) helices .

G-protein-coupled receptors, GPCRs, constitute a vast protein family that encompasses a wide range of functions (including various autocrine, paracrine and endocrine processes). They show considerable diversity at the sequence level, on the basis of which they can be separated into distinct groups. We use the term clan to describe the GPCRs, as they embrace a group of families for which there are indications of evolutionary relationship, but between which there is no statistically significant similarity in sequence . The currently known clan members include the rhodopsin-like GPCRs, the secretin-like GPCRs, the cAMP receptors, the fungal mating pheromone receptors, and the metabotropic glutamate receptor family. There is a specialized database for GPCRs: http://www.gpcr.org/7tm/.

The rhodopsin-like GPCRs themselves represent a widespread protein family that includes hormone, neurotransmitter and light receptors, all of which transduce extracellular signals through interaction with guanine nucleotide-binding (G) proteins. Although their activating ligands vary widely in structure and character, the amino acid sequences of the receptors are very similar and are believed to adopt a common structural framework comprising 7 transmembrane (TM) helices .

Dopamine neurons in the vertebrate central nervous system are involved in the initiation and execution of movement, the maintenance of emotional stability, and the regulation of pituitary function . Various human neurological diseases (e.g., Parkinson disease and schizophrenia), are believed to be manifestations of dopamine and dopamine receptor imbalance. The receptors have been divided into several different subtypes, distinguished by their G-protein coupling, ligand specificity, anatomical distribution and physiological effects.

G-protein-coupled receptors, GPCRs, constitute a vast protein family that encompasses a wide range of functions (including various autocrine, paracrine and endocrine processes). They show considerable diversity at the sequence level, on the basis of which they can be separated into distinct groups. We use the term clan to describe the GPCRs, as they embrace a group of families for which there are indications of evolutionary relationship, but between which there is no statistically significant similarity in sequence . The currently known clan members include the rhodopsin-like GPCRs, the secretin-like GPCRs, the cAMP receptors, the fungal mating pheromone receptors, and the metabotropic glutamate receptor family. There is a specialized database for GPCRs: http://www.gpcr.org/7tm/.

The rhodopsin-like GPCRs themselves represent a widespread protein family that includes hormone, neurotransmitter and light receptors, all of which transduce extracellular signals through interaction with guanine nucleotide-binding (G) proteins. Although their activating ligands vary widely in structure and character, the amino acid sequences of the receptors are very similar and are believed to adopt a common structural framework comprising 7 transmembrane (TM) helices .

Dopamine neurons in the vertebrate central nervous system are involved in the initiation and execution of movement, the maintenance of emotional stability, and the regulation of pituitary function . Various human neurological diseases (e.g., Parkinson disease and schizophrenia), are believed to be manifestations of dopamine and dopamine receptor imbalance. The receptors have been divided into several different subtypes, distinguished by their G-protein coupling, ligand specificity, anatomical distribution and physiological effects.

D3 receptors have a similar pharmacological profile to D2 receptors. They are expressed predominantly in the limbic area (including the olfactory tubercle, nucleus accumbens, islands of Calleja and hypothalamus), and they are present in lower levels in the caudate-putamen and cerebral cortex. The receptors are also found in dopamine cell bodies in the substantia nigra. The distribution of the receptors is consistent with a role in cognition and emotional functions; they may thus be the target of antipsychotic therapy involving dopamine antagonists .