| Primary Identifier | IPR003907 | Type | Family |
| Short Name | GAL2_rcpt |
| description | Galanin is involved in a variety of physiological mechanisms and disease states, from appetite and neuroregeneration to seizures and pain [, ]. The actions of galanin are mediated through interaction with specific membrane receptors. Three receptor subtypes have been identified; Galanin receptor 1 (GALR1), Galanin receptor 2 (GALR2) and Galanin receptor 3 (GAL3), all of which are rhodopsin-like GPCRs. They differ from one another in terms of their expression patterns, affinity for various peptide analogues and G protein-coupling specificity [, , ]. In signaling, all can act via the Gi/o class [], whilst GAL2 also has Gq/11 as a major signaling route []. Galanin receptors are widely distributed in a wide range of central nervous system (CNS), peripheral tissues and in the endocrine, mirroring the distribution of galanin [, ]. Galanin receptors mediate a variety of physiological functions including inhibition of glucose-induced insulin secretion [], stimulation of growth hormone release []and modulation of gastrointestinal motility []. These receptors also modulate neuronal functions including memory, nociception, spinal reflexes and feeding [, ]. Disruption of galanin expression or galanin receptor signaling is seen in many multifactoral conditions, suggesting a role in the development and/or pathology of certain diseases. These include Alzheimer's disease, epilepsy, diabetes, alcoholism, neuropathic pain and cancer [, , ]. This entry represents the galanin receptor 2 subtype, which is expressed abundantly in both central and peripheral systems. In the brain, it has been found in the hypothalamus, amygdala, hippocampus, pyriform cortex, dendate gyrus, mammillary nuclei and cerebellar cortex []. Peripheral regions expressing the receptor include the prostate, uterus, ovary, vas deferens, stomach, intestine, dorsal root, pancreas, liver, heart and retina [, , ]. Activation of galanin receptor 2 leads to the stimulation of multiple intracellular events. The most commonly reported pathway appears to involve phospholipase C, because it mediates pertussis-toxin-resistant inositol phosphate hydrolysis [, , ], intracellular Ca2+ mobilisation []and Ca2+ dependent Cl- channel activation []. In addition, galanin receptor 2 can inhibit cAMP accumulation, depending on the host cell or the G-protein repertoire in the cell []. |
