Receptor for L-alpha-lysophosphatidylinositol (LPI). LPI induces Ca(2+) release from intracellular stores via the heterotrimeric G protein GNA13 and RHOA (By similarity). Putative cannabinoid receptor (By similarity). May play a role in bone physiology by regulating osteoclast number and function (By similarity). May be involved in hyperalgesia associated with inflammatory and neuropathic pain. Mutant mice are resistant to mechanical hyperalgesia and have increased levels of anti-inflammatory cytokines. The classification of this protein as a cannabinoid receptor remains a contentious issue due to conflicting pharmacological results. Belongs to the G-protein coupled receptor 1 family.