GPR18 receptor ­ the structure and the role in the physiology and pathophysiology / Receptor GPR18 ­ struktura i rola w fizjologii oraz patofizjologii.

G-protein coupled receptors constitute the largest family of membrane receptors and they participate in the maintenance of the homeostasis in the body. Some of these receptors still remain orphan receptors as there is insufficient research and ambiguous evidence concerning their function and endogenous ligands. For a long time, GPR18 belonged to this group, but recently it has been classified as an endocannabinoid receptor due to its affinity to cannabinoid ligands. GPR18 receptor is expressed in the encephalon, thyroid gland, leukocytes, lungs and testicles. The modulatory role of GPR18 receptor has been proven in the regulation of intraocular pressure, neuroimmunomodulation, regulation of arterial blood pressure and in metabolic disorders. In this article we summarize the current knowledge concerning the GPR18 receptor ­ its expression, ligands and the in the physiological processes and the pathophysiological conditions.