Pituitary adenylate cyclase-activating polypeptide type I receptor also known as PAC1, is a protein that in humans is encoded by the ADCYAP1R1 gene. [5] This receptor binds pituitary adenylate cyclase activating peptide. [6] [7]
Pituitary adenylate cyclase-activating polypeptide type I receptor also known as PAC1, is a protein that in humans is encoded by the ADCYAP1R1 gene. [5] This receptor binds pituitary adenylate cyclase activating peptide. [6] [7]
PAC1 is a membrane-associated protein and shares significant homology with members of the G-protein coupled class B glucagon/secretin receptor family. [8] This receptor mediates diverse biological actions of adenylate cyclase activating polypeptide 1 and is positively coupled to adenylate cyclase. Alternative splicing of two exons of this gene generates four major splice variants, but their full-length nature has not been determined. [5] PAC1 is expressed in the adrenal medulla, pancreatic acini, uterus, myenteric plexus and brain. [9] [10] [11] It is also expressed in the trigeminal, otic and superior cervical ganglia (prejunctional) and cerebral arteries (postjunctional). [12]
Secretin is a hormone that regulates water homeostasis throughout the body and influences the environment of the duodenum by regulating secretions in the stomach, pancreas, and liver. It is a peptide hormone produced in the S cells of the duodenum, which are located in the intestinal glands. In humans, the secretin peptide is encoded by the SCT gene.
Corticotropes are basophilic cells in the anterior pituitary that produce pro-opiomelanocortin (POMC) which undergoes cleavage to adrenocorticotropin (ACTH), β-lipotropin (β-LPH), and melanocyte-stimulating hormone (MSH). These cells are stimulated by corticotropin releasing hormone (CRH) and make up 15–20% of the cells in the anterior pituitary. The release of ACTH from the corticotropic cells is controlled by CRH, which is formed in the cell bodies of parvocellular neurosecretory cells within the paraventricular nucleus of the hypothalamus and passes to the corticotropes in the anterior pituitary via the hypophyseal portal system. Adrenocorticotropin hormone stimulates the adrenal cortex to release glucocorticoids and plays an important role in the stress response.
Vasoactive intestinal peptide, also known as vasoactive intestinal polypeptide or VIP, is a peptide hormone that is vasoactive in the intestine. VIP is a peptide of 28 amino acid residues that belongs to a glucagon/secretin superfamily, the ligand of class II G protein–coupled receptors. VIP is produced in many tissues of vertebrates including the gut, pancreas, cortex, and suprachiasmatic nuclei of the hypothalamus in the brain. VIP stimulates contractility in the heart, causes vasodilation, increases glycogenolysis, lowers arterial blood pressure and relaxes the smooth muscle of trachea, stomach and gallbladder. In humans, the vasoactive intestinal peptide is encoded by the VIP gene.
The glucagon receptor is a 62 kDa protein that is activated by glucagon and is a member of the class B G-protein coupled family of receptors, coupled to G alpha i, Gs and to a lesser extent G alpha q. Stimulation of the receptor results in the activation of adenylate cyclase and phospholipase C and in increased levels of the secondary messengers intracellular cAMP and calcium. In humans, the glucagon receptor is encoded by the GCGR gene.
There are two known receptors for the vasoactive intestinal peptide (VIP) termed VPAC1 and VPAC2. These receptors bind both VIP and pituitary adenylate cyclase-activating polypeptide (PACAP) to some degree. Both receptors are members of the 7 transmembrane G protein-coupled receptor family.
Pituitary adenylate cyclase-activating polypeptide also known as PACAP is a protein that in humans is encoded by the ADCYAP1 gene. pituitary adenylate cyclase-activating polypeptide is similar to vasoactive intestinal peptide. One of its effects is to stimulate enterochromaffin-like cells. It binds to vasoactive intestinal peptide receptor and to the pituitary adenylate cyclase-activating polypeptide receptor.
The secretin receptor is a protein that in humans is encoded by the SCTR gene. This protein is a G protein-coupled receptor which binds secretin and is the leading member of the secretin receptor family, also called class B GPCR subfamily.
Urotensin-II (U-II) is a peptide ligand that is the strongest known vasoconstrictor. Because of the involvement of the UII system in multiple biological systems such as the cardiovascular, nervous, endocrine, and renal, it represents a promising target for the development of new drugs.
The gastrin-releasing peptide receptor (GRPR), now properly known as BB2 is a G protein-coupled receptor whose endogenous ligand is gastrin releasing peptide. In humans it is highly expressed in the pancreas and is also expressed in the stomach, adrenal cortex and brain.
The growth-hormone-releasing hormone receptor (GHRHR) is a G-protein-coupled receptor that binds growth hormone-releasing hormone. The GHRHR activates a Gs protein that causes a cascade of cAMP via adenylate cyclase. GHRHR is distinct from the growth hormone secretagogue receptor, where growth hormone releasing peptides act to release growth hormone.
The prolactin-releasing peptide receptor (PrRPR) also known as G-protein coupled receptor 10 (GPR10) is a protein that in humans is encoded by the PRLHR gene.
Corticotropin-releasing hormone receptor 2 (CRHR2) is a protein, also known by the IUPHAR-recommended name CRF2, that is encoded by the CRHR2 gene and occurs on the surfaces of some mammalian cells. CRF2 receptors are type 2 G protein-coupled receptors for corticotropin-releasing hormone (CRH) that are resident in the plasma membranes of hormone-sensitive cells. CRH, a peptide of 41 amino acids synthesized in the hypothalamus, is the principal neuroregulator of the hypothalamic-pituitary-adrenal axis, signaling via guanine nucleotide-binding proteins (G proteins) and downstream effectors such as adenylate cyclase. The CRF2 receptor is a multi-pass membrane protein with a transmembrane domain composed of seven helices arranged in a V-shape. CRF2 receptors are activated by two structurally similar peptides, urocortin II, and urocortin III, as well as CRH.
Vasoactive intestinal peptide receptor 2 also known as VPAC2, is a G-protein coupled receptor that in humans is encoded by the VIPR2 gene.
G-protein coupled receptor 3 is a protein that in humans is encoded by the GPR3 gene. The protein encoded by this gene is a member of the G protein-coupled receptor family of transmembrane receptors and is involved in signal transduction.
Vasoactive intestinal polypeptide receptor 1 also known as VPAC1, is a protein, that in humans is encoded by the VIPR1 gene. VPAC1 is expressed in the brain (cerebral cortex, hippocampus, amygdala), lung, prostate, peripheral blood leukocytes, liver, small intestine, heart, spleen, placenta, kidney, thymus and testis.
Secretin receptor family consists of secretin receptors regulated by peptide hormones from the glucagon hormone family. The family is different from adhesion G protein-coupled receptors.
Adenylyl cyclase type 6 is an enzyme that in humans is encoded by the ADCY6 gene.
Adenylyl cyclase type 4 is an enzyme that in humans is encoded by the ADCY4 gene.
Prolactin-releasing peptide (PrRP) is a peptide hormone that in humans is encoded by the PRLH gene. PrRP stimulates prolactin (PRL) release and regulates the expression of prolactin through binding to the prolactin-releasing peptide receptor (GPR10).
Philip Lazarovici is a neuropharmacologist at the Hebrew University of Jerusalem and a member of the Institute of Drug Research of the School of Pharmacy.
This article incorporates text from the United States National Library of Medicine, which is in the public domain.