title: Homologous and heterologous acute desensitization of vasopressin V1a receptor in Xenopus oocytes.
abstract: The mechanism of short-term desensitisation of the V1a vasopressin receptor, a phospholipase-C beta linked receptor, was investigated in albino Xenopus oocytes. V1a receptors showed rapid agonist-dependent mobilisation of intracellular calcium, as detected by aequorin photon emission. Agonist-induced homologous short-term desensitisation was evidenced within minutes after stimulation. Injection of the second messengers calcium or inositol triphosphate inside the cell did not desensitise the receptors. In contrast, protein kinase C (PKC) activators 1-oleoyl-2-acetyl-sn-glycerol (OAG) (50 microM) and 1,2-dioctanoyl-glycerol (DIC8) (10 microM), as well as phorbol -12-myristate-13-acetate (1 microM) and phorbol -12,13-dibutyrate (1 microM) blunted the calcium responsiveness of the V1a receptors. The specific PKC inhibitor bisindolylmaleimide (GF109203X) (1 microM) prevented the effect of DIC8 and OAG on V1a receptor desensitisation. Heterologous desensitisation induced by agonist occurred in oocytes that co-expressed the V1a receptor and the PKC-activating M5 muscarinic receptor. It was concluded that PKC activation has a role in short-term desensitisation of the V1a receptor.
authors.affiliation: Départment de Biologie Cellulaire et Moléculaire, CEA Saclay, Gif-sur-Yvette, France.
authors.forename: N
authors.initials: N
authors.lastname: Ancellin
authors.forename: A
authors.initials: A
authors.lastname: Morel
mesh_terms: D000331:Aequorin; D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists; D001127:Arginine Vasopressin / Q000031:analogs & derivatives / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002122:Calcium Chloride / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D004075:Diglycerides / Q000494:pharmacology; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D007295:Inositol Phosphates / Q000494:pharmacology; D007527:Isoenzymes / Q000378:metabolism; D008301:Maleimides / Q000494:pharmacology; D018721:Muscarinic Agonists / Q000494:pharmacology; D009865:Oocytes; D010703:Phorbol Esters / Q000494:pharmacology; D054799:Phospholipase C beta; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D011976:Receptors, Muscarinic / Q000235:genetics / Q000502:physiology; D017483:Receptors, Vasopressin / Q000235:genetics / Q000502:physiology*; D015290:Second Messenger Systems; D010738:Type C Phospholipases / Q000378:metabolism; D014982:Xenopus laevis
chemical_list: D065092:Antidiuretic Hormone Receptor Antagonists; D004075:Diglycerides; D004791:Enzyme Inhibitors; D007211:Indoles; D007295:Inositol Phosphates; D007527:Isoenzymes; D008301:Maleimides; D018721:Muscarinic Agonists; D010703:Phorbol Esters; D011976:Receptors, Muscarinic; D017483:Receptors, Vasopressin; C044295:1,2-dioctanoylglycerol; D001127:Arginine Vasopressin; D000331:Aequorin; C038237:1-oleoyl-2-acetylglycerol; D002217:Carbachol; D011493:Protein Kinase C; D010738:Type C Phospholipases; D054799:Phospholipase C beta; D002122:Calcium Chloride; C088060:bisindolylmaleimide; D002118:Calcium