Disease relevance of Avp

• The localization of CRF-41 related peptide was studied in the brain and posterior pituitary of the homozygous rats for the inherited diabetes insipidus (Brattleboro strain, DI) and of the Long-Evans rats (LE) as control [1].
• BACKGROUND: Although, pharmacological intervention with a selective arginine vasopressin (AVP) V(2) receptor antagonist has been demonstrated to be effective for syndrome of inappropriate secretion of antidiuretic hormone (SIADH), its long-term administration has some therapeutic limitations [2].
• Studies were performed to determine the mechanism underlying deficient arginine vasopressin (AVP)-stimulated adenylyl cyclase activity in chronic renal failure (CRF) [3].
• These findings demonstrate that acute cholestasis in the rat is associated with suppression of hypothalamic-pituitary-adrenal axis responsiveness to stress and demonstrate a dissociation between mechanisms of ACTH regulation mediated by CRF and AVP [4].
• Plasma arginine vasopressin was also significantly higher in rats with cirrhosis (control = 1.77 +/- 0.16 and cirrhotic rats = 4.14 +/- 0.62 pg/ml, n = 9, p < 0.002) [5].

Psychiatry related information on Avp

• We hypothesized that ovarian steroids increase the onset of maternal behavior by a central mechanism involving OXY and possibly AVP [6].
• In rats, the basal levels of plasma AVP and OXT (means: 2.63 pg/ml and 6.80 pg/ml, respectively) are increased significantly after 24 h, 48 h and 72 h of water deprivation [7].
• During infusion of anti-AVP antibodies and dPTyr(Me)AVP and during the first days of recovery from AVP infusion, the ultradian rhythmic distribution of sleep and wakefulness was still present, but the amplitude of the circadian rhythm was reduced [8].
• Thus, variations in the magnitude of HPA responses to stress among males are explained in part by individual differences in circulating T levels, and the MPOA is a critical site for this effect via the inhibition of hypophysial AVP [9].
• In addition, coadministration of JTP-4819 and substance P, arginine-vasopressin or thyrotropin-releasing hormone (at doses at which each drug alone did not prolong the retention time) improved the retention time of rats with scopolamine-induced amnesia [10].

High impact information on Avp

• Long-term gene therapy in the CNS: reversal of hypothalamic diabetes insipidus in the Brattleboro rat by using an adenovirus expressing arginine vasopressin [11].
• The liver cDNA encodes a protein with seven putative transmembrane domains, which binds arginine vasopressin and related compounds with affinities similar to the native rat V1a receptor [12].
• The neurohypophyseal hormone arginine vasopressin has diverse actions, including the inhibition of diuresis, contraction of smooth muscle, stimulation of liver glycogenolysis and modulation of adrenocorticotropic hormone release from the pituitary [12].
• Arginine vasopressin receptors are G protein-coupled and have been divided into at least three types; the V1a (vascular/hepatic) and V1b (anterior pituitary) receptors which act through phosphatidylinositol hydrolysis to mobilize intracellular Ca2+, and the V2 (kidney) receptor which is coupled to adenylate cyclase [12].
• In mesangial cells, arginine vasopressin (AVP) raises pHi in the absence of HCO3-, but lowers it when HCO3- is present; growth is stimulated under both conditions [13].

Chemical compound and disease context of Avp

• CONCLUSIONS: Although the single effect of therapeutic dose of lithium was weak, it effectively and safely compensated for the therapeutic limitations of a low dose of AVP V(2) receptor antagonist for SIADH by reducing AQP2 expression [2].
• Whereas depletion of serotonin with p-chlorophenylalanine (PCPA) blocked the increase in hypothalamic levels of AVP and OT mRNA following osmotic stimuli in rats (2% saline drinking or dehydration), the increase in mRNA size was similar in PCPA and control animals [14].
• Blood values of arginine vasopressin and aldosterone were significantly increased by water deprivation, whereas they were unchanged by water overloading [15].
• Immunoreactive oxytocin and arginine vasopressin (AVP) were measured in the adrenal medulla of both rat and man as well as in tissue from two pheochromocytomas using highly specific RIAs [16].
• Like dVDAVP its antidiuretic effect in conscious diabetes insipidus rats is greatly prolonged when compared to AVP. dPVDAVP causes a prolonged inhibition of vasopressor responses to AVP but not to norepinephrine or angiotensin II [17].

Biological context of Avp

• Whereas steady state levels of OT mRNA were markedly increased throughout lactation, those of AVP mRNA were only transiently (initially) elevated, and the blood levels of these hormones were not significantly altered in lactating as compared with cycling virgin and postlactating rats [18].
• We hypothesize that the effects are mediated by rapid, direct vasodilation induced by CRH that decreases baroreceptor input to the brain stem, leading to a rapid release of AVP that induces the antidiuresis by direct action on the V(2)Rs in the kidney [19].
• AVP effectively inhibited [3H]AVP binding with an IC50 of 1.5 X 10(-7) M, while oxytocin showed a somewhat higher IC50 (0.9 X 10(-6) M) and did not achieve complete inhibition of binding [20].
• Our results show that the response of the AVP-eGFP fusion gene to chronic salt loading is exaggerated, and humoral responses such as AVP and OXT and the body fluid homeostasis are maintained in AVP-eGFP transgenic rats [21].
• Effects of rat corticotrophin-releasing factor, arginine vasopressin and oxytocin on the secretions of adrenocorticotrophic hormone and corticosterone in the fetal rat in late gestation: in vivo and in vitro studies [22].

Anatomical context of Avp

• Next, we demonstrated by simultaneous microdialysis of the suprachiasmatic nucleus and the PVN that AVP measured in PVN dialysates during social defeat was probably of intranuclear origin [23].
• In turn, releasable pools of CRH and AVP in neuroendocrine terminals are sustained by synthetic mechanisms in the medial parvicellular paraventricular nucleus, a critical component of which involves transcribing primary (heteronuclear (hn)) RNA transcripts from their cognate genes [24].
• Arginine vasopressin inhibits interleukin-1 beta-stimulated nitric oxide and cyclic guanosine monophosphate production via the V1 receptor in cultured rat vascular smooth muscle cells [25].
• Median eminence CRF and AVP content declined but OT content did not [26].
• Arginine vasopressin and corticotropin releasing factor: binding to ovine anterior pituitary membranes [27].

Associations of Avp with chemical compounds

• It is generally accepted that CRF stimulates activation of adenylate cyclase, whereas AVP activates phosphoinositidase in pituitary corticotropes [28].
• Other structurally unrelated peptides with intrinsic ACTH-releasing activity, such as rat corticotropin-releasing factor and angiotensin II, had no affinity for AVP-binding sites [20].
• Corticotropin-releasing hormone and arginine vasopressin gene transcription in the hypothalamic paraventricular nucleus of unstressed rats: daily rhythms and their interactions with corticosterone [24].
• However, even at 200 nM, the antipressor antagonists dPTyr(Me)AVP and d(CH2)5Tyr(Me)AVP had no effect on potentiation by AVP [29].
• Immunoreactive CRF, AVP, oxytocin and epinephrine were present in the portal plasma at concentrations within a range shown to evoke ACTH secretion from cultured pituitary cells when presented alone or in combination [30].

Physical interactions of Avp

• During atrial pulsation, a stimulus mimicking volume loading and associated with a reduction of systemic ACTH levels, we observed a significant decline in portal concentrations of immunoreactive AVP coupled with a nonsignificant trend toward reduced portal immunoreactive CRF levels [30].
• In addition to these differences in the regulation of biosynthesis and processing, AVP peptides were axonally transported to the pituitary 3 d earlier than OT peptides, and in far greater (20-fold) abundance [31].
• Arginine vasopressin interacts with the vasopressin type 1a receptor (V1aR) to initiate physiological effects such as vasoconstriction of blood vessels and glycogenolysis [32].
• The BK-receptor complex was not affected by angiotensin II or by arginine vasopressin and atrial natriuretic factor [33].

Enzymatic interactions of Avp

• These results strongly suggest that AVP phosphorylates HSP27 via p38 MAP kinase in aortic smooth muscle cells [34].

Co-localisations of Avp

• Moreover, AVP and AVP mRNA were found to be colocalized with oxytocin in a few neurons [35].

Regulatory relationships of Avp

• Antagonists for oxytocin ([des-glycinamide9,d(CH2)5(1),O-Me-Tyr2,Thr4,Orn8]vaso tocin), V2 ([d(CH2)5(1),D-Ile2,Ile4,Arg8]vasopressin), and V1a ([d(CH2)5(1),O-Me-Tyr2,Arg8]vasopressin) receptors partially inhibited the [Ca2+]i response induced by 10 nM AVP (89.5, 81.6, and 51.4% inhibition, respectively) [36].
• Arginine vasopressin stimulates phosphorylation of aquaporin-2 in rat renal tissue [37].
• CRF immunostainings were enhanced by colchicine treatment in LE rats and by DDAVP therapy in DI rats [1].
• RESULTS: AVP inhibited IL-1 beta-induced nitrite production in a dose- and time-dependent manner with concomitant changes in intracellular cGMP contents [25].
• To further specify the primary point of dysregulation of AQP channels that are activated by the arginine vasopressin/cyclic adenosine monophosphate (AVP/cAMP) pathway, different components of adenylyl cyclase complex were separately examined for their cAMP-generating activities [38].

Other interactions of Avp

• Recent studies have revealed that arginine vasopressin (AVP) has at least two types of receptors in the kidney: V1a receptor and V2 receptor [39].
• Thus AVP specifically increases nNOS expression levels in the renal outer medulla and papilla [40].
• AVP similarly reduced PRL increase induced by exposure to a novel environment stress [41].
• The aim of this study was to examine whether AVP, and other agents that increase cAMP levels, could stimulate the phosphorylation of AQP2 in intact rat renal tissue [37].
• CONCLUSIONS: The parallel dose-response curves for oxytocin and arginine vasopressin suggest that the uterotonic action of vasopressin is also mediated by the oxytocin receptor [42].

Analytical, diagnostic and therapeutic context of Avp

• To determine the fundamental daily patterns of ACTH secretagogue gene transcription in unstressed rats, we measured CRH and AVP hnRNA levels at 1- to 4-h intervals throughout the day using in situ hybridization [24].
• In addition, the identity of the HA-stimulated neurons was investigated by dual antigen immunohistochemistry visualizing AVP-, OT-, or CRH-IR in the neurons showing increased c-fos expression [43].
• Rats were either water restricted or water loaded to modify the circulating AVP levels, and expressions of NOS isoforms were assessed by Western blot analysis [40].
• Incubation of cells with AVP (1 nM to 3 microM) increased PGE2 synthesis measured by radioimmunoassay in a concentration-dependent fashion up to 2 1/2-fold over control; 1-desamino-8-D-arginine did not increase PGE2 synthesis [44].
• Systemic AVP-induced changes were maintained in hypophysectomized rats but were not observed after adrenalectomy [45].

References