Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Calcium ion plays a major regulatory role in many hormone-stimulated systems. To determine the site of calcium's action in the toad urinary bladder, we examined the effect of trifluoperazine, a compound that binds specifically to the calcium binding protein, calmodulin, and thereby prevents activation of enzymes by the calcium- calmodulin complex. 10 microM trifluoperazine inhibited vasopressin stimulation of water flow, but did not alter vasopressin's effects on urea permeability or short-circuit current. Trifluoperazine also blocked stimulation of water flow by cyclic AMP and methylisobutylxanthine, implying a "postcyclic AMP" site of action. Consistent with these results, trifluoperazine did not decrease epithelial cyclic AMP content or the cyclic AMP-dependent protein kinase activity ratio. Assay of bladder epithelial supernate demonstrated calmodulin-like activity of 1.5 U/microgram protein. Morphologic studies of vasopressin-treated bladders revealed that trifluoperazine did not alter the volume density of cytoplasmic microtubules or significantly decrease the number of fusions between cytoplasmic, aggregate-containing, elongated vesicles and the luminal membrane. Nonetheless, the frequency of luminal membrane aggregates, structures that correlate well with luminal membrane water permeability, was decreased by greater than 50%. Thus, trifluoperazine appears to inhibit the movement of intramembranous particle aggregates from the fused intracellular membranes to the luminal membrane, perhaps by blocking an effect of calcium on microfilament function.
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PMID:Effects of trifluoperazine on function and structure of toad urinary bladder. Role of calmodulin vasopressin-stimulation of water permeability. 625 6

Treatment with the calcium ionophore A23187 on either the serosal or mucosal sides of frog skin, strongly inhibits the hydrosmotic response to vasopressin. On the contrary, the hydrosmotic response to 8-br-cAMP is not affected by treatment with the A23187. Trifluoperazine, a drug which inhibits the Ca2+-calmodulin complex, selectively inhibits vasopressin-induced water transport. Collectively, our results suggest that an increase in the intracellular concentration of Ca2+, obtained by treatment with the ionophore A23187, interferes with a pre-cAMP step of the hydrosmotic response to the antidiuretic hormone. Calcium ions could regulate adenyl-cyclase activity and consequently intracellular levels of cAMP. This effect may probably involve calmodulin.
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PMID:Evidence for the role of calcium in the hydrosmotic response to antidiuretic hormone in frog skin. 644 24

The effects of trifluoperazine on the activation of glycogenolysis by various hormones were studied in perfused rat liver. Trifluoperazine significantly inhibited glycogenolytic effect of phenylephrine and angiotensin II by lowering maximal response, and that of vasopressin by shifting the dose-response curve to the right, while alpha-antagonist phentolamine was inhibitory only to phenylephrine. Phosphorylase activation of phenylephrine was inhibited by trifluoperazine in parallel with glycogenolytic response. The increase in 45Ca2+ efflux induced by phenylephrine, angiotensin II, and vasopressin was also inhibited by the agent. These inhibitory effects of trifluoperazine were not related to the change in tissue cyclic AMP or cyclic GMP levels. On the other hand, neither the glycogenolytic effect of glucagon, cyclic AMP, and N6,O2-dibutyryl cyclic AMP nor phosphorylase activation by glucagon was affected by trifluoperazine. Thus, trifluoperazine specifically inhibits the activation of glycogenolysis by Ca2+-dependent hormones.
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PMID:Inhibition by trifluoperazine of glycogenolytic effects of phenylephrine, vasopressin, and angiotensin II. 717 14

In continuation of our previous studies we have investigated some aspects of the hormonal control of glutamine metabolism in isolated rat hepatocytes. (1)Catecholamines, angiotensin II and vasopressin stimulate gluconeogenesis from glutamine more than 2-fold. These effects require the presence of Ca2+ in the incubation medium. (2) The phenothiazine, trifluoperazine, a purported specific inhibitor of calmodulin, completely blocks the stimulation by catecholamines without affecting the response to the other two hormones. (3) The effectiveness of trifluoperazine in preventing the stimulation of gluconeogenesis by catecholamines was dependent on the concentrations of both the hormones and the inhibitor. (4) Trifluoperazine, at concentrations that prevent stimulation by epinephrine of gluconeogenesis, was as effective as phentolamine in blocking the binding of [3H]epinephrine to intact hepatocytes. (5) These studies support the view (Blackmore, P.F., El-Refai, M.F., Dehaye, J.-P., Strickland, W.G., Haghes, B.P. and Exton, J.H. (1981) FEBS Lett. 123, 245--248) that inhibition by trifluoperazine of alpha-adrenergic stimuli does not necessarily mean that calmodulin is involved in post-receptor events.
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PMID:Effect of trifluoperazine on the stimulation by Ca2+-dependent hormones of gluconeogenesis from glutamine in isolated hepatocytes. 729 8

Possible involvement ofcalmodulin in adrenergic and serotoninergic regulation of vascular contractility has been studied. Calmodulin inhibitors trifluoperazine and W-13 suppress vasoconstriction of the rat aorta in response to norepinephrine, serotonin, and serotonin 5HT1A- and 5HT2A-receptor agonists (8-OH-DPAT and DOI, respectively) and do not affect the vasodilatory effect of 5HT1B-, 5HT2B-, and 5HT4-receptors. The force of aorta contraction in response to 8-OH-DPAT increases after the activation of calcium entry through voltage-gated Ca2+-channels. This effect is not related to non-specific activation of alpha1-adrenoceptors, since it is realized in the presence of prazosin. The inhibitor of calmodulin-dependent myosin light chain kinase KN93 decreases the vasoconstrictive response in response to norepinephrine and serotonin by only 20%. Calmodulin inhibitors slightly decrease aortic constriction in response to endothelin-1, vasopressin, angiotensin II, and KCl. Trifluoperazine does not suppress vasoconstriction induced by the G-protein activator AlF4(-). It is assumed that the target of trifluoperazine and W-13 is calmodulin interacting directly with alpha1-adrenoceptors and serotonin 5HT1A- and 5HT2A-receptors.
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PMID:[Involvement of calmodulin in realization of vasoconstrictive effects of serotonin and norepinephrin]. 2298 60

We investigated the role of 5HT2C receptors in regulation of blood vessel contractility. We determined expression of 5HT2C receptors in smooth muscle cell line A7r5 as well as on isolated rat aorta. It was shown that strong vasoconstriction effect of 5HT2C receptor agonists - SCH 23390 and MK 212 appeared on blood vessels after preliminary activation of angiotensin ATIA- and vasopressin V1A-receptors. Biphasic contraction (a rhythmic alternation of contraction and subsequent relaxation phases of aoitic rings) and tonic contraction were observed in 75% and 25% of the cases after 5HT2C receptor activation, respectively. Periodic high amplitude constrictions of isolated rat aorta, induced by SCH 23390 and MK 212 agonists, were persisted for a long time (>1 hour). It was revealed that calmodulin and c-Src kinase play a central role in the mechanisms of signal transduction from 5HT2C receptors. Trifluoperazine and PP2, the inhibitors of calmodulin and c-Src kinase, respectively, abolished vasoconstriction reaction of isolated aortic rings in response to SCH 23390 and MK 212 but did not affect the strength gain of the vasoconstriction caused by fluoroaluminate, a G-protein activator. Taken together, these date suggest that 5HT2C receptors are in a latent state in blood vessels (<<silent>> receptors) and activation of these receptors is dependent on the functional state of the receptors of other endogenous vasoconstrictors.
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PMID:[Agonists of 5HT2C-receptors SCH 23390 and MK 212 incresase the force of rat aorta contraction in the presence of vasopressin and angiotensin II]. 2598 Feb 23