EC:2.7.11.13 - FACTA Search

Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.13 (protein kinase C)
49,245 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The suprachiasmatic nucleus (SCN) is the locus of the main pacemaker for circadian behavioral rhythms. In common voles, variation in circadian behavioral rhythmicity correlates with vasopressin (AVP) immunoreactive cells in the SCN. Here we studied the immunostaining of four AVP linked Ca(2+)-dependent protein kinase C (PKC) isoforms (PKCalpha, PKCbeta1, PKCbeta2, and PKCgamma) at the beginning of the light period, and conclude that PKCalpha is highly expressed in the vole SCN compared to the other isozymes. Voles, characterized as strongly circadian rhythmic showed circadian variation in numbers of PKCalpha immunoreactive SCN neurons, while voles with weak or no circadian rhythmicity did not reveal such a circadian profile. PKCalpha immunoreactivity in acute SCN slices that were treated with a physiological dose of AVP was significantly lowered when compared with control slices. The intracellular messenger PKCalpha may reflect variation in locomotor behavior via the AVP system in the vole SCN. This system could play a key role in the vole SCN by mediating output of its circadian clock.
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PMID:Not only vasopressin, but also the intracellular messenger protein kinase Calpha in the suprachiasmatic nucleus correlates with expression of circadian rhythmicity in voles. 1263 37

Previous in vivo studies in cardiomyopathic hamsters suggested that the expression of vasopressin (AVP) V2 mRNA is up- regulated by angiotensin II. The present study was performed to determine whether angiotensin II plays a role in regulating the expression of AVP V2 mRNA and aquaporin-2 (AQP2) mRNA in the inner medullary collecting duct (IMCD) of the male Wistar rat. The expression of AVP V2 mRNA and AQP2 mRNA in the IMCD was measured by competitive reverse-transcriptase polymerase chain reaction (RT-PCR). Six groups of experiments were performed. In the first group, we incubated IMCD with 3 different doses of angiotensin II (10(-11), 10(-9) and 10(-7) mol/L). Angiotensin II caused a significant increase in the AVP V2 mRNA in a dose-dependent manner but its effect on AQP2 mRNA was modest. This effect of angiotensin II was inhibited by angiotensin II receptor antagonist, [Sar1,Ile8]-angiotensin II. To examine the role of PKA in mediating an increase in AVP V2 mRNA expression, we incubated IMCD with 10(-7) and 10(-11) M of angiotensin II in the presence of a specific protein kinase A (PKA) inhibitor, Rp diasteroisomer of adenosine 3'-5'-cylic monophosphothionate (Rp-cAMPS). The angiotensin II-induced upregulation of V2 mRNA was abolished. In the fourth group, we examined the effect of protein kinase C (PKC) inhibition on V2 mRNA expression. The upregulation of V2 mRNA induced by angiotensin II was greatly exaggerated when IMCD was incubated with angiotensin II and RO-31-8220 (PKC inhibitor). In the fifth and sixth groups of studies, we determined the direct effect of PKA and PKC on regulating the expression of V2 mRNA and AQP2 mRNA in the IMCD, respectively. Dibutryl cAMP stimulated an upregulation in the expression of V2 mRNA and AQP2 mRNA, whereas phorbol esters suppressed the expression of V2 mRNA. These results suggested that PKA stimulates and PKC suppresses the expression of V2 mRNA in the IMCD of the kidney.
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PMID:Angiotensin II upregulates the expression of vasopressin V2 mRNA in the inner medullary collecting duct of the rat. 1264 65

In order to determine the mechanism of action of a new AVP(4-9) analog, NC-1900, on memory processes, memory retention and retrieval tests were conducted in a step-through passive avoidance (PA) task in mice. The administration of NC-1900 facilitated memory retention and retrieval in the PA task through vasopressin1A (V1A) receptors but not V2 receptors. The effect of NC-1900 on memory retention test performance appeared to be due to activation of the protein kinase C (PKC) signaling pathway via V1A receptors; however, the modulation of PKC was not essential for the facilitative effect of the new peptide in the retrieval test. The facilitation of memory retrieval by NC-1900 may also be mediated by other non-PKC-dependent signaling pathways, such as the phospholipase C-inositol trisphosphate pathway.
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PMID:Facilitative effect of a novel AVP fragment analog, NC-1900, on memory retention and recall in mice. 1524 73

In the renal collecting duct (CD), water reabsorption depends on the presence of aquaporin-2 (AQP2) in the apical membrane of principal cells. AQP2 expression and subcellular repartition are under the control of AVP. Some pieces of experimental evidence indicate that additional hormonal factors, including insulin, may also control AQP2 expression and thereby CD water permeability. We have previously shown that AVP induces endogenous AQP2 expression in cultured mouse mpkCCD(cl4) CD principal cells (23). In the present study, we investigated the effect of insulin on AQP2 expression in mpkCCD(cl4) cells. Addition of insulin to the basal medium of cells grown on filters slightly increased AQP2 mRNA and protein expression, whereas insulin potentiated the effect of AVP. The potentiation of AVP-induced AQP2 expression by insulin was abolished by actinomycin D, a transcriptional inhibitor. Analysis of AQP2 protein expression under conditions of AVP washout and/or in the presence of chloroquine, a lysosomal degradation inhibitor, revealed that insulin did not significantly alter AQP2 protein degradation. Inhibition of ERK, p38 kinase, and phosphatidylinositol 3'-kinase (PI 3-kinase) activities prevented the insulin-induced stimulation of AQP2 expression, whereas inhibition of PKC has no effect. Taken together, our results indicate that insulin increased AQP2 protein expression mostly through increased AQP2 mRNA levels in cultured mpkCCD(cl4) cells. This effect most likely relies on increased AQP2 gene transcription in response to MAPK and PI 3-kinase activation.
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PMID:Insulin potentiates AVP-induced AQP2 expression in cultured renal collecting duct principal cells. 1549 47

To examine the effect of the arginine-vasopressin fragment, [pGlu(4),Cyt(6)]AVP((4-9)) (AVP4-9), on group II metabotropic glutamate receptor (mGluR2/3) agonist and antagonist induced impairment of passive avoidance (PA) task performance, AVP4-9 or phorbol 12-myristate 13-acetate (PMA) was administered in the presence of mGluR2/3-related drugs that induced the impairment of the step-through-type PA task performance. The PA task performance was evaluated in terms of the latency (the time that elapsed prior to entry into the dark compartment) at 24 h after the electrical stimulation. The subcutaneous injection of AVP4-9 at 1 mug/kg had the greatest facilitative effect on the performance, and the facilitative effect of AVP4-9 was inhibited by NPC-15437, a specific protein kinase C (PKC) inhibitor. The injection of AVP4-9 ameliorated PA task performance impairment induced by DCG-IV, an mGluR2/3 agonist. Intracisternal injection of PMA, a PKC activator, also ameliorated the DCG-IV-induced impairment. High doses of AVP4-9 exacerbated the PA task performance impairment induced by LY341495 (an mGluR2/3 antagonist), and PMA injection (1 mug) also exacerbated the impairment induced by the antagonist. These results suggest that an increase in the activity of the PKC-signaling pathway may not always facilitate PA task performance; therefore, AVP4-9 can either enhance or inhibit memory performance in mice.
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PMID:Ameliorative and exacerbating effects of [pGlu(4),Cyt(6)]AVP((4-9)) on impairment of step-through passive avoidance task performance by group II metabotropic glutamate receptor-related drugs in mice. 1576 38

L-type Ca2+ channel activity was measured in L6 cells as nifedipine-sensitive barium (Ba2+; 5 mM) influx in a depolarizing salt solution containing 140 mM KCl. Addition of AVP (arginine-vasopressin) during Ba2+ uptake reduced the rate of Ba2+ influx by 60-100%; this was followed by a gradual restoration of the initial rate of Ba2+ uptake. Blockade of PKC (protein kinase C) by pretreatment with 10 muM bisindolylmaleimide did not affect the initial inhibition of Ba2+ influx, but completely abolished the recovery phase. The effect of AVP was half-maximal at 10 nM AVP and was blocked by the V1a receptor antagonist d-(CH2)(5)-Tyr(Me)-AVP. Activation of G(alphas) by isoprenaline or cholera toxin antagonized the actions of AVP on Ba2+ uptake. This protection persisted in the presence of the PKA (protein kinase A) inhibitor KT5720, and was not mimicked by agents that increase cAMP. Inhibition of Ba2+ influx was also elicited by ATP and ET (endothelin 1) with an order of effectiveness ET<ATP<AVP. Each of these agents has been reported to act through G(q)-coupled receptors. We conclude that activation of G(q)-coupled receptors produces a rapid inhibition of the cardiac L-type Ca2+ channel, which is subsequently overcome by activation of PKC.
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PMID:Regulation of the cardiac L-type calcium channel in L6 cells by arginine-vasopressin. 1691 57

As a hormone, vasopressin binds to three distinct receptors: V1a and V1b receptors, which induce phospholipase-Cbeta (PLCbeta) activation and Ca2+ mobilization; and V2 receptors, which are coupled to adenylyl cyclase. V1a and V1b receptors are also present in neurons. In particular, hypoglossal (XII) and facial (VII) motoneurons are excited following vasopressin-V1a receptor binding. The aim of the present study was double: (i) to determine whether V1b receptors contribute to the excitatory effect of vasopressin in XII and VII motoneurons; and (ii) to establish whether the action of vasopressin on motoneurons is mediated by Ca2+ signalling. Patch-clamp recordings were performed in brainstem slices of young rats. Vasopressin depolarized the membrane or generated an inward current. By contrast, [1-deamino-4-cyclohexylalanine] arginine vasopressin (d[Cha4]AVP), a V1b agonist, had no effect. The action of vasopressin was suppressed by Phaa-D-Tyr(Et)-Phe-Gln-Asn-Lys-Pro-Arg-NH2, a V1a antagonist, but not by SSR149415, a V1b antagonist. Thus, the vasopressin-induced excitation of brainstem motoneurons was exclusively mediated by V1a receptors. Light microscopic autoradiography failed to detect V1b binding sites in the facial nucleus. In motoneurons loaded with GTP-gamma-S, a non-hydrolysable analogue of GTP, the effect of vasopressin was suppressed, indicating that neuronal V1a receptors are G-protein-coupled. Intracellular Ca2+ chelation suppressed a Ca2+-activated potassium current, but did not affect the vasopressin-evoked current. H7 and GF109203, inhibitors of protein kinase C, were without effect on the vasopressin-induced excitation. U73122 and D609, PLCbeta inhibitors, were also without effect. Thus, excitation of brainstem motoneurons by V1a receptor activation is probably mediated by a second messenger distinct from that associated with peripheral V1a receptors.
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PMID:The vasopressin-induced excitation of hypoglossal and facial motoneurons in young rats is mediated by V1a but not V1b receptors, and is independent of intracellular calcium signalling. 1700 20

[Arg(8)]-vasopressin (AVP), at low concentrations (10-500 pM), stimulates oscillations in intracellular Ca(2+) concentration (Ca(2+) spikes) in A7r5 rat aortic smooth muscle cells. Our previous studies provided biochemical evidence that protein kinase C (PKC) activation and phosphorylation of voltage-sensitive K(+) (K(v)) channels are crucial steps in this process. In the present study, K(v) currents (I(Kv)) and membrane potential were measured using patch clamp techniques. Treatment of A7r5 cells with 100 pM AVP resulted in significant inhibition of I(Kv). This effect was associated with gradual membrane depolarization, increased membrane resistance, and action potential (AP) generation in the same cells. The AVP-sensitive I(Kv) was resistant to 4-aminopyridine, iberiotoxin, and glibenclamide but was fully inhibited by the selective KCNQ channel blockers linopirdine (10 microM) and XE-991 (10 microM) and enhanced by the KCNQ channel activator flupirtine (10 microM). BaCl(2) (100 microM) or linopirdine (5 microM) mimicked the effects of AVP on K(+) currents, AP generation, and Ca(2+) spiking. Expression of KCNQ5 was detected by RT-PCR in A7r5 cells and freshly isolated rat aortic smooth muscle. RNA interference directed toward KCNQ5 reduced KCNQ5 protein expression and resulted in a significant decrease in I(Kv) in A7r5 cells. I(Kv) was also inhibited in response to the PKC activator 4beta-phorbol 12-myristate 13-acetate (10 nM), and the inhibition of I(Kv) by AVP was prevented by the PKC inhibitor calphostin C (250 nM). These results suggest that the stimulation of Ca(2+) spiking by physiological concentrations of AVP involves PKC-dependent inhibition of KCNQ5 channels and increased AP firing in A7r5 cells.
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PMID:Vasopressin stimulates action potential firing by protein kinase C-dependent inhibition of KCNQ5 in A7r5 rat aortic smooth muscle cells. 1707 36

Current scientific literature generally attributes the vasoconstrictor effects of [Arg(8)]vasopressin (AVP) to the activation of phospholipase C (PLC) and consequent release of Ca(2+) from the sarcoplasmic reticulum. However, half-maximal activation of PLC requires nanomolar concentrations of AVP, whereas vasoconstriction occurs when circulating concentrations of AVP are orders of magnitude lower. Using cultured vascular smooth muscle cells, we previously identified a novel Ca(2+) signaling pathway activated by 10-100 pM AVP. This pathway is distinguished from the PLC pathway by its dependence on protein kinase C (PKC) and L-type voltage-sensitive Ca(2+) channels (VSCC). In the present study, we used isolated, pressurized rat mesenteric arteries to examine the contributions of these different Ca(2+) signaling mechanisms to AVP-induced vasoconstriction. AVP (10(-14)-10(-6) M) induced a concentration-dependent constriction of arteries that was reversible with a V(1a) vasopressin receptor antagonist. Half-maximal vasoconstriction at 30 pM AVP was prevented by blockade of VSCC with verapamil (10 microM) or by PKC inhibition with calphostin-C (250 nM) or Ro-31-8220 (1 microM). In contrast, acute vasoconstriction induced by 10 nM AVP (maximal) was insensitive to blockade of VSCC or PKC inhibition. However, after 30 min, the remaining vasoconstriction induced by 10 nM AVP was partially dependent on PKC activation and almost fully dependent on VSCC. These results suggest that different Ca(2+) signaling mechanisms contribute to AVP-induced vasoconstriction over different ranges of AVP concentration. Vasoconstrictor actions of AVP, at concentrations of AVP found within the systemic circulation, utilize a Ca(2+) signaling pathway that is dependent on PKC activation and can be inhibited by Ca(2+) channel blockers.
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PMID:Vasopressin-induced vasoconstriction: two concentration-dependent signaling pathways. 1720 77

Vasopressin V(1a) and V(2) receptors (V(1a)R and V(2)R, respectively) distribute in the collecting duct of the kidney. Although the function of V(2)R mediating the antidiuretic effect of AVP has been investigated in detail, the role of V(1a)R in the collecting ducts has not been elucidated. In the present study, we have investigated the role of the V(1a)R pathway in V(2)R promoter activity. We cloned the 5'-flanking region of rat V(2)R (rV(2)R) and investigated rV(2)R promoter activity in the LLC-PK(1) cell line transfected to express rat V(1a)R (rV(1a)R) dominantly (LLC-PK(1)/rV(1a)R). AVP induced a transient increase, followed by a sustained decrease, of rV(2)R promoter activity in these cells. This AVP-induced decrease of rV(2)R promoter activity was inhibited by V(1a)R, but not V(2)R, antagonist. PMA mimicked this decrease of rV(2)R promoter activity. On the contrary, 8-(4-chlorophenylthio)-cAMP increased rV(2)R promoter activity. These PMA- and 8-(4-chlorophenylthio)-cAMP-induced effects were not observed on the deletion segment of the 5'-flanking region lacking CAAT and SP1 sites. In conclusion, 1) expression of the V(2)R is downregulated via the V(1a)R pathway in LLC-PK(1)/rV(1a)R cells, and 2) expression of the V(2)R is downregulated by the PMA-induced PKC pathway and upregulated by the cAMP-PKA pathway. These opposite effects of PKC and PKA appear to be regulated by the same promoter region of CAAT and SP1.
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PMID:Downregulation of vasopressin V2 receptor promoter activity via V1a receptor pathway. 1721 62

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