Interaction between supraoptic nucleus and septal area in the control of water, sodium intake and arterial blood pressure induced by injection of angiotensin II

We investigated the effects of injection into the supraoptic nucleus (SON) of losartanand PD 123319 (nonpeptide AT(1) and AT(2)- angiotensin II [ANG II] receptor antagonists, respectively); d(CH2)(5)-Tyr(Me)-AVP (AVPA; an arginine-vasopressin [AVP] V-1 receptor antagonist), FK 409 (a nitric oxide [NO] donor), and N-W-mtro-(L)-arginine methyl ester ((L)-NAME; an NO synthase inhibitor) oil water intake, sodium chloride 3% (NaCl) intake and arterial blood pressure induced by injection of ANG 11 into the lateral septal area (LSA). Mate Holtzman rats (250-300 g) were implanted with cannulae into SON and LSA unilaterally. The drugs were injected in 0.5 mul over 30-60 s. Controls were injected with a similar volume of 0.15 M NaCl. ANG II was injected at a dose of 10 pmol. ANG II antagonists and AVPA were injected at doses of 80 nmol. FK 409 and (L)-NAME were injected at doses of 20 and 40 mug, respectively. Water and NaCl intake was measured over a 2-h period. Prior administration of losartan into the SON decreased water and NaCl intake induced by injection of ANG II. While there was a decrease in water intake, ANG II-induced NaCl intake was significantly increased following injection of AVPA. FK 409 injection decreased water intake and sodium intake induced by ANG II. L-NAME alone increased water and sodium intake and induced a pressor effect. (L)-NAME-potentiated water and sodium intake induced by ANG II. PD 123319 produced no changes in water or sodium intake induced by ANG II. The prior administration of losartan or AVPA decreased mean arterial pressure (MAP) induced by ANG II. PD 123319 decreased the pressor effect of ANG II to a lesser degree than losartan. FK 409 decreased the pressor effect of ANG II while (L)-NAME potentiated it. These results suggest that both ANG II AT, and AVP V, receptors and NO within the SON may be involved in water intake, NaCl intake and the pressor response were induced by activation of ANG II receptors within the LSA. These results do not support the involvement of LSA AT(2) receptors in the mediation of water and NaCl intake responses induced by ANG II, but influence the pressor response. (C) 2004 Elsevier B.V. All rights reserved.

Episodes of water deprivation enhance daily hypertonic NaCl intake in rats

Water and 1.8% NaCl intake was recorded daily in adult male rats (N = 6) submitted to four water deprivations plus four sodium appetite tests, each at the end of each 7-day interval, or in controls (non-deprived, N = 6). Water deprivation was achieved by removing water and 1.8% NaCl for 24 h. Water was then offered for 2 h. At the end of this period, 1.8% NaCl was also offered in addition to water (sodium appetite test). Average daily 1.8% NaCl intake was enhanced from 5.2 ± 1.0 to 15.7 ± 2.5 ml from the first to the fifth week in the experimental group and was unchanged in the control group. Daily water intake was not altered in either group. Thus, repeated episodes of water deprivation enhance daily NaCl intake.

On a possible dual role for the lateral septal area 5-HT1A receptor system in the regulation of water intake and urinary excretion

The 5-hydroxytryptamine (5-HT)(1A) receptor system plays a prominent role in a variety of physiological functions and behavior and regulation of this responsiveness of the receptor system has been implicated in the central regulation of water intake and urinary excretion. The lateral septal area (LSA) exhibits a high density of 5-HT1A receptors, as well as a subpopulation of oxytocin (OT) receptors. Here we report the effects of pMPPF (a selective 5-HT1A antagonist), d(CH2)(5)[Tyr(Me)(2)Thr(4), Orn(5), Tyr(NH2)(9)]-vasotocin (an OT antagonist), and that 5-HT1A receptor system is regulated as a consequence of activation of the Na+ channel by veratridine. Cannulae were implanted into the LSA of rats to enable the introduction of the drugs. Injections of 8-OH-DPAT (a 5-HT1A agonist) blocked water intake and increased urinary excretion, while pMPPF or the OT antagonist injected bilaterally before 8-OH-DPAT blocked its inhibitory effect on water intake and its diuretic effect. In contrast, increases in extracellular sodium levels induced by the sodium channel modulator, veratridine, enhanced 5-HT1A responsiveness for water intake and reduced the diuretic effects induced by 8-OH-DPAT. These trials demonstrated that the responsiveness of the 5-HT1A receptor system in the LSA can be enhanced or depressed as a consequence of an induced rise in extracellular sodium. (C) 2010 Elsevier B.V. All rights reserved.

Adrenergic mechanisms of the Kölliker-Fuse/A7 area on the control of water and sodium intake

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Effect of water storage on the shear strength and fatigue limit of the reline resin bond to denture base resins

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Effect of water storage and heat treatment on the cytotoxicity of soft liners

Objective: To evaluate the effect of water storage time on the cytotoxicity of soft liners.Methods: Sample discs of soft liners Dentusoft, Dentuflex, Trusoft, Ufi-Gel-P and denture base acrylic resin Lucitone-550 were prepared and divided into four groups: GN: No treatment, G24: Stored in water at 37 degrees C for 24 h; G48: Stored in water at 37 degrees C for 48 h, GHW: Immersed in water at 55 degrees C for 10 min. To analyse the cytotoxic effect, three samples of each group were placed in tubes with Dubelcco's Modified Eagle Mediums and incubated at 37 degrees C for 24 h. During this period, the toxic substances were leached to the culture medium. The cytotoxicity was analysed quantitatively by the incorporation of radioactivity H-3-thymidine checking the number of viable cells (synthesis of DNA). The data were statistically analysed using two-way ANOVA and Tukey's honestly significant difference tests (alpha = 0.05).Results: Treatments did not reduce the cytotoxicity effect of the soft liners (p > 0.05). It was found that Ufi-Gel-P had a non-cytotoxic effect, Trusoft had a slightly cytotoxic effect, Dentuflex had a moderated cytotoxic effect, Dentusoft alternated between slightly and non-cytotoxic effect, and Lucitone-550 had non-cytotoxic effect when stored in water for 48 h.Conclusion: The effect of water storage and the heat treatment did not reduce the cytotoxicity of the soft liners.

Leachability of degradation products from hard chairside reline resins in artificial saliva: effect of water-bath post-polymerization treatment

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Effect of water-bath post-polymerization on the mechanical properties, degree of conversion, and leaching of residual compounds of hard chairside reline resins

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Expression of differential genes involved in the maintenance of water balance in human skin by Piptadenia colubrina extract

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Drought tolerance is associated with rooting depth and stomatal control of water use in clones of Coffea canephora

center dot Background and Aims Drought is a major environmental constraint affecting growth and production of Coffea canephora. Selection of C. canephora clones has been largely empirical as little is known about how clones respond physiologically to drought. Using clones previously shown to differ in drought tolerance, this study aimed to identify the extent of variation of water use and the mechanisms responsible, particularly those associated morphological traits.center dot Methods Clones (14 and 120, drought-tolerant; 46 and 109A, drought-sensitive, based on their abilities to yield under drought) were grown in 120-L pots until they were 12-months old, when an irrigation and a drought treatment were applied; plants were droughted until the pressure potential (Psi(x)) before dawn (pre-dawn) reached -3.0 MPa. Throughout the drought period, Psi(x) and stomatal conductance (g(s)) were measured. At the end of the experiment, carbon isotope ratio and parameters from pressure-volume curves were estimated. Morphological traits were also assessed.center dot Key Results and Conclusions With irrigation, plant hydraulic conductance (K-L), midday Psi(x) and total biomass were all greater in clones 109A and 120 than in the other clones. Root mass to leaf area ratio was larger in clone 109A than in the others, whereas rooting depth was greater in drought-tolerant than in drought-sensitive clones. Predawn Psi(x) of -3.0 MPa was reached fastest by 109A, followed progressively by clones 46, 120 and 14. Decreases in g(s) with declining Psi(x), or increasing evaporative demand, were similar for clones 14, 46, and 120, but lower in 109A. Carbon isotope ratio increased under drought; however, it was lower in 109A than in other clones. For all clones, Psi(x), g(s) and KL recovered rapidly following re-watering. Differences in root depth, KL and stomatal control of water use, but not osmotic or elastic adjustments, largely explained the differences in relative tolerance to drought stress of clones 14 and 120 compared with clones 46 and 109A.

Changes in abiotic characteristics of water in the Paranapanema River and three lateral lagoons at mouth zone of the Jurumirim Reservoir during the flood period, São Paulo, Brazil

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Photosynthetic limitations caused by different rates of water-deficit induction in Glycine max and Vigna unguiculata

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Studies on the electrochemical disinfection of water containing Escherichia coli using a Dimensionally Stable Anode

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A thin layer electrochemical cell for disinfection of water contaminated with Staphylococcus aureus

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Performance of the constructed wetland system for the treatment of water from the corumbataí river

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