Synthetic pigments for Japanese quail fed diets with sorghum / Pigmentantes sintéticos para codornas japonesas alimentadas com rações à base de sorgo

Corn is the major energy ingredient in diets, and many ingredients have been tested aiming to replace it. In this regard, sorghum stands out for its chemical profile similar to that of corn. However, because it is low in carotenoids, its inclusion in diets reduces the egg yolk color pigmentation, which can be corrected by the addition of synthetic pigments. This study aimed to evaluate the performance and egg quality of Japanese quail (Coturnix japonica) supplemented with red (canthaxanthin) and yellow (apo-ester 10%) synthetic pigments. A total of 150 quail at 70 days of age were distributed according to the experimental diet [R1: corn-based control diet (DC); R2: sorghum-based diet (DS); R3: DS + yellow; R4: DS + yellow + red; and R5: DS + red] with six replications and five birds per experimental unit, for 28 days. Performance, egg quality, yolk color, and feed cost characteristics were evaluated. Regression equations were estimated for the effects of color as a function of periods, and treatment means were compared by Tukey's test at 0.05 probability. There was no significant effect (P>0.05) of additives on the quail productive traits. However, addition of synthetic pigments significantly improved the chromatic profile of the yolks (P<0.05). Inclusion of synthetic pigments improves yolk color, but should be evaluated according to market demands.(AU)

O milho é o principal ingrediente energético nas rações. A fim de substituí-lo, vários ingredientes foram testados. Nesse sentido, destaca-se o sorgo, pois apresenta perfil bromatológico semelhante ao do milho. No entanto, por ser deficiente em carotenoides, sua inclusão na ração reduz a pigmentação da gema do ovo, o que pode ser corrigido por meio da adição de pigmentos sintéticos. Objetivou-se, com este estudo, avaliar o desempenho zootécnico e a qualidade dos ovos de codornas japonesas (Coturnix japonica) suplementadas com os pigmentantes sintéticos vermelho (cantaxantina) e amarelo (apoéster 10%). Foram utilizadas 150 codornas japonesas com 70 dias de idade, distribuídas de acordo com a ração experimental (R1: ração referência à base de milho; R2: ração à base de sorgo (RS); R3: RS + amarelo; R4: RS + amarelo + vermelho; R5: RS + vermelho), com seis repetições e cinco aves por unidade experimental, durante 28 dias. Foram avaliadas as características de desempenho, qualidade dos ovos, cor da gema e custo das rações. Equações de regressão dos efeitos da cor em função dos períodos foram estimadas, e as médias de tratamento foram comparadas pelo teste de Tukey com 0,05 de probabilidade. Não houve efeito significativo (P>0,05) dos aditivos sobre as características produtivas das codornas. Entretanto, a adição de pigmentantes sintéticos melhorou significativamente o perfil cromático das gemas dos ovos de codornas (P<0,05). A inclusão de pigmentantes sintéticos melhora a cor das gemas, porém deve ser avaliada de acordo com as exigências de mercado.(AU)

Processamento do milho para vacas leiteiras em pastejo / Processing of corn for grazing dairy cows

Doze vacas lactantes Holandês-Gir (1/2), em sistema de pasto rotativo de Panicum maximum cv. Mombaça, foram suplementadas com concentrados contendo milho seco finamente moído (MM), milho expandido (ME), milho floculado a vapor (MF) ou milho moído reidratado e ensilado (MU). O delineamento experimental adotado foi o de quadrado latino 4 x 4, com três repetições. O consumo de pasto foi maior quando as vacas foram suplementadas com MF, o que se refletiu em maior consumo de MS, PB, FDN para o mesmo tratamento. A digestibilidade aparente da MS foi maior para as dietas de MF e MM. A digestibilidade aparente da FDN foi menor para MU. A produção e composição do leite das vacas não diferiram entre os tratamentos, entretanto a eficiência alimentar foi menor para MF...

Twelve lactating Holstein-Gyr (1/2) cows in a rotational grazing system with Panicum maximum cv. Mombasa were supplemented with different concentrates containing finely ground dried corn (MM), expanded corn (ME), steam flaked corn (MF) or silage of re-hydrated ground corn (MU). The experiment was arranged in a 4 x 4 Latin square design with three replications. Pasture intake was higher when cows were supplemented with MF, which resulted in higher DM, CP, and NDF. The apparent digestibility of DM was higher for MF and MM diets. The NDF apparent digestibility was lower for MU. Milk yield and composition did not differ between treatments; however, feed efficiency was lower for MF...

Efeito dos ácidos graxos essenciais sobre lipidemia e vascularização da membrana vitelina de codornas japonesas / Effect of essential fatty acids on lipidemia and vitelline membrane vascularization in Japanese quails

Verificou-se o efeito de diferentes fontes de ácidos graxos essenciais ômega-3 e ômega-6 sobre o perfil lipídico de codornas japonesas e sobre o crescimento vascular na membrana vitelina dos embriões de aves suplementadas com óleo de peixe, 2% e 4%, e óleo de soja, 2% e 4%, em relação à dieta-controle, sem suplementação lipídica. Foi usado o método enzimático com reação colorimétrica para estimar o perfil lipídico sérico de colesterol total, triglicerídeos e HDL das aves. A vascularização na membrana vitelina foi quantificada por meio da dimensão fractal, utilizando-se o método de box-counting. A concentração de colesterol dos grupos controle e tratados não diferiu entre si. Para o HDL, o grupo que recebeu maior proporção de óleo de peixe, 4%, diferiu dos outros grupos. Os níveis de triglicerídeos das codornas suplementadas com óleo de peixe foram superiores aos dos demais grupos. A dimensão fractal da vascularização da membrana vitelina dos embriões de codornas dos grupos que receberam 4% de óleo de peixe e 4% de óleo de soja foi significativamente menor que a dos demais grupos, indicando efeitos antiangiogênicos no processo de formação vascular.

The effect of different sources of omega-3 and omega-6 essential fatty acids on serum lipid profile in Japanese quails and on vascular growth in the embryos vitelline membrane was verified. The birds were supplemented with fish oil, 2% and 4%, and soybean oil, 2% and 4%, and one control diet, without lipid supply. The enzymatic method with colorimetric reaction was used to estimate the profile of serum total cholesterol, triglycerides and HDL of the birds. Vitelline membrane vascularization was measured using the box-counting fractal dimension. The cholesterol concentration of the treated and control groups showed no difference. For HDL, the group treated with a higher proportion of fish oil, 4%, differed from other groups. The triglycerides levels of quails supplemented with fish oil were higher than the other groups. The fractal dimension of quail embryos vitelline membrane from the groups treated with 4% fish oil and 4% soybean oil was lower than the other groups, indicating antiangiogenic effects on the vascular formation process.

Efeito do nível nutricional antes e após a ovulação sobre a taxa de gestação e a prolificidade em ovelhas Santa Inês / Effect of the nutritional level before and after ovulation on pregnancy rate and prolificacy in Santa Ines ewes

Quarenta e três ovelhas foram distribuídas em quatro tratamentos em um delineamento de blocos casualizados. Os tratamentos consistiram no fornecimento de dietas de flushing, formuladas com farelo de soja (FFS) ou com glúten de milho e farelo de algodão (FGM+FA) por 28 dias antes da ovulação, seguido pelo fornecimento de dietas de flushing ou de uma dieta de mantença (DM) durante 28 dias após a ovulação: T1 - FFS antes e após a ovulação (n=12); T2 - FFS antes da ovulação e DM após (n=11); T3 - FGM+FA antes e após a ovulação (n=10); T4 - FGM+FA antes da ovulação e DM após (n=10). O ganho de peso e o peso final não diferiram (P>0,05) entre os animais dos tratamentos. O ECC final foi maior (P<0,05) nas ovelhas do tratamento T3 do que nas do tratamento T2. A concentração de N-ureico foi maior (P<0,05) nas ovelhas dos tratamentos T1 e T3 do que naquelas dos tratamentos T2 e T4. A taxa de gestação e a prolificidade não diferiram (P>0,05) entre os animais. As dietas de flushing antes da ovulação, seguidas pelo fornecimento destas mesmas dietas ou de uma dieta de mantença após a ovulação, não alteraram a taxa de gestação e a prolificidade.

Forty-tree ewes were assigned to four treatments in a randomized block design. The treatments consisted of two flushing diets, composed of soybean meal (SMF) or corn gluten and cottonseed meal (CG+CMF) furnished for 28 days before ovulation, and feeding with flushing diets or a maintenance diet (MD) for 28 days after ovulation: T1 - (SMF) before and after ovulation (n=12); T2 - SMF before ovulation and a MD after (n=11); T3 - CG+CMF before and after ovulation (n=10); T4 - CG+CMF before ovulation and MD after (n=10). The gain in BW and the final BW did not differ (P>0,05) between treatments. The final BC was higher (P>0,05) in ewes in T3 treatment than in those in treatment T2. The urea N concentration was higher (P<0,05) in ewes in treatments T1 and T3 than those in treatments T2 and T4. The pregnancy rate and prolificacy did not differ (P>0,05) between treatments. The flushing diets before ovulation and feeding with this same diet or a maintenance diet after ovulation did not alter the pregnancy rate and prolificacy.

Determinação da energia metabolizável de alimentos para codornas japonesas em postura / Metabolizable energy of different feedstuffs tested in female Japanese quails

Foram determinados os valores de energia metabolizável aparente (EMA), de energia metabolizável aparente corrigida por retenção de nitrogênio (EMAn) e do coeficiente de metabolização aparente da energia bruta (CMAEB por cento) do milho, sorgo, farelo de soja, farelo de glúten de milho e óleo de soja refinado. Foram utilizadas 240 codornas japonesas (Coturnix japonica), fêmeas com idade inicial de 60 dias, em delineamento experimental inteiramente ao caso, com seis tratamentos, cinco repetições e oito codornas por unidade experimental. Os tratamentos consistiram de cinco rações experimentais e uma ração referência. Cada ração experimental foi constituída, na base da matéria natural, por 70 por cento da ração referência e 30 por cento do ingrediente a ser testado, com exceção da ração para determinação da EMAn do óleo de soja, com 10 por cento de inclusão e 90 por cento da ração referência. O experimento foi realizado em gaiolas distribuídas em baterias metálicas. Os valores de EMA, EMAn (em kcal/kg de matéria natural) e do CMAEB ( por cento) do milho moído, sorgo, farelo de soja, farelo de glúten de milho e óleo de soja refinado foram, respectivamente: 3.572 e 3.612kcal/kg e 92,6 por cento; 3.108 e 3.149kcal/kg e 80,9 por cento; 2.633 e 2.676kcal/kg e 65,3 por cento; 4.043 e 4.096kcal/kg e 75,0 por cento; 9.335 e 9.379kcal/kg e 98,8 por cento. Os valores de EMA descritos para outras espécies de aves são discrepantes dos obtidos no presente estudo, não sendo recomendado seu uso em formulação de rações para codornas japonesas em postura.

The values of the apparent metabolizable energy (AME), the apparent metabolizable energy corrected for nitrogen retention (AMEn), and the apparent metabolization coefficient of crude energy (AMCCE) were determined in corn, sorghum, soybean meal, corn gluten meal, and refined soybean oil. Two-hundred and forty six-day-old female Japanese quails (Coturnix japonica) were used in a completely randomized design, with five replicates and eight quails per experimental unit. The treatments consisted of six experimental diets and one reference diet. Each experimental diet was constituted, as fed basis, for 70 percent of the reference ration and 30 percent of food that would be tested, except the ration that contained refined soybean oil that was tested, as fed basis, with 10 percent of addition and 90 percent of the reference ration. The biological assay was carried out in wired floor cages distributed in iron batteries. The respective values of AME, AMEn (kcal/kg of natural matter basis), and AMCCE ( percent) of ground corn, sorghum, soybean meal, corn gluten meal, and refined soybean oil were respectively: 3,572, 3,612kcal/kg, and 92.6 percent; 3,108, 3,149kcal/kg, and 80.9 percent; 2,633, 2,676kcal/kg, and 65.3 percent; 4,043, 4,096kcal/kg, and 75.0 percent; and 9,335, 9,379kcal/kg, and 98.8 percent. The values of AME described for other birds species were different from those obtained in this study and are not recommended to be used in ration composition for Japanese quails.

[Ex vivo and in vitro effects of trandolapril on the efflux of 22Na from the caudal artery of the SHR rat. Inhibition of vascular angiotensin II production]. / Effets ex vivo et in vitro du trandolapril sur les efflux de 22Na de l'artère caudale du rat SHR. Inhibition d'une production vasculaire d'angiotensine II.

The inhibition of converting enzyme (CE) activity in target tissues other than blood and lung vascular endothelium may be important for the antihypertensive action of CE inhibitors (ICE) (Unger et al 1983). In order to determine if ICE may have an effect on the transmembrane Na movements implicated in the regulation of vascular tone, we have studied the effects of trandolapril and enalapril on 22Na effluxes from the tail artery of 20 weeks old SHR. In vivo, the chronic oral treatment (14 days) with trandolapril (1.3 mg/kg/day) decreased the ouabain-sensitive 22Na efflux (controls: 0.050 +/- 0.004 min-1 (n = 8); trandolapril (1 mg/kg): 0.030 +/- 0.03 min-1 (n = 10) p less than 0.01), and the ouabain-insensitive 22Na efflux (controls: 0.088 +/- 0.0030 min-1; trandolapril (1 mg/kg): 0.080 +/- 0.003 min-1 (n = 10) p less than 0.05). Enalapril had no effect at the dose of 10 mg/kg/day (14 days). In vitro, trandolapril diacid (RU 44403) decreased the ouabain-sensitive 22Na efflux (controls: 0.045 +/- 0.002 min-1 (n = 6); RU 44403 (10(-9) M): 0.031 +/- 0.002 min-1 (n = 6) p less than 0.01), and the ouabain-insensitive efflux (controls: 0.096 +/- 0.004 min-1 (n = 6); RU 44403 (10(-9) M): 0.084 +/- 0.006 min-1 (n = 6) p less than 0.05). The effects were dose-dependent. Enalapril diacid (MK 422) also dose-dependently decreased 22Na effluxes but it was approximately 10 fold less active.(ABSTRACT TRUNCATED AT 250 WORDS)

Interaction between aldosterone and vasopressin on vascular smooth muscle permeability to sodium.

The s.c. injection of aldosterone (10 micrograms/kg) induces a release of vasopressin. The peak of plasma vasopressin level occurs at the same time as the late in vivo effect of aldosterone on passive 22Na efflux from arterial smooth muscle. These results indicate that vasopressin mediates the delayed in vivo effects of aldosterone on ouabain-insensitive 22Na efflux, since on the other hand, it has been possible to show that the action of the peptide is accelerated by a previous exposure to the mineralocorticoid. Indeed, after a 120-min pretreatment with 10(-8) M aldosterone, vasopressin induces an effect on 22Na efflux in 30 min, as opposed to the 120 min needed in the absence of the steroid.

Prevention by calcitonin of the pathological modifications of the rabbit arterial wall induced by immunization with elastin peptides: effect on vascular smooth muscle permeability to ions.

Immunization of rabbits with elastin peptides prepared from purified bovine ligamentum nuchae elastin produces calcified arteriosclerotic lesions and fragmentation of elastic lamellae. Simultaneous administration of porcine calcitonin largely prevents the development of lesions. Experiments were carried out to clarify the mechanisms involved in the development of lesions as well as those involved in the preventive effect of calcitonin. Control experiments were carried out using bovine serum albumin (BSA) as antigen. Circulating antibodies and soluble immune complexes increased steadily in the sera of animals immunized with elastin peptides or BSA. The cellular immune reaction was weak as assessed by [3H]thymidine incorporation into lymphocytes in the presence of antigen or phytohemagglutinin. Arterial lesions appeared only in the animals immunized with elastin peptides, not in those immunized with BSA. Ion flux measurements were also carried out on strips of aorta obtained from immunized and control animals. Immunization with elastin peptides significantly increased the ouabain-insensitive 22Na+ efflux, the 86Rb efflux (indicator of K+ efflux), and the 45Ca2+ influx. Simultaneous calcitonin administration prevented the increase in Ca2+ influx but did enhance passive permeability to Na+ and K+ as well as the sodium pump. When calcitonin was administered without immunization, it decreased arterial smooth muscle permeability to Na+ and K+ and also decreased the basal Ca2+ influx. It is concluded that the pathological modifications of the arterial wall triggered by immunization with elastin peptides is at least partly mediated by the effect of antielastin antibodies and immune complexes on the ion permeability of arterial smooth muscle. Prevention of the increased Ca2+ influx by calcitonin is probably a key effect in the prevention of the development of lesions. The fact that calcitonin alone can modify the ion permeability of arterial smooth muscle suggests that this hormone may play a role in the regulation of vascular homeostasis.

[Involvement of vasopressin in the effects of aldosterone on the arterial wall]. / Implication de la vasopressine dans les effets de l'aldostérone sur la paroi artérielle.

We have previously shown that an humoral factor is involved in the delayed effect of aldosterone on the passive transmembrane movements of Na+ from arterial smooth muscle (Moura and Worcel, 1984). In absence of vasopressin, the effects of aldosterone on the same Na transports suggest that vasopressin may be this humoral factor (Moura, Angeli and Worcel, 1986) (Angeli, Moura and Worcel, 1986). We show here that the s.c. injection of aldosterone (10 micrograms/kg) to adrenalectomized Sprague Dawley rats induces a release of vasopressin. This peptide exerts a direct action on ouabain-sensitive and insensitive components of 22Na efflux from the rat tail artery, and potentiates the late effect of aldosterone on passive Na+ efflux. There is no additive effect of the two hormones on Na+ pump activity. In conclusion vasopressin is the humoral factor involved in the late effect of aldosterone on passive transmembrane movement of Na from vascular smooth muscle.

Arterial effects of aldosterone and antimineralocorticoid compounds mechanism of action.

The aim of our work was to study the mechanism of action of aldosterone and antialdosterone compounds on Na+ and K+ fluxes in vascular smooth muscle. In the long term, regulation of salt metabolism depends on aldosterone effects on Na+, K+, H+ and H2O transport by the renal tubules. Furthermore, it has been shown that aldosterone modifies several epithelial transports, inducing a positive sodium balance. The chronic in vivo administration of aldosterone modifies transmembrane ionic fluxes in vascular smooth muscle. Garwitz and Jones suggested that aldosterone may enhance net Na+ transport through the stimulation of the sodium pump. The results obtained in our laboratory indicate that aldosterone has a direct stimulatory action on ouabain-dependent and on ouabain-independent Na efflux. Furthermore, the mineralocorticoid enhances passive K permeability, as well as the Na pump dependent K influx. Both effects are blocked by antimineralocorticoid compounds. Recent experiments have shown that vasopressin potentiates some of the in vivo effects of aldosterone.

[Effects of aldosterone and vasopressin on transmembrane efflux of sodium from the arterial wall]. / Effets de l'aldostérone et de la vasopressine sur les transferts transmembranaires de sodium de la paroi artérielle.

We have previously shown that, injected s.c. to adrenalectomized Sprague-Dawley rats (SD.ADx), aldosterone has a mineralocorticoid specific effect on transmembrane movements of 22Na from arterial smooth muscle. These effects appear to be partly due to the action of an humoral factor. Indeed, in vitro, the late increase in passive 22Na efflux is not observed (Moura and Worcel, 1984). In rats perfused with a specific antagonists of the pressor effect of vasopressin (Vp), the in vivo administration of aldosterone induced a kinetic action similar to that observed after in vitro exposure to the mineralocorticoid. These results suggested that Vp may be the humoral factor (Moura, Angeli and Worcel, 1985). In adrenalectomized homozygous Brattleboro rats (DI.ADx), aldosterone (10(-8)M) increases ouabain independent 22Na efflux (DI.AX: 0.073 +/- 0.002 min-1(n = 15); DI.ADx + Aldo: 0.096 +/- 0.002 min-1(n = 12)p less than 0.01) and ouabain-dependent 22Na efflux (DI.ADx: 0.031 +/- 0.001 min-1; DI.ADx + Aldo: 0.037 +/- 0.002 min-1 p less than 0.01). Vp also increases ouabain sensitive and insensitive 22Na effluxes and potentiates the effects of aldosterone on passive Na+ transferts (DI.ADx + Aldo + Vp: 0.015 +/- 0.003 min-1 (n = 16) p less than 0.01). In conclusion, these results suggest that Vp may be involved in the effects of aldosterone on 22Na effluxes. Furthermore Vp potentiates the effects of aldosterone on passive 22Na effluxes. But it is not yet possible to ascertain if Vp action is additive or permissive.

Arterial smooth muscle effects of aldosterone and vasopressin: action on ionic fluxes.

We have shown previously that aldosterone injected s.c. to adrenalectomized rats has a mineralocorticoid specific action on the transmembrane movements of sodium and potassium from the rat tail artery. These effects appeared to be partly due to an unknown humoral factor. Indeed, the late in vivo effects of aldosterone on 22Na and 86Rb effluxes are suppressed or reduced after in vitro exposure to the hormone. In rats perfused with a specific antagonist of the pressor effect of vasopressin, the in vitro administration of aldosterone induced a kinetic action similar to that observed after in vitro exposure to the mineralocorticoid. Vasopressin exerts a direct action on 22Na and 86Rb effluxes. These effects were correlated in the time with the late in vivo effects of aldosterone. Moreover, vasopressin appears to potentiate the in vitro effects of aldosterone on 22Na and 86Rb effluxes. It is not yet possible to ascertain if this effect is additive or permissive.

Effects of antiglucocorticoids on glucocorticoid hypertension in the rat.

The early phase of hypertension induced in rats by a glucocorticoid agonist RU 26988 was studied. Systolic blood pressure increased by 35 mm Hg. Water and sodium urinary excretion increased transiently, and plasma volume decreased. Total and ouabain-sensitive sodium efflux, as well as rubidium efflux, were enhanced by glucocorticoid administration. Low salt intake did not prevent hypertension. Pretreatment with RU 38486, a steroid with antiglucocorticoid properties, largely prevented the rise in blood pressure (+10 mm Hg) and suppressed transient natriuresis and the decrease in plasma volume. Changes in total and ouabain-sensitive sodium efflux were completely prevented, whereas changes in rubidium efflux were only partly reversed. Similarly, administration of progesterone, a steroid with antiglucocorticoid effects, prevented glucocorticoid hypertension (+11 mm Hg) and vascular ionic changes. In contrast administration of RU 28318, an antimineralocorticoid agent, was without effect on glucocorticoid hypertension (+38 mm Hg). Progesterone or RU 38486 administered after glucocorticoid also decreased blood pressure. Present data indicate that glucocorticoid hypertension may be prevented or reversed in its early phase by steroid drugs with antiglucocorticoid properties. These drugs also appeared to prevent the sodium and rubidium flux abnormalities induced by glucocorticoid. We suggest that activation of the vascular glucocorticoid receptors may be involved in the pathophysiology of glucocorticoid hypertension.

[Effect of an antiglucocorticoid steroid on the arterial hypertension induced by glucocorticoids in the rat]. / Effet d'un stéroïde antiglucocorticoïde sur l'hypertension artérielle induite par les glucocorticoïdes chez le rat.

Hypertension was induced in male rats by administration of a glucocorticoid agonist, RU 26988. Systolic blood pressure (SBP) increased by 35 mmHg. Administration of an antimineralocorticoid derivative, RU 28318, did not modify hypertension. In contrast administration of a steroid derivative with antiglucocorticoid properties, RU 38486, prevented glucocorticoid-induced hypertension in a large part. SBP augmented only by 10 mmHg. The glucocorticoid increased total and active, ouabain-sensitive, 22Na efflux, as measured from caudal arteries, whereas concomitant administration of the antiglucocorticoid derivative prevented these changes. It is suggested that glucocorticoid-induced hypertension may be related to vascular Na pump activation and to the subsequent ionic changes. These changes, as well as hypertension, are antagonized by steroid derivatives with antiglucocorticoid properties.

Direct action of aldosterone on transmembrane 22Na efflux from arterial smooth muscle. Rapid and delayed effects.

Acute subcutaneous (s.c.) administration of aldosterone increases ex vivo 22Na efflux from rat tail artery smooth muscle, which appears to be due to a specific action on mineralocorticoid receptors. Indeed, this effect is blocked by the antimineralocorticoid compounds RU 28318 [17 beta-hydroxy-3-oxo,7 alpha-propyl(17 alpha)-pregn 4-ene, 21 potassium carboxylate] and spironolactone. The specific glucocorticoid receptor agonist RU 26988 [11 beta,17 beta-dihydroxy-17-(1-propynyl) androesta-1,4,6 trien-3-one] does not modify 22Na efflux. We show here that aldosterone has, at physiological concentrations, a mineralocorticoid specific stimulating effect on passive and sodium pump dependent transmembrane movements of sodium from the rat tail artery smooth muscle. Aldosterone exerts two types of action on sodium transport: 1) a delayed stimulation of ouabain-dependent 22Na efflux and ouabain-independent 22Na efflux, which are completely blocked by actinomycin D; and 2) a very rapid increase of passive 22Na efflux, which is insensitive to actinomycin D and therefore does not seem to depend on transcription of genomic information.

Mode of action of cyclothiazide and triamterene. Ex vivo effect on 22Na and 86Rb efflux from arterial smooth muscle.

Acute oral cyclothiazide treatment of conscious rats increased ex vivo 86Rb efflux from tail artery smooth muscle. This effect was blocked by oral triamterene. Identical results were obtained in binephrectomized rats, suggesting that the two drugs had a direct effect on smooth muscle K+ (86Rb) permeability. Decreased ex vivo smooth muscle 22Na efflux induced by oral cyclothiazide and triamterene is probably secondary to their renal actions, since there was no effect in binephrectomized rats.

Effects of angiotensin II on ionic fluxes in rat myometrium.

1. The action of angiotensin II (At II) on 24Na, 42K and 36 Cl fluxes was examined using longitudinal strips of rat myometrium as an experimental model. 2. In normally polarized muscles, At II 3.3 x 10(-6)M, a concentration 10 times higher than necessary to produce a maximal contraction of the muscle, increases 42K and 36 Cl efflux rates as well as 42K uptake. The action of At II on 42K and 36Cl effluxes is concentration-dependent. Under the same conditions 24Na efflux is not affected by At II, but a significant increase of 24Na uptake is obtained. In order to know whether the observed effects were membrane potential dependent, we reexamined the action of the peptide in preparations previously depolarized by a 101 mM K+ solution (K+ replacing Na+). In depolarized preparations, At II 3.3 x 10(-6)M still increases 24Na uptake, but the effects previously observed on 42K and 36Cl fluxes in normally polarized preparations are suppressed. It is concluded that At II produces a primary increase in the membrane permeability to Na+ and that the stimulation of 42K and 36Cl fluxes induced by At II in myometrial strips appears to be mainly potential dependent.