Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.11.18 (MAP)
 7,412 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The present study was designed to determine the pharmacologic effects of rat atrial natriuretic factor (r-ANF; 250 ng/kg/min), endothelin-3 (ET-3; 340 ng/kg/min), and combined r-ANF and ET-3 infusion on cardiac hemodynamics and renal function in anesthetized rats. The change in mean arterial pressure (delta MAP) was 13 +/- 2 mm Hg during ET-3 infusion alone. Delta MAP was -9 +/- 2 mm Hg during r-ANF infusion alone. Combined infusion of ET-3 and r-ANF resulted in a change in MAP of -7 +/- 3 mm Hg. The decrease in MAP during combined infusion of ET-3 and r-ANF occurred due to a decrease in cardiac output. Infusion of r-ANF did not block the cardiac output. Infusion of r-ANF did not block the ET-3-induced increase in total peripheral resistance (TPR). Infusion of r-ANF alone resulted in an 11-fold increase in urinary sodium excretion. ET-3 infusion completely blocked the ANF-induced natriuresis in part by markedly decreasing the glomerular filtration rate (GFR). ET-3 or r-ANF infusion alone resulted in two- or eightfold increases, respectively, in circulating r-ANF levels compared to vehicle alone. However, combined infusion of r-ANF and ET-3 resulted in a dramatic 27-fold increase in circulating r-ANF when compared to levels obtained during vehicle infusion alone. The present study demonstrates that at pharmacologic levels, r-ANF blocks the pressor action of ET-3 by decreasing cardiac output rather than TPR. Furthermore, ET-3 blocks the natriuretic action of r-ANF, partly by decreasing GFR.
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PMID:Atrial natriuretic factor blocks the pressor action of endothelin. 170 77

Circulating epinephrine alters atrial natriuretic factor (ANF) and arginine vasopressin (AVP) secretion, and all three hormones influence renal function. To quantify the relationships among fetal plasma epinephrine levels, fetal ANF and AVP secretion, and fetal renal function, six chronically catheterized fetal lambs (132 +/- 1 days gestation) received successive 40-min epinephrine infusions (0.1, 0.4, and 1.8 micrograms.min-1.kg-1). The second epinephrine infusion dose evoked significant increases in urine flow (V; 0.7 +/- 0.2 to 1.2 +/- 0.2 ml/min), free water clearance (CH2O; 0.3 +/- 0.1 to 0.7 +/- 0.1 ml/min), glomerular filtration rate (GFR; 3.9 +/- 0.7 to 5.4 +/- 0.8 ml/min), fractional water excretion (V/CH2O; 19 +/- 3 to 25 +/- 2%), mean arterial pressure (MAP; 45 +/- 3 to 51 +/- 4 mmHg), and a 94% increase in plasma ANF levels. A fourfold increase in the infusion dose significantly increased osmolar clearance (0.3 +/- 0.1 to 0.6 +/- 0.1 ml/min), sodium excretion (28 +/- 8 to 53 +/- 13 mueq/min), and plasma AVP levels (2.4 +/- 0.5 to 6.4 +/- 2.4 pg/ml) with no additional effect on V, CH2O, GFR, V/GFR, MAP, or plasma ANF levels. Urine osmolality and fractional sodium excretion did not change in response to epinephrine infusion. Our results demonstrate that epinephrine infusion stimulates fetal ANF secretion and to a lesser extent AVP secretion and significantly influences fetal renal function.
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PMID:Ovine fetal renal and hormonal responses to changes in plasma epinephrine. 182 60

Recent work suggests that hypophysectomized (HYPOX) rats show low levels of atrial natriuretic factor (ANF) and an attenuated diuresis and natriuresis to blood volume expansion. The purpose of this was (i) to examine the effect of various hormone replacements on ANF and renal excretion in HYPOX rats and (ii) to compare the renal responses to exogenous ANF in intact and HYPOX rats. Groups of rats received subcutaneous pellet implant of either dexamethasone (DEX), thyroxine (T4), or a placebo. Approximately 1 week later, they were anesthetized and subjected to a 20% blood volume expansion. DEX rats had a higher mean arterial pressure than placebo-treated rats while both MAP and heart rate were higher in T4 rats. Only the DEX rat showed augmented renal responses to volume expansion while no group showed significant changes in plasma ANF concentration during volume expansion. In a second series, groups of HYPOX rats received renal capsular transplants of either six hemi-pituitaries or six pieces of muscle which markedly raised serum prolactin levels in the hemi-pituitary group. The hemi-pituitary rats showed a greater diuresis and natriuresis during volume expansion than the muscle group and also showed a transient increase in plasma ANF. In addition, groups of either intact or HYPOX rats were anesthetized and received intravenous bolus injections of ANF. Both intact and HYPOX rats showed a very similar diuresis and natriuresis to exogenous ANF. However, potassium excretion was markedly reduced in HYPOX rats. The results show that DEX augments the renal responses to volume expansion by some mechanism which does not involve changes in plasma ANF. Thyroxine increases mean arterial pressure and heart rate in HYPOX rats but does not augment the renal or ANF responses to volume expansion. Chronic elevations in prolactin increase the renal response to volume expansion. Finally, the kidneys of HYPOX rats are capable of increasing sodium and water output in response to large doses of exogenous ANF.
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PMID:Studies on the role of the pituitary in the control of atrial natriuretic factor secretion and sodium excretion. 214 22

The effect on single-unit activity, arterial pressure, and heart rate of a microinjection of atrial natriuretic factor (ANF) into 78 histologically verified sites in the nucleus tractus solitarii (NTS) was investigated in rats. Injections of 50 nl of 10(-7) M ANF excited 34 neurons (44%), mainly localized at the level of the obex, inhibited 15 (19%), and had no effect on the remaining 29 (37%). The increase in firing frequency of the 34 excited neurons was always followed by a decline in mean arterial pressure [MAP, -10.6 +/- 1.8 (SE) mmHg; P less than 0.01] and heart rate [HR, -9.6 +/- 3.1 (SE) beats/min; P less than 0.05]. When injections of ANF caused either no effect or inhibition of single-unit activity, no changes in either MAP or HR were observed. Single units excited by injections of ANF were also excited by activation of arterial baroreceptors and inhibited by baroreceptor unloading. Control injections of an inactive peptide analogue of ANF or of vehicle never produced any effects on neuronal firing frequency or on MAP and HR. Similar results were obtained from animals paralyzed and artificially ventilated. These results support the hypothesis that ANF plays a role in the chemical transmission of baroreceptor information within the NTS.
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PMID:Neuronal and cardiovascular responses to ANF microinjected into the solitary nucleus. 252 81

Patients with untreated essential hypertension had significantly higher plasma atrial natriuretic factor (ANF) levels (92.9 +/- 12.9 pg/ml, mean +/- SE) than those of age-matched controls (37.8 +/- 6.0 pg/ml; p less than 0.01). Plasma ANF levels in essential hypertensive patients showed a significant positive correlation with mean arterial pressure (MAP; r = 0.46, p less than 0.05) and an inverse correlation with plasma renin activity (PRA; r = -0.43, p less than 0.05). Plasma ANF levels after medication showed significant correlation with the decrease in MAP (r = 0.565, p less than 0.05). Patients with primary aldosteronism had significantly higher plasma ANF levels (122.4 +/- 30.2 pg/ml, n = 8) than those of controls (p less than 0.05). The levels returned to normal after extirpation of adrenal tumors. The response of plasma ANF levels in patients with primary aldosteronism to volume expansion with infusion of 2 L of physiological saline in 2 hours was greater than in controls. Such exaggerated response disappeared after surgical treatment. Infusion of angiotensin II (Ang II; 20 ng/kg/min) or norepinephrine (200 ng/kg/min) for 30 minutes to normal volunteers (n = 5) resulted in a rise in MAP (24.9 +/- 3.3 and 15.8 +/- 4.4 mm Hg, respectively) and a twofold increase in plasma ANF level. Infusion of the Ang II antagonist [Sar1, Ile8]Ang II (600 ng/kg/min) for 30 minutes, resulted in a rise in MAP (18.8 +/- 2.1 mm Hg) and more than a twofold increase in plasma ANF level in patients with essential hypertension (n = 6).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Atrial natriuretic factor in essential hypertension and adrenal disorders. 296 1

Atrial natriuretic factor (ANF) has been suggested as a putative neurotransmitter in central pathways involved in the control of the cardiovascular system. To investigate this possibility, 50 nl of 10(-7) M ANF were microinjected into discrete sites in the nucleus of the tractus solitarius (NTS) where baro- and chemoreceptor afferents terminate. Injections into 36 of a total of 66 sites in the NTS of paralyzed artificially ventilated Wistar rats under urethan anesthesia were found to produce a significant decline in heart rate [HR; -9.2 +/- 2.9 (SE) beats/min, P less than 0.05] and mean arterial pressure [MAP; -11.1 +/- 1.2 (SE) mmHg, P less than 0.01]. Similar responses were also present in anesthetized animals breathing spontaneously. Microinjection of an inactive peptide analogue or of saline did not produce cardiovascular changes. It was also found that ANF injection into the cuneate nucleus (20 of 38 sites) and the spinal trigeminal complex (28 of 42 sites) produced a decrease in MAP and HR that were of the same magnitude as those seen in the NTS. Injections of ANF into the medial longitudinal fasciculus (n = 22), hypoglossal nucleus (n = 9), area postrema (n = 16), and dorsal motor nucleus of the vagus (n = 11) did not change HR or MAP. These results suggest that ANF may serve as a neurotransmitter involved in cardiovascular reflexes mediated by specific nuclei in the dorsal medulla.
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PMID:Cardiovascular responses to microinjection of ANF into dorsal medulla of rats. 296 95

Previous studies of the atrial stretch-atrial natriuretic factor (ANF) relationship during pregnancy have employed volume expansion and measured only right atrial pressure (RAP). Consequently, we studied nonpregnant (n = 7) and 115- to 125-day pregnant (n = 7) sheep and assessed the ANF response to changes of RAP and left atrial pressure (LAP) induced by graded balloon inflation. Ewes prepared with vascular catheters and atrial balloons were studied after recovery from preparatory surgical procedures. The basal levels of mean arterial pressure (MAP, 83 +/- 3 mmHg), RAP (2.1 +/- 0.7 mmHg), LAP (4.7 +/- 0.9 mmHg), and heart rate (HR, 102 +/- 6 beats/min) were similar in nonpregnant and pregnant sheep. Pregnancy also resulted in elevation of ANF concentration from 25 +/- 6 to 57 +/- 4 fmol/ml. With right atrial distension, the RAP-ANF relationships were similar in both nonpregnant and pregnant sheep, with a 10-mmHg increase in RAP increasing ANF by an average of 95 +/- 9 fmol/ml. In nonpregnant sheep, the LAP-ANF relationship was more responsive than RAP-ANF because a 10-mmHg increase in LAP resulted in a 193 +/- 10 fmol/ml increase in ANF. Moreover, during pregnancy, the LAP-ANF relationship was significantly more sensitive because a 10-mmHg increase in LAP resulted in a 433 +/- 15 fmol/ml elevation of ANF. These data demonstrate that plasma ANF levels are more responsive to distension of the left atria than to the right. More importantly, the ANF response to left, but not right, atrial distension is enhanced by pregnancy.
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PMID:Control of atrial natriuretic factor by right and left atrial distension in pregnant sheep. 761 17

Atrial natriuretic peptide (ANP) has been shown to reverse functional impairment in ischemic acute renal failure (ARF). To prolong and/or to enhance the effects of peptide, in this investigation dopamine (D) (3 micrograms/kg BW/min) was applied together with ANP (100 ng/kg BW/min) after 90 min unilateral renal artery occlusion in anesthetized dogs. ANP significantly increased creatine clearance, filtration fraction, diuresis, sodium excretion, sodium reabsorption, and free water clearance, as in postinfusion period only V remained elevated. D alone did not effect renal function beneficially. ANP+D improved kidney function impairment to a level comparable with that of ANP alone, but V and UNa.V remained increased in the postinfusion period. MAP was elevated during ANP+D infusion as compared to ANP alone and was sustained to the end of the experiment. We conclude that D does not potentiate the positive effects of ANP on postischemic kidney, but prolongs its action on UNa.V, possibly by maintenance of high MAP after renal ischemia.
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PMID:Atrial natriuretic peptide and dopamine in a dog model of acute renal ischemia. 797 98

Shortly after birth, cardiac myocytes lose the ability to divide, and, in adult animals, heart muscle grows by a process of cellular hypertrophy where each individual cell gets larger. We have previously shown that activated Ras protein can induce markers of the hypertrophic phenotype, including atrial natriuretic factor (ANF) expression and organization of contractile proteins, and that Ras is at least partially required for the hypertrophic effect of phenylephrine. In the present study, we examine the requirement for the mitogen-activated protein kinases (MAP kinases) in the hypertrophic response induced by phenylephrine. We find that phenylephrine treatment results in the activation of the MAP kinases and that this activity is required for transactivation of the fos, ANF, and MLH promoters. However, inhibition of MAP kinases does not prevent phenylephrine-induced organization of actin. These results suggest that the signal transduction pathways leading to different hypertrophic responses diverge upstream of the MAP kinases but possibly downstream of Ras.
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PMID:Mitogen-activated protein kinases mediate changes in gene expression, but not cytoskeletal organization associated with cardiac muscle cell hypertrophy. 808 86

In order to clarify the mechanisms of interaction between endothelin-1 (ET-1) and cyclic AMP (cAMP) or cyclic GMP (cGMP), we examined the effects of cAMP or cGMP on ET-1-induced activation of mitogen-activated protein kinase (MAPK), one of the key enzymes in the signal transduction of ET-1, in cultured rat mesangial cells. ET-1 was able to activate both p42 and p44 MAP kinases in a dose-dependent manner. Cell permeable analogues of cAMP and cGMP, dibutylyl cAMP (BT2-cAMP) and 8 bromo cGMP (8br-GMP), significantly inhibited ET-1-induced activation of MAPK. Atrial natriuretic peptide (ANP), which increased cellular cGMP, was able to inhibit ET-1-induced activation of MAPK in a dose-dependent manner, while c-ANP, an analogue specific to the clearance receptors of ANP, exerted no effect. These results indicate that cAMP and cGMP could modulate the action of ET-1 in mesangial cells at a step of the activation of MAPK.
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PMID:Cyclic nucleotides attenuate endothelin-1-induced activation of mitogen-activated protein kinase in cultured rat mesangial cells. 857 39


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