Relation between intestinal motility and mesenteric blood flow in the conscious dog

1984 ◽  
Vol 246 (2) ◽  
pp. G108-G113 ◽  
Author(s):  
J. Fioramonti ◽  
L. Bueno
Keyword(s):  
Blood Flow ◽  
Mesenteric Artery ◽  
Intestinal Content ◽  
Flow Profile ◽  
Mesenteric Blood Flow ◽  
Flow Probe ◽  
Postprandial Period ◽  
Conscious Dog ◽  
Cyclic Variations ◽  
Electromagnetic Flow Probe

Blood flow in a mesenteric artery and electrical activity of the corresponding segment of jejunum or ileum were simultaneously measured in eight conscious dogs. Each was fitted chronically with an electromagnetic flow probe and transparietal electrodes. In some dogs an intestinal cannula was placed cephalad to the segment investigated. Continuous 24-h records were obtained in each dog receiving a daily meal. Jejunal blood flow increased after the meal, decreased progressively during the postprandial period (7-12 h), and then exhibited cyclic variations associated with the occurrence of migrating myoelectric complexes (MMCs) during the next 6-10 h. The ileal blood flow increased, then remained high and nearly constant during the postprandial disorganization of the MMC pattern, and exhibited cyclic variations associated with all MMCs even when the dog was fasted for 48 h. Cyclic variations in blood flow were abolished when the intestinal content was drained through the cannula. It is concluded that in the conscious dog the blood flow profile in a mesenteric artery is associated with the motor profile of the segment. This association is due to the presence of digestive matter, probably nutrients in the jejunum and bile in the ileum.

Effect of secretin and cholecystokinin on small intestinal blood flow distribution

1975 ◽  
Vol 229 (5) ◽  
pp. 1365-1370 ◽  
Author(s):  
JW Fara ◽  
KS Madden
Keyword(s):  
Blood Flow ◽  
Mesenteric Artery ◽  
Flow Distribution ◽  
Jejunal Mucosa ◽  
Blood Flow Distribution ◽  
Mesenteric Blood Flow ◽  
Apparent Relationship ◽  
Percent Increase ◽  
Intestinal Segments ◽  
Small Intestinal

The relative blood flow distribution within the small intestine of anesthetized cats was investigated during resting conditions and when superior mesenteric blood flow was increased 15--85% by the intravenous infusion of secretin, cholecystokinin (CCK), or isoproterenol. Radioactive microspheres of 15 mum diameter were injected into the superior mesenteric artery and shortly thereafter intestinal segments were removed and dissected into mucosal, submucosal, and muscularis fractions. Tissue weights and the radioactivity of each were determined. During secretin-induced mesenteric vasodilatation there was a significant redistribution of blood away from the jejunal mucosa to the submucosa. During CCK and isoproterenol infusions there were significant increases in mucosal and decreases in submucosal blood flow. No significant changes were observed in muscularis flow. There was no apparent relationship between the percent increase in SMBF and the relative blood flow distribution changes observed. The results indicate that while secretin, CCK, and isoproterenol increase superior mesenteric blood flow, they also affect blood flow distribution within the mucosa and submucosa.

Endothelin resets renal blood flow autoregulatory efficiency during acute blockade of NO in the rat

2001 ◽  
Vol 281 (6) ◽  
pp. F1132-F1140 ◽  
Author(s):  
R. Kramp ◽  
P. Fourmanoir ◽  
N. Caron
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Receptor Subtypes ◽  
Receptor Blockade ◽  
Flow Probe ◽  
Relative Contribution ◽  
No Inhibition ◽  
Electromagnetic Flow Probe ◽  
Bq 610

First published August 15, 2001; 10.1152/ajprenal.00078.2001.—Renal blood flow (RBF) autoregulatory efficiency may be enhanced during NO inhibition in the rat, as recently reported. Under these conditions, endothelin (ET) synthesis and release may be increased. Our purpose was therefore to determine the role of ET in RBF autoregulatory changes induced by NO inhibition. To address this point, ETA/B receptors were blocked in anesthetized rats with bosentan, or selectively with BQ-610 or BQ-788. NO synthesis was inhibited with N G-nitro-l-arginine methyl ester (l-NAME). Mean arterial pressure (MAP) was decreased after bosentan (−10 mmHg; P < 0.01) or increased after l-NAME (25 mmHg; P < 0.001). RBF measured with an electromagnetic flow probe was reduced byl-NAME (−50%) and by BQ-788 (−24%). The pressure limits of the autoregulatory plateau (PA ∼100 mmHg) and of no RBF autoregulation (Po ∼80 mmHg) were significantly lowered by 15 mmHg after l-NAME but were unchanged after bosentan, BQ-610, or BQ-788. During NO inhibition, autoregulatory resetting was completely hindered by bosentan (PA ∼100 mmHg) and by ETB receptor blockade with BQ-788 (PA ∼106 mmHg), but not by ETA receptor blockade with BQ-610 (PA ∼85 mmHg). These results suggest that the involvement of ET in the RBF autoregulatory resetting occurs during NO inhibition, possibly by preferential activation of the ETB receptor. However, the relative contribution of ET receptor subtypes remains to be further specified.

Independent control of mucosal and total airway blood flow during hypoxemia

1991 ◽  
Vol 71 (1) ◽  
pp. 223-228 ◽  
Author(s):  
S. Elsasser ◽  
W. M. Long ◽  
H. J. Baier ◽  
A. D. Chediak ◽  
A. Wanner
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Blood Circulation ◽  
Mucosal Blood Flow ◽  
Systemic Arterial Pressure ◽  
Microvascular Network ◽  
Flow Probe ◽  
Electromagnetic Flow Probe ◽  
6 Hydroxydopamine ◽  
Tracheal Mucosal Blood Flow

In the larger airways, the blood circulation forms a subepithelial (mucosal) and outer (peribronchial) microvascular network. This raises the possibility that blood flow in these two networks is regulated independently. We used hypoxemia as a stimulus to induce changes in tracheal mucosal blood flow normalized for systemic arterial pressure (Qtr n) measured with an inert soluble gas technique and total bronchial blood flow (Qbr) and normalized Qbr (Qbrn) measured with an electromagnetic flow probe in anesthetized sheep. Fifteen minutes of hypoxemia [PO2 40 +/- 7 (SD) Torr] decreased mean Qtr n from 1.1 +/- 0.4 to 0.8 +/- 0.4 ml.min-1.mmHg-1.10(2) (-27%; P less than 0.05; n = 7) and increased mean Qbr n from 12.1 +/- 3.2 to 17.1 +/- 5.4 ml.min-1.mmHg-1.10(2) (+41%; P less than 0.05; n = 6). The rise in Qbr correlated with cardiac output (r = 0.68; P less than 0.05). Phentolamine pretreatment (0.1 mg/kg iv) blunted the hypoxemia-related decrease of mean Qtr n (-8%; P = NS). Tyramine (2.5 mg) applied locally to the trachea decreased mean Qtr n significantly after 30 and 45 min by 31 and 19%, respectively (P less than 0.05). 6-Hydroxydopamine (0.2 mg 4 times for 1 h locally applied) prevented the hypoxemia-induced as well as local tyramine-induced decrease in mean Qtr n (0 and 0%).(ABSTRACT TRUNCATED AT 250 WORDS)

Local control of mesenteric blood flow by the renin-angiotensin system

1988 ◽  
Vol 255 (3) ◽  
pp. G267-G274
Author(s):  
A. Suvannapura ◽  
N. R. Levens
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Mesenteric Artery ◽  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Ang Ii ◽  
Volume Depletion ◽  
Mesenteric Blood Flow ◽  
Direct Role ◽  
Mesenteric Circulation

The purpose of this study is to determine whether locally acting angiotensin II (ANG II) plays a direct role in the control of mesenteric blood flow after volume depletion in the anesthetized dog. Infusion of the ANG II receptor antagonist saralasin into the mesenteric artery at doses between 0.05 and 0.1 microgram.kg-1.min-1 attenuated the reduction in renal blood flow produced by intrarenal injection of ANG II. In contrast, infusion of saralasin at 0.01 microgram.kg-1.min-1 did not affect the change in renal blood flow produced by ANG II, indicating that at this dosage the antagonist did not leave the mesenteric circulation in pharmacologically significant quantities. ANG II produced a dose-dependent decrease in splanchnic blood flow when injected into the mesenteric artery. Simultaneous infusion of 0.01 microgram.kg-1.min-1 saralasin into the mesenteric artery blocked the action of up to 1 ng ANG II by 80%. Infusion of saralasin at 0.01 microgram.kg-1.min-1 into the mesenteric artery of hemorrhaged animals increased mesenteric blood flow without significantly affecting renal blood flow, blood pressure, or plasma renin activity. These data demonstrate that saralasin can be localized to the mesenteric circulation at a dose capable of inhibiting angiotensin action and that endogenous ANG II plays a direct, physiologically important local role in controlling splanchnic resistance after volume depletion.

Formation of angiotensin III from [des-Asp1]angiotensin I in the mesentric vasculature

1979 ◽  
Vol 237 (2) ◽  
pp. H218-H223 ◽  
Author(s):  
J. M. Sexton ◽  
S. L. Britton ◽  
W. H. Beierwaltes ◽  
M. J. Fiksen-Olsen ◽  
J. C. Romero
Keyword(s):  
Blood Flow ◽  
Mesenteric Artery ◽  
Enzyme Inhibitor ◽  
Enzymatic Conversion ◽  
Converting Enzyme ◽  
Angiotensin I ◽  
Mesenteric Blood Flow ◽  
Angiotensin Iii ◽  
Anesthetized Dogs ◽  
Dose Dependent

The effects of [des-Asp1]angiotensin I and angiotensin III on mesenteric blood flow were compared in 15 pentobarbital-anesthetized dogs. These agonists were administered as bolus injections directly into the vasculature supplied by the superior mesenteric artery. Both [des-Asp1]angiotensin I and angiotensin III produced dose-dependent decreases in mesenteric blood flow, with angiotensin III being more potent than [des-Asp1]angiotensin I at all doses tested. The constrictor responses to [des-Asp1]angiotensin I were markedly attenuated in the presence of an angiotensin-converting enzyme inhibitor (SQ20881); SQ20881 did not alter responses to angiotensin III or norepinephrine. The administration of [Ile7]angiotensin III (an angiotensin III antagonist) attenuated the responses to both [des-Asp1]angiotensin I and angiotensin III, without altering the responses to norepinephrine. These results suggest that the decrease in mesenteric blood flow produced by [des-Asp1]angiotensin I is largely caused by its local enzymatic conversion to angiotensin III. This conversion in one transit through the mesenteric vasculature is approximately 24%.

Myocardial blood flow and function during gradual coronary occlusion in awake dog

1983 ◽  
Vol 244 (1) ◽  
pp. H60-H67 ◽  
Author(s):  
R. C. Hill ◽  
L. H. Kleinman ◽  
W. H. Tiller ◽  
W. R. Chitwood ◽  
J. C. Rembert ◽  
...  
Keyword(s):  
Blood Flow ◽  
Coronary Artery ◽  
Coronary Occlusion ◽  
Treadmill Exercise ◽  
Regional Blood Flow ◽  
Mean Flow ◽  
Flow Probe ◽  
Circumflex Artery ◽  
Electromagnetic Flow Probe ◽  
And Function

The purpose of this study was to correlate dimensions and transmural blood flow in a segment of myocardium supplied by a coronary artery undergoing gradual closure. Nine adult dogs were instrumented with an electromagnetic flow probe, pneumatic occluder, and an ameroid constrictor on the circumflex coronary artery. Ultrasonic crystals were implanted 10 mm from the external surface of the left ventricle in a segment perfused by the circumflex artery. Regional blood flow was determined with 7- to 10-microns radiolabeled microspheres. Data were collected in the awake state at rest before closure began (control), during partial closure, and immediately after total closure. Seven of the nine animals were studied after occlusion during treadmill exercise. During both partial and total closure at rest the rate and extent of systolic shortening as well as the transmural blood flow were unchanged from control. During treadmill exercise mean flow increased. However, flow was redistributed away from the inner two layers causing deterioration in both the rate and extent of shortening of this segment. These data suggest that, although regional myocardial function and flow can be maintained at rest by the immature canine collateral circulation, these parameters are impaired markedly during augmented flow with exercise.

Prostaglandins: renal vascular responses to bradykinin, histamine, and nitroglycerine

1978 ◽  
Vol 234 (4) ◽  
pp. H496-H502 ◽  
Author(s):  
L. P. Feigen ◽  
B. M. Chapnick ◽  
J. E. Flemming ◽  
P. J. Kadowitz
Keyword(s):  
Blood Flow ◽  
Arachidonic Acid ◽  
Cyclooxygenase Inhibitors ◽  
Flow Probe ◽  
Vascular Responses ◽  
Vasodilator Activity ◽  
Before And After ◽  
Anesthetized Dogs ◽  
Electromagnetic Flow Probe ◽  
Renal Vascular

A study was undertaken to evaluate the effects of inhibitors of prostaglandin (PG) synthesis on renal vascular responses to several renal vasodilators in anesthetized dogs. Indomethacin (IND) and meclofenamate (MEC), two dissimilar cyclooxygenase inhibitors were used. An electromagnetic flow probe was placed on the renal artery and a needle was inserted proximal to the probe. Injections of bradykinin, histamine, nitroglycerine, and arachidonic acid (AA) were given before and after administration of IND or MEC, 2.5 mg/kg body wt. In each experiment, inhibition of PG synthesis was estimated by reduction of vasodilator activity following AA injection. Although renal vascular resistance increased slightly after IND or MEC, elevations of renal blood flow in response to injections of bradykinin and nitroglycerine were not affected by PG synthesis inhibitors, whereas percent responses to histamine were enhanced by IND but not MEC. In addition, the action of 5 mg/kg IND on responses to injections and infusions of bradykinin was evaluated. No decrease in vasodilator activity following the kinin was detected in these studies. These results demonstrate that renal vascular responses to bradykinin, histamine, and nitroglycerine were not dependent on endogenously produced products of cyclooxygenase (e.g., prostaglandins) in the kidney of the anesthetized dog.

Mammary blood flow during experimental Escherichia coli endotoxin induced mastitis in goats and cows

1977 ◽  
Vol 44 (3) ◽  
pp. 433-440 ◽  
Author(s):  
G. Dhondt ◽  
C. Burvenich ◽  
G. Peeters
Keyword(s):  
Escherichia Coli ◽  
Heart Rate ◽  
Blood Flow ◽  
Cell Count ◽  
Total Cell ◽  
Total Cell Count ◽  
Flow Probe ◽  
Lactating Goats ◽  
Acute Mastitis ◽  
Electromagnetic Flow Probe

SummaryThe effect of intramammary infusion of Escherichia coli endotoxin upon mammary blood flow was studied in lactating goats and cows. Blood flow was recorded by means of an electromagnetic flow probe chronically implanted around one mammary artery.Endotoxin mastitis was always accompanied by a significant increase in mammary blood flow, characterized by 2 conspicuous peaks. The flow returned to control values by the thirteenth hour after infusion. Other symptoms of acute mastitis were: fever, increased heart rate, swelling, heat and pain of the gland, increased chloride and total cell count in milk.

Direct Fick application for measurement of cardiac output in rat

1976 ◽  
Vol 40 (5) ◽  
pp. 849-853 ◽  
Author(s):  
G. M. Walsh ◽  
M. Tsuchiya ◽  
E. D. Frohlich
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Electromagnetic Flowmeter ◽  
Flow Probe ◽  
Electromagnetic Flow ◽  
Cardiac Output Determination ◽  
Electromagnetic Flow Probe ◽  
Simultaneous Comparison ◽  
Cardiac Output Measurements

The direct Fick procedure for cardiac output determination in rat was validated by simultaneous comparison with electromagnetic flowmeter techniques. Significant coefficients of correlation were obtained between absolute cardiac output values (r = 0.789, P less than 0.001), increases (r = 0.768, P less than 0.001) and decreases (r = 0.672, P less than 0.01) in cardiac output detected by the two methods. As demonstrated in other species, cardiac output values of the Fick procedure in the rat were between 40 and 58% greater than respective electromagnetic flow probe values; however, percent changes in cardiac output obtained by the two methods were similar. The larger values of cardiac output obtained by the direct Fick method may be related, to a great extent, to the distribution of blood flow to the coronary and bronchial circulations. Fick cardiac output measurements were reproducible within rats, and the degree of variation in values among rats was similar to that obtained with the flowmeter procedure. The result indicate that the Fick meth od provides a valid estimation of cardiac output in the rat, with the ability to detect moderate changes (22–36%) in cardiac output.

scholarly journals Renal responses to intra-arterial administration of adrenomedullin in dogs

1996 ◽  
Vol 270 (1) ◽  
pp. F200-F205 ◽  
Author(s):  
D. S. Majid ◽  
P. J. Kadowitz ◽  
D. H. Coy ◽  
L. G. Navar
Keyword(s):  
Blood Flow ◽  
Partial Recovery ◽  
Electrolyte Excretion ◽  
Arterial Infusion ◽  
Flow Probe ◽  
Medullary Blood Flow ◽  
Anesthetized Dogs ◽  
Electromagnetic Flow Probe ◽  
Renal Vascular ◽  
Renal Responses

The present study was undertaken to evaluate the renal responses to intra-arterial infusion (12.5 pmol.kg-1.min-1) for 30 min of adrenomedullin (ADM) in denervated kidneys of anesthetized dogs (n = 8). Total renal blood flow (RBF) was measured with an electromagnetic flow probe, and two single-fiber laser-Doppler needle flow probes were used to measure relative changes in cortical (CBF) and medullary blood flow (MBF). ADM administration resulted in decreases in renal vascular resistance (32.3 +/- 4.9 to 22.3 +/- 3.0 mmHg.ml-1.min.g) and increases in RBF (4.5 +/- 0.5 to 6.0 +/- 0.6 ml.min-1.g-1), CBF (33 +/- 1.3%, n = 41, and MBF (32 +/- 5.7%, n = 5) without changes in glomerular filtration rate. There were also substantial increases in urine flow (11.3 +/- 1.9 to 28 +/- 4.8 microliters.min-1.g-1), as well as in sodium excretion (1.8 +/- 0.2 to 4.2 +/- 0.6 microliter.min-1.g-1). After cessation of ADM infusion, partial recovery of these responses was observed within a 30-min period. Responses to ADM were attenuated during inhibition of nitric oxide (NO) synthesis by nitro-L-arginine (50 micrograms.kg-1.min-1). These findings indicate that renal vasodilator, diuretic, and natriuretic responses to ADM may be mediated by the release of endogenous NO and suggest that ADM could play a role in regulating water and electrolyte excretion by the kidney.

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