Effect of opioid peptides on the regional hemodynamics in conscious rats

1988 ◽  
Vol 106 (2) ◽  
pp. 1071-1074
Author(s):  
E. A. Martynova ◽  
O. S. Medvedev
Keyword(s):  
Opioid Peptides ◽  
Conscious Rats ◽  
Regional Hemodynamics

Systemic and regional hemodynamics in conscious rats during 24-hour antiorthostasis

1990 ◽  
Vol 109 (1) ◽  
pp. 24-27
Author(s):  
E. Yu. Bychkova ◽  
E. R. Martynova ◽  
O. S. Medvedev ◽  
V. P. Krotov ◽  
F. E. Meertsuk
Keyword(s):  
Conscious Rats ◽  
Regional Hemodynamics

Role of site of microsphere injection and catheter position on systemic and regional hemodynamics in rat

1984 ◽  
Vol 247 (1) ◽  
pp. H35-H39 ◽  
Author(s):  
I. Kobrin ◽  
M. B. Kardon ◽  
W. Oigman ◽  
B. L. Pegram ◽  
E. D. Frohlich
Keyword(s):  
Blood Flow ◽  
Coronary Blood Flow ◽  
Coronary Flow ◽  
Left Ventricular ◽  
Ventricular Catheter ◽  
Catheter Position ◽  
Flow Measurements ◽  
Conscious Rats ◽  
Anesthetized Rats ◽  
Regional Hemodynamics

The influences of the site of microsphere injection (intra-atrial vs. intraventricular) and positioning of the left ventricular catheter (aortoventricular vs. atrioventricular) on systemic, renal, and coronary hemodynamics were evaluated in anesthetized rats. The effect of anesthesia on aortoventricular catheter positioning was also evaluated. In anesthetized and open-chest preparations, the systemic and renal hemodynamics were not affected by catheter position or site of microsphere injection; however, myocardial blood flow was dependent on these variables. Variations in coronary blood flow were significantly greater when the catheter was in the aortoventricular position (34 +/- 3%) than with an atrioventricular catheter (11 +/- 2%, P less than 0.01), irrespective of whether the microspheres were injected into the atrium or ventricle. Comparison of anesthetized and conscious rats with aortoventricular catheter indicated lesser variability in coronary blood flow in the conscious rats (P less than 0.01). Therefore, the greater variability of coronary flow measurements in anesthetized rats was caused by the position of the cardiac catheter in the aortoventricular route. However, the variability caused by the aortoventricular catheter was much less in conscious rats. Therefore, coronary flow hemodynamic measurements (microsphere technique) are less variable when they are made in conscious rats.

Influence of opioid peptides on release from vasopressin and oxytocin neurones of the hypothalamoneurohypophyseal system: effects of naloxone in the conscious rat

1990 ◽  
Vol 68 (5) ◽  
pp. 568-574 ◽  
Author(s):  
Savio W. T. Cheng ◽  
Edward F. O'Connor ◽  
William G. North
Keyword(s):  
Plasma Concentration ◽  
Opioid Peptides ◽  
Plasma Concentrations ◽  
Plasma Osmolality ◽  
Plasma Sodium ◽  
Endogenous Opioid ◽  
Salt Loading ◽  
Conscious Rats ◽  
Basal Plasma ◽  
Acute And Chronic Treatments

We examined the effects of acute and chronic treatments with naloxone on release of vasopressin and oxytocin from the hypothalamoneurohypophyseal system (HNS) in conscious, chronically instrumented Long–Evans rats. Plasma concentrations of vasopressin-associated neurophysin and oxytocin-associated neurophysin were evaluated before and during an intravenous infusion of 18% saline at 100 μL∙kg−1 body weight∙min−1 for 60 min. Acute treatment with naloxone (2.75 μmol/kg, intravenous) did not measurably alter basal plasma osmolality or vasopressin-associated neurophysin concentration, but it caused a three-fold rise in basal plasma oxytocin-associated neurophysin concentration (16 ± 2 to 46 ± 3 fmol/mL, p < 0.005). Chronic treatment with naloxone (13.75 μmol/day, subcutaneous pellets) increased plasma osmolality (292 ± 1 to 300 ± 2 mosmol/kg H2O, p < 0.01) by day 5, but it had no measurable effects on basal vasopressin- or oxytocin-associated neurophysin concentration. There were also no significant differences in plasma sodium concentration (144.8 ± 1.1 vs. 142.2 ± 1.4 mequiv./L) under both conditions. Acute and chronic treatments with naloxone accompanied by salt loading produced a five- and four-fold decrease in the rates that plasma concentration of vasopressin-associated neurophysin changed with plasma osmolality, compared with untreated salt-loaded control rats. For oxytocin secretion from the HNS, both treatments accompanied by salt loading substantially decreased the threshold for changes in relation to plasma osmolality; the rise in plasma concentration of oxytocin-associated neurophysin was similar at all levels of hyperosmotic stimulation. A strongly correlated relationship between plasma oxytocin-associated neurophysin and plasma osmolality (r = 0.739) found for control animals became poorly correlated following treatments (acute, r = 0.173; chronic, r = −0.079). Our results suggest that in conscious rats, endogenous opioid peptides enhance the secretion of vasopressin from neurones of the HNS in response to hyperosmotic stimulation but inhibit both basal and stimulated release of oxytocin.Key words: naloxone, vasopressin, oxytocin, neurophysin, conscious rats.

Activation of afferent renal nerves by intrarenal bradykinin in conscious rats

1984 ◽  
Vol 247 (6) ◽  
pp. R1003-R1008 ◽  
Author(s):  
J. F. Smits ◽  
M. J. Brody
Keyword(s):  
Cardiovascular Effects ◽  
Renal Nerves ◽  
Renal Nerve ◽  
Conscious Rats ◽  
Arterial Blood ◽  
Regional Hemodynamics ◽  
Renal Nerve Activity ◽  
The Right ◽  
Conscious Animals ◽  
Intact Rats

Bradykinin was infused intravenously and into the right renal artery of conscious rats that were chronically instrumented with catheters and miniaturized pulsed-Doppler flow probes. The effects on regional hemodynamics were compared with those in animals in which the infused kidney was denervated as well as in animals anesthetized with pentobarbital sodium. In intact rats bradykinin (1 microgram/min) caused an immediate increase in mean arterial blood pressure (MAP, 27 +/- 4 mmHg), heart rate (HR, 67 +/- 11 beats/min), mesenteric resistance (MR, 32 +/- 10%), and both right (RRR, 42 +/- 14%) and left renal resistance (LRR 21 +/- 8%). These effects were significantly different from those during intravenous infusion of the same dose of bradykinin (MAP, 6 +/- 3 mmHg; HR, 31 +/- 7 beats/min; MR, -21 +/- 5%; RRR, 8 +/- 4%; LRR, 6 +/- 3%). Pentobarbital greatly attenuated the responses to intrarenal bradykinin. In conscious animals denervation of the infused kidney completely abolished the cardiovascular effects of intrarenal bradykinin. In a separate group of animals, chlorisondamine (7.5 mg/kg iv) completely blocked the increases in MAP and HR during intrarenal bradykinin (1 microgram/min). It is concluded that selective renal administration of bradykinin alters afferent renal nerve activity and that this results in hemodynamic changes consistent with efferent sympathetic activation.

Effects of endothelin on regional hemodynamics in conscious rats

1989 ◽  
Vol 159 (3) ◽  
pp. 303-305 ◽  
Author(s):  
Song Ping Han ◽  
Angelo J. Trapani ◽  
Kam F. Fok ◽  
Thomas C. Westfall ◽  
Mark M. Knuepfer
Keyword(s):  
Conscious Rats ◽  
Regional Hemodynamics
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