Carotid arterial control of vasopressin secretion in sheep

1984 ◽  
Vol 247 (3) ◽  
pp. R589-R594 ◽  
Author(s):  
C. E. Wood ◽  
L. C. Keil ◽  
A. M. Rudolph

The purpose of this study was to test the role of carotid arterial mechanoreceptors in the control of vasopressin secretion in conscious 6- to 7-wk-old lambs. Bilateral carotid occlusion decreased lingual arterial pressure and stimulated reflex increases in heart rate and femoral arterial blood pressure but did not significantly alter plasma concentrations of vasopressin. Acute vagosympathetic blockade, produced by injection of 2% lidocaine onto the vagosympathetic trunks, did not significantly alter heart rate or blood pressure but did stimulate a slow increase in plasma vasopressin concentration, suggesting that afferent vagal fibers tonically inhibit vasopressin secretion. Bilateral carotid occlusion after vagosympathetic blockade stimulated a brisk increase in plasma vasopressin that was larger than the response to vagosympathetic blockade alone. These results suggest that vasopressin secretion in lambs is partially controlled by arterial mechanoreceptors in the carotid sinus and by extracarotid receptors with vagosympathetic afferent fibers.

1987 ◽  
Vol 62 (3) ◽  
pp. 1186-1191 ◽  
Author(s):  
J. W. Kozelka ◽  
G. W. Christy ◽  
R. D. Wurster

The ascending spinal pathways mediating somatocardiovascular reflexes during exercise were studied in unanesthetized dogs by placing lesions in the lumbar spinal cord. After training to run on a treadmill with hindlimbs only, 20 dogs were anesthetized and instrumented using sterile surgical techniques. To chronically record heart rate and arterial blood pressure, the aorta was cannulated via the omocervical artery. To test the intactness of descending spinal sympathetic pathways, reflex pressor responses to baroreceptor hypotension were produced by bilateral carotid arterial occlusion using pneumatic vessel occluders placed around the common carotid arteries. To generate transient ischemic exercise (120 s), a pneumatic occluder was placed around the left iliac artery. Eight to 10 days after instrumentation, blood pressure and heart rate were monitored at rest and during hindlimb running with and without simultaneous iliac arterial occlusion. The modest pressor response and tachycardia elicited by hindlimb exercise were markedly augmented by simultaneous hindlimb ischemia (i.e., iliac arterial occlusion). Lesion placement in the dorsolateral sulcus area and the dorsolateral funiculus at L2 significantly reduced the blood pressure and heart rate responses to simultaneous exercise occlusion. The cardiovascular responses to nonischemic exercise and bilateral carotid arterial occlusion were not altered by such spinal sections. It is concluded that in the dog the ascending spinal pathways mediating cardiovascular responses to ischemic exercise are located in the lateral funiculus, including the dorsolateral sulcus area and dorsolateral funiculus.


1991 ◽  
Vol 261 (2) ◽  
pp. R420-R426
Author(s):  
M. Inoue ◽  
J. T. Crofton ◽  
L. Share

We have examined in conscious rats the interaction between centrally acting prostanoids and acetylcholine in the stimulation of vasopressin secretion. The intracerebroventricular (icv) administration of carbachol (25 ng) resulted in marked transient increases in the plasma vasopressin concentration and mean arterial blood pressure and a transient reduction in heart rate. Central cyclooxygenase blockade by pretreatment icv with either meclofenamate (100 micrograms) or indomethacin (100 micrograms) virtually completely blocked these responses. Prostaglandin (PG) D2 (20 micrograms icv) caused transient increases in the plasma vasopressin concentration (much smaller than after carbachol) and heart rate, whereas mean arterial blood pressure rose gradually during the 15-min course of the experiment. Pretreatment with the muscarinic antagonist atropine (10 micrograms icv) decreased the peak vasopressin response to icv PGD2 by approximately one-third but had no effect on the cardiovascular responses. We conclude that the stimulation of vasopressin release by centrally acting acetylcholine is dependent on increased prostanoid biosynthesis. On the other hand, stimulation of vasopressin release by icv PGD2 is partially dependent on activation of a cholinergic pathway.


2008 ◽  
Vol 76 (1) ◽  
pp. 15-19 ◽  
Author(s):  
Kerstin Olsson ◽  
Madeleine Högberg

Goats are often kept on small farms where they suckle kids and are hand milked for human consumption. Our first objective was to investigate whether vasopressin secretion increases together with oxytocin during hand milking and suckling in seven goats 6–8 weeks after parturition. Four goats suckled and three were hand milked on the first day and the treatments were reversed on the next day. Blood samples were taken via a semi-permanent catheter. Plasma concentrations of vasopressin and oxytocin increased during suckling, but not during hand milking. Plasma cortisol concentration was elevated for 10 min after both treatments. These results initiated a second series in which the objectives were to measure vasopressin and oxytocin concentrations during hand milking in a larger number of goats and to investigate whether the rise in cortisol concentration was due to the experimental conditions or to milking, by adding a no-milking treatment. Nine goats in lactation weeks 4–10 were studied. Heart rate and arterial blood pressure were registered in eight of the goats. Oxytocin concentration did not change during hand milking and the vasopressin concentration was below the detection limit. Heart rate and blood pressure were elevated during milking and for about 10 min thereafter. Cortisol concentration increased after milking, as above. None of the variables changed in the no-milking treatment. This suggests that the rise in cortisol concentration was due to milk excretion and was not a stress reaction. In conclusion, suckling increased plasma concentrations of vasopressin and oxytocin, but hand milking did not. In a mixed system, presence of the kids may be necessary to stimulate release of the peptides and thereby contraction of the myoepithelial cells. However, milk stored in the udder cisterns can be obtained by hand milking without presence of oxytocin or vasopressin.


1986 ◽  
Vol 251 (1) ◽  
pp. R126-R136 ◽  
Author(s):  
C. A. Combs ◽  
O. A. Smith ◽  
C. A. Astley ◽  
E. O. Feigl

Bilateral carotid occlusion was performed in seven baboons during dynamic leg exercise, static arm exercise, feeding, rest, and sleep. The baroreceptor reflex effects on blood pressure, heart rate and interval, renal blood flow, and terminal aortic blood flow were determined during each behavior. The carotid sinus baroreflex increase in blood pressure and heart rate was greatest during sleep and least during exercise. The hindlimb and renal vasomotor responses followed different patterns. The baroreceptor reflex sensitivity for renal vasoconstriction was greatest during rest and least during sleep. The reflex sensitivity in the hindlimb was unaltered by behavior. Thus behavior modifies baroreceptor reflex responses in the heart and peripheral circulation in different patterns.


1990 ◽  
Vol 258 (4) ◽  
pp. R930-R938 ◽  
Author(s):  
R. E. Shade ◽  
V. S. Bishop ◽  
J. R. Haywood ◽  
C. K. Hamm

The purpose of this study was to describe the hormonal and blood pressure responses to partial (carotid sinus) and complete (carotid sinus + aortic arch) baroreceptor denervation in baboons. Experiments were performed in eight adult male baboons maintained on a tether system for the continuous measurement of mean arterial blood pressure (MAP) and heart rate (HR). Bilateral carotid sinus denervation (CSD) immediately increased MAP from 83 +/- 2.2 to 124 +/- 7.3 mmHg. MAP gradually decreased over the next 14 days to intact levels. There were also transient decreases in HR variability and increases in blood pressure variability after CSD. Subsequent denervation of the aortic arch to produce sinoaortic denervation (SAD) resulted in another abrupt large increase in MAP followed by a small but significant increase in MAP of 11 mmHg that was maintained for up to 4 wk after SAD. The short-term variability of HR and blood pressure was chronically decreased and increased, respectively, after SAD. Plasma renin activity, vasopressin, and epinephrine were not changed from intact levels either after CSD or SAD. Plasma norepinephrine was only transiently increased by CSD and chronically elevated by 72% over intact levels after SAD. Thus CSD in the baboon does not produce a sustained increase in MAP. SAD chronically increases MAP and is associated with evidence for an increased sympathetic tone. There is no indication that either increased renin secretion or vasopressin secretion contributes to the chronic cardiovascular effects of SAD in baboons.


1991 ◽  
Vol 260 (5) ◽  
pp. E780-E786 ◽  
Author(s):  
J. D. Stone ◽  
J. T. Crofton ◽  
L. Share

Hemorrhage-induced changes in the plasma vasopressin concentration and mean arterial blood pressure (MABP) were studied in conscious rats of both sexes with and without central alpha 1-adrenoreceptor blockade. Rats were subjected to two sequential hemorrhages (H1 and H2), each 0.8% of body weight after an intracerebroventricular injection of the alpha 1-adrenoreceptor antagonist corynanthine or of vehicle. H1 stimulated vasopressin secretion more in proestrous females than in males; there were no significant sex-related differences in responses to H2. Corynanthine pretreatment attenuated the vasopressin response to H2 in males, potentiated this response in proestrous females, but had no effect in estrous females. MABP decreased after H1 in all female groups and in corynanthine-pretreated males. After H2, all groups were hypotensive to the same extent. These data indicate that central alpha 1-adrenoreceptor-mediated pathways participate in vasopressin and blood pressure responses to hemorrhage, but their role is complex and is dependent on gender and on the phase of the estrous cycle.


1988 ◽  
Vol 255 (3) ◽  
pp. H514-H524
Author(s):  
J. M. Dabney ◽  
M. J. Buehn ◽  
D. E. Dobbins

Regulation of lymphatics by sympathetic nerves or hormones seems probable. To elucidate this, we perfused a lymphatic vessel in the paw of the anesthetized dog while measuring lymphatic perfusion pressure. We studied the effects of norepinephrine, epinephrine, hemorrhage, and carotid occlusion on lymphatic pressure. Blood was pumped to the forelimb via the brachial artery. Cannulas were placed to measure systemic, central venous, and forelimb vascular pressures. Catecholamines, whether added to the lymphatic perfusate or infused into the forelimb arterial blood, and bilateral carotid occlusion significantly increased lymphatic perfusion pressure. Perfusion of prenodal lymphatics disconnected from downstream vessels and nodes indicated that this increase occurred primarily in prenodal lymph vessels. Hemorrhagic hypotension to 55 mmHg did not affect lymphatic pressure but reduction to 35 mmHg did. The increase in lymphatic pressure produced by epinephrine and norepinephrine was blocked by phentolamine. Increased lymphatic perfusion pressure subsequent to exogenous catecholamines, severe hemorrhagic hypotension, or bilateral carotid occlusion supports the possibility that lymphatic function is modulated by adrenergic mechanisms in physiological and/or pathophysiological states.


1989 ◽  
Vol 66 (4) ◽  
pp. 1736-1743 ◽  
Author(s):  
L. B. Rowell ◽  
D. G. Johnson ◽  
P. B. Chase ◽  
K. A. Comess ◽  
D. R. Seals

The experimental objective was to determine whether moderate to severe hypoxemia increases skeletal muscle sympathetic nervous activity (MSNA) in resting humans without increasing venous plasma concentrations of norepinephrine (NE) and epinephrine (E). In nine healthy subjects (20–34 yr), we measured MSNA (peroneal nerve), venous plasma levels of NE and E, arterial blood pressure, heart rate, and end-tidal O2 and CO2 before (control) and during breathing of 1) 12% O2 for 20 min, 2) 10% O2 for 20 min, and 3) 8% O2 for 10 min--in random order. MSNA increased above control in five, six, and all nine subjects during 12, 10, and 8% O2, respectively (P less than 0.01), but only after delays of 12 (12% O2) and 4 min (8 and 10% O2). MSNA (total activity) rose 83 +/- 20, 260 +/- 146, and 298 +/- 109% (SE) above control by the final minute of breathing 12, 10, and 8% O2, respectively. NE did not rise above control at any level of hypoxemia; E rose slightly (P less than 0.05) at one time only with both 10 and 8% O2. Individual changes in MSNA during hypoxemia were unrelated to elevations in heart rate or decrements in blood pressure and end-tidal CO2--neither of which always fell. We conclude that in contrast to some other sympathoexcitatory stimuli such as exercise or cold stress, moderate to severe hypoxemia increases leg MSNA without raising plasma NE in resting humans.


1956 ◽  
Vol 185 (3) ◽  
pp. 483-486 ◽  
Author(s):  
Shirley H. Brind ◽  
Joseph R. Bianchine ◽  
Matthew N. Levy

Changes in cardiac output, mean arterial blood pressure, hematocrit ratio, and arterial and venous oxygen content resulting from bilateral carotid occlusion were investigated. Cardiac output exhibited no significant alteration during endosinusal hypotension, and the systemic hypertension engendered was attributed to an increase in vasomotor tone. Arterial and venous oxygen content, as well as hematocrit ratio, increased significantly during the period of carotid occlusion. This increase was ascribed to splenic contraction evoked by carotid occlusion, since no comparable augmentation was observed when the splenic circulation was temporarily interrupted.


2018 ◽  
Vol 32 (S1) ◽  
Author(s):  
Fernanda Brognara ◽  
Jaci Airton Castania ◽  
Daniel Penteado Martins Dias ◽  
Alexandre Kanashiro ◽  
Luis Ulloa ◽  
...  

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