Neurogenic and mechanical control of canine uterine vascular resistance

Mj, Ryan; Clark, K; Brody, Matthew J.

doi:10.1152/ajplegacy.1974.227.3.547

Cited by 35 publications

(20 citation statements)

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“…The anatomical spiraling of the uterine arteries as they traverse the myometrium is thought to prevent constriction of the vessels as the myometrium contracts. The change in uterine vascular resistance produced by uterine nerve stimulation can be separated from the effect of compression by myometrial contraction (14).…”

Section: Discussionmentioning

confidence: 99%

“…However, the human uterus contains a rich autonomic innervation (16) and pharmacological studies have demonstrated the presence of both alpha and beta receptors. Isoproterenol increases UPBF in the pregnant rabbit (5), and stimulation of the uterine nerve in the pregnant dog causes uterine vasodilatation (14). Thus, the uterine vasculature does not lack the neurogenic capacity to vary vascular resistance.…”

Section: Discussionmentioning

confidence: 99%

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The effect of changes in perfusion pressure on uteroplacental blood flow in the pregnant rabbit.

Venuto¹,

Cox²,

Stein³

et al. 1976

J. Clin. Invest.

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A B S T R A C T The effect of perfusion pressure on uteroplacental blood flow was determined in pregnant rabbits utilizing the radioactive microsphere method.Control mean arterial pressure, 93 mm Hg±2.6 SEM, was raised by carotid ligation to 109±4.1 mm Hg and then reduced with antihypertensive drugs to 74+1.3 mm Hg. Over this range of pressure there was no significant change in cardiac output, 605+36, 523+37, and 540±39 ml/min; or uteroplacental blood flow, 30+3.2, 27±5.2, and 29±4.5 ml/min, respectively. When prostaglandin synthesis was inhibited with either indomethacin or meclofenamate (2 mg/kg), uterine vascular resistance was higher but maintenance of uteroplacental flow occurred over a perfusion pressure of 89±6.7-115 +9.3 mm Hg. With more severe hypotension induced with trimethaphan, control arterial pressure fell from 92±2.4 to 39+0.9 mm Hg, cardiac output fell from 514 +17 to 407+22 ml/min (P < 0.025) and uteroplacental blood flow fell from 6.1±0.9 to 2.5±0.9% of cardiac output (P<0.05), which represented an absolute fall from 32.4±5 to 10.6±3 ml/min (P <0.025). There was no significant change in renal blood flow expressed as percentage of cardiac output, 14.9+2 and 13±1.5%, or in absolute flow, 75+77 and 54+7 ml/min with trimethaphan-induced hypotension.These studies indicate that uteroplacental blood flow is maintained relatively constant over a range of perfusion pressure of 60-140 mm Hg in both normal and prostaglandin-inhibited pregnant rabbits. However, with reduction in pressure to 36-42 mm Hg, uteroplacental blood flow falls, expressed as a percentage of cardiac output and in absolute flow.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

The effect of changes in perfusion pressure on uteroplacental blood flow in the pregnant rabbit.

Venuto¹,

Cox²,

Stein³

et al. 1976

J. Clin. Invest.

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show abstract

“…There is also a fall in the uterine content of noradrenaline. These declines have been observed in the guinea-pig (Sjöberg, 1968), rabbit (Rosengren & Sjöberg, 1968), man (Nakanishi, McLean, Wood & Burnstock, 1968) and dog (Ryan, Clark & Brody, 1974) and Bell ( 1972) has suggested that they constitute a protective mechanism against feto-placental ischaemia during generalized maternal sympathetic activation.…”

Section: Introductionmentioning

confidence: 92%

Observations on the loss of catecholamine fluorescence from intrauterine adrenergic nerves during pregnancy in the guinea-pig

Bell¹,

Malcolm²

1978

Reproduction

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Summary. During unilateral pregnancy in the guinea-pig there is loss of formaldehyde\x=req-\ induced fluorescence from the adrenergic nerves supplying the uterus and its vasculature. This loss occurs initially near the site of implantation at about Day 20 of gestation and spreads progressively. Implantation of wax pellets containing progesterone into the uterine lumen or the gastrocnemius muscle of virgin guinea-pigs for 7 days produced loss of fluorescence from all local adrenergic nerves. No diminution of fluorescence was seen when pellets containing oestradiol were substituted. Chronic denervation studies showed that the adrenergic axons supplying the uterus and its arteries originated from both the ovarian artery and the pelvic region. Our results suggest that loss of adrenergic fluorescence within the uterus during pregnancy is due to an effect of placental progesterone which is localized to the uterus because the high concentration of progesterone necessary to cause fluorescence loss is not attained in the systemic circulation.

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“…Norepinephrine was extracted and assayed from vessels with a modification 12 of the method described by Anton and Sayre. 13 We also examined the vessels with a modification 14 of the histofluorescence technique of Falck-Hillarp.…”

Section: Effect Of Hypotension Hypertension and Hypocapnia After Chmentioning

confidence: 99%

Total and regional cerebral blood flow during hypotension, hypertension, and hypocapnia. Effect of sympathetic denervation in dogs.

Mueller¹,

Heistad²,

Marcus³

1977

Circulation Research

108

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CEREBRAL blood vessels are innervated by adrenergic nerve fibers from the cervical sympathetic chain.1 -2 The main source of this sympathetic innervation is the superior cervical ganglion, 3 with a small contribution in dogs from the stellate ganglion. 4 Although cerebral vessels are densely innervated, the significance of these sympathetic nerves in regulation of cerebral blood flow (CBF) is controversial.Several previous studies have evaluated the functional significance of sympathetic nerves by examining regulation of cerebral flow after acute 5 -6 or chronic 7 -8 sympathetic denervation. Acute cervical sympathectomy has been reported to increase CBF over a wide range of arterial pressure, 5 particularly at normal and elevated levels of pressure. In contrast, a recent report suggests that acute cervical sympathectomy does not increase CBF at normal levels of arterial pressure but does increase flow during hypotension." Chronic sympathetic denervation has been reported to have no effect on CBF,' 1 " 8 but effectiveness of denervation was not confirmed by demonstrating depletion of vascular catecholamines. It seems reasonable to suggest that previous studies have not resolved the question of the effect of sympathetic denervation on control of CBF. Furthermore, the methods that were used to measure CBF have not allowed examination of the effect of denervation on distribution of blood flow within the brain.In this study, we have examined effects of acute and chronic unilateral sympathetic denervation on total and regional CBF. Labeled microspheres were used to measure CBF. 9 The microsphere technique circumvents the problems created by the presence of multiple vessels to and from the brain and allows measurement of both total and regional CBF. The measurement of regional CBF allowed us to compare distribution of CBF simultaneously in the hemisphere ipsilateral to the sympathetic denervation and in the contralateral "control" hemisphere. We postulated that unilateral acute sympathetic denervation or depletion of cerebral vascular catecholamines might increase CBF to the ipsilateral hemisphere or redistribute CBF in the ipsilateral hemibrain.Several studies were performed to test this hypothesis. Total and regional CBF were measured during control

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Neurogenic and mechanical control of canine uterine vascular resistance

Cited by 35 publications

References 0 publications

The effect of changes in perfusion pressure on uteroplacental blood flow in the pregnant rabbit.

The effect of changes in perfusion pressure on uteroplacental blood flow in the pregnant rabbit.

Observations on the loss of catecholamine fluorescence from intrauterine adrenergic nerves during pregnancy in the guinea-pig

Total and regional cerebral blood flow during hypotension, hypertension, and hypocapnia. Effect of sympathetic denervation in dogs.

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