Sensitivity of neonatal renal vasculature to epinephrine

Pa, Jose; Slotkoff, LM; Lilienfield, LS; Pl, Calcagno; Eisner, GM

doi:10.1152/ajplegacy.1974.226.4.796

Cited by 41 publications

(9 citation statements)

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“…Previous work (12) has also suggested age-related renal vascular responsiveness in that the renal vasculature of young fetuses appear to be more sensitive to catecholamines during hypoxemia than that of older fetuses. Similarly, increased renal vascular sensitivity to E has been noted in neonatal relative to adult dogs (52).…”

Section: Discussionmentioning

confidence: 72%

Renal Hemodynamic Responses to Hypoxemia during Development: Relationships to Circulating Vasoactive Substances

Weismann

Robillard

1988

Pediatr Res

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ABSTRACT. Chronically catheterized fetal lambs (n = Abbreviations 11, gestational age 111-139 days) and neonatal lambs (n = 20, postnatal age 4-30 days) were studied to explore during development the relationship of renal hemodynamic responses during hypoxemia to plasma epinephrine concentration (E), plasma norepinephrine concentration (NE), plasma arginine vasopressin concentration (AVP), and plasma renin activity (PRA). A low oxygen gas mixture (11.1 f 0.1% 0 2 ) was administered for 30 min to the pregnant ewe or neonatal lamb to induce hypoxemia with maintenance of normal arterial pCOz and pH. Arterial blood pressure was recorded continuously and renal blood flow (RBF) was determined by the radiolabeled microsphere technique. Moderate hypoxemia (p02 16 It 2 torr and 33 f 6 torr in fetus and neonate, respectively) induced increases in E, NE (measured by radioenzymatic assay), and AVP (measured by radioimmunoassay) in both fetus and neonate. PRA (measured by radioimmunoassay) also increased in response to hypoxemia in neonatal lambs. The change in mean arterial pressure with hypoxemia (AMAP) was significant in fetuses (AMAP 8 f 14%, p < 0.05) but not in lambs (AMAP 1 It lo%, p > 0.5). Similarly, the change in renal blood flow with hypoxemia (ARBF) was significant (ARBF -51 f 24%, p < 0.001) in fetuses but not in neonatal lambs (ARBF -9 f 38%, p > 0.1). These results reflected a change in renal vascular resistance with hypoxemia (ARVR) that was significant in fetal lambs (ARVR 169 f 168%, p < 0.01) but not in neonatal lambs (ARVR 51 f 180%, p > 0.2). The relationships of these renal hemodynamic responses to the measured vasoactive substances, and the influence of their interactions to produce these responses, were assessed by response surface regression analysis. The response surface regression model of responses to hypoxemia of E (AE), NE (ANE), AVP (AAVP), and PRA (APRA) to AMAP and ARVR over the entire development period fit the data well (adjusted RZ 0.8427 and 0.8274, respectively). AE was the most predictive of the components for both AMAP and ARVR (F ratio 7.89 and 7.25, respectively). Contour plots of the interaction of AE with postconceptional age and ANE demonstrated considerable age dependence of the relationship of AE and ANE to AMAP and ARVR during development. The results are consistent with the hypothesis that asynchronous maturation of vascular Badrenergic (vasodilatory) and a-adrenergic (vasoconstrictor) effector mechanisms occurs throughout the fetallneonatal period. (Pediatr Res 23: 155-162,1988)

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Section: Discussionmentioning

confidence: 72%

Renal Hemodynamic Responses to Hypoxemia during Development: Relationships to Circulating Vasoactive Substances

Weismann

Robillard

1988

Pediatr Res

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“…However. one may speckate that the use of conscious anikals in our stud; versus anesthetized animals in previous studies (3,4) and species variation may partially explain these differences. It is known that anesthesia may alter RBF (19, 20), depress smooth muscle tone (21), and modify the vascular response to endogenous catecholamines in some vascular beds (22).…”

Section: Discussionmentioning

confidence: 81%

“…4). Jose et al (4) demonstrated that the renal-vascular response to intrarenal'infusion of epinephrine is of greater magnitude in anesthetized newborn dogs than in adult dogs. ~o w e i e r , Buckley et al (3) showed that the renal vasculature of anesthetized swine at birth is less responsive to systemic administration of norepinephrine than older piglets.…”

Section: Discussionmentioning

confidence: 99%

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Effects of Epinephrine on the Renal Vascular Bed of Fetal, Newborn, and Adult Sheep

et al. 1988

Pediatr Res

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ABSTRACT. The renal hemodynamic response to renal artery infusions of epinephrine were compared in conscious and chronically instrumented fetal (125-139 days gestation; term 145 days), newborn (5-13 days postnatal), and nonpregnant adult sheep. Epinephrine produced similar dose related decreases in renal blood flow velocity in all three groups. The mean estimated concentration of epinephrine in renal blood producing a 50% decrease in renal blood flow velocity, ED50, was 0.008 pglml. Epinephrine infusions during renal a-adrenoceptor blockade with phentolamine produced increases in renal blood flow velocity that were of greater magnitude in fetal compared to newborn and adult sheep. The maximal increase in renal blood flow velocity observed were 57 f 11%, 22 & 3%, and 18 + 3% in fetal, newborn, and adult sheep, respectively (p < 0.001). This vasodilation produced by epinephrine during a-adrenoceptor blockade was completely inhibited by ICI 118,551, a P2-adrenoceptor antagonist. Inhibition of renal vascular @-adrenoceptors with propranolol in fetal sheep did not enhance a-adrenoceptor-mediated renal vasoconstriction with epinephrine infusions. Results of the present study demonstrate similar renal vasoconstrictor responses to renal artery infusion of epinephrine in fetal, newborn, and adult sheep. In contrast, the renal vasodilator responses observed with epinephrine infusions during renal a-adrenoceptor blockade were greater in fetal compared to newborn and adult sheep. However, epinephrine-mediated renal vasoconstriction was not enhanced by blockade of Padrenoceptors in fetal sheep. (Pediatr Res 23: 181-186, 1988 than 10-fold higher than in resting adults (1). However, despite these high levels, the phenomenon of birth is associated with an increase in RBF and glomerular filtration (2) suggesting that the developing kidney may respond differently to catecholamine stimulation than the adult.In this respect, Buckley et al. (3) found that the renal vasculature of anesthetized newborn piglets is less sensitive to aadrenoceptor stimulation than older swine. However, Jose et al. (4) have shown that anesthetized puppies were more sensitive to intrarenal epinephrine than adults and had increased renal aadrenoceptor affinity and density compared to adult dogs (5).To further investigate the functional role of circulating catecholamines in modulating renal hemodynamics during devel-A opment, the present study was designed to specifically examine the developmental response of the renal vascular bed to direct intrarenal infusions of epinephrine, using conscious and chronically instrumented fetal, newborn, and nonpregnant adult sheep. METHODSAnimal preparation and surgical procedures. Fetuses of 14 pregnant sheep of Dorset and Suffolk mixed breeding were studied between 125 and 139 days gestation (term 145 days). Gestational ages were based on the induced ovulation technique as previously described (6).Ewes were fasted for 48 h before surgery. General anesthesia of the ewe and fetal surgery were performed as previously descri...

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“…If this observation applies to nerve endings as well, then one would anticipate that increased adrenergic activity in a nervous pathway would diminish substance P levels throughout the tract. Because we have found increased adrenergic activity in the young (13,16), the neonatal period may be characterized by a decreased amount of substance P and consequently, lower kallikrein activity. Therefore, in the newborn, decreased kallikrein/kinin activity could be intimately linked to a maturational process involving the neural control of diverse renal functions.…”

Section: Discussionmentioning

confidence: 66%

Enhancement of Sodium Excretion by Substance P during Saline Loading in the Canine Puppy

et al. 1983

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Sensitivity of neonatal renal vasculature to epinephrine

Cited by 41 publications

References 0 publications

Renal Hemodynamic Responses to Hypoxemia during Development: Relationships to Circulating Vasoactive Substances

Renal Hemodynamic Responses to Hypoxemia during Development: Relationships to Circulating Vasoactive Substances

Effects of Epinephrine on the Renal Vascular Bed of Fetal, Newborn, and Adult Sheep

Enhancement of Sodium Excretion by Substance P during Saline Loading in the Canine Puppy

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