Neonatal capsaicin treatment impairs vasopressin‐mediated blood pressure recovery following acute hypotension

Bennett, T.; Gardiner, Sheila M.

doi:10.1111/j.1476-5381.1984.tb10084.x

Cited by 8 publications

(8 citation statements)

References 15 publications

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“…Although we did not make direct assessments of the extent of capsaicin-induced lesions in the present study, the protocol we followed has been found to cause a selective and permanent destruction of about 90% of the peripheral, unmyelinated afferent fibres (Nagy et al, 1981). Furthermore, the impaired blood pressure recovery in capsaicin-treated rats which we observed following administration ofpentolinium and captopril is consistent with our previous findings (Bennett & Gardiner, 1984) and assured us that the capsaicin-treated animals used in this study had been affected to a similar extent as those used previously. The present results obtained in conscious animals are similar to those obtained under anaesthesia (Bond et al, 1982;Lorez et al, 1983) which showed that adult rats, treated neonatally with capsaicin, had normal, resting arterial blood pressures.…”

Section: Discussionsupporting

confidence: 91%

“…Furthermore, the impaired blood pressure recovery in capsaicin-treated rats which we observed following administration ofpentolinium and captopril is consistent with our previous findings (Bennett & Gardiner, 1984) and assured us that the capsaicin-treated animals used in this study had been affected to a similar extent as those used previously.…”

Section: Discussionsupporting

confidence: 80%

“…We have recently demonstrated impaired vasopressinmediated blood pressure recovery following acute hypotension in water-deprived, adult rats that had been treated neonatally with a dose of capsaicin which selectively destroys unmyelinated afferent nerve fibres (Bennett & Gardiner, 1984). This we interpreted as being due to capsaicin-induced diminution of the reflex release of vasopressin, consistent with the suggestion that unmyelinated nerve fibres are involved in the afferent pathways mediating the non-osmotic release of vasopressin (Thoren, 1979); but the possibility remained that the capsaicin-treated animals had a normal reflex release of vasopressin and were less sensitive to the cardiovascular actions of the hormone.…”

Section: Introductionmentioning

confidence: 99%

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Pressor sensitivity to exogenous vasopressin in conscious, adult rats treated neonatally with capsaicin

Bennett

Gardiner

1985

British J Pharmacology

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1 Pressor responses to exogenous arginine vasopressin were assessed in adult rats that had been treated neonatally with capsaicin or its vehicle. Measurements were made under control conditions, after inhibition of baroreflexes (with pentolinium), and after inhibition of baroreflexes (with pentolinium) and the production of angiotensin II (with captopril). 2 Resting arterial blood pressures and pressor sensitivities to exogenous arginine vasopressin were similar in capsaicin-treated and vehicle-injected rats. 3 Sixty minutes after the administration of pentolinium, systolic and diastolic blood pressures were reduced in both groups of rats and the pressor responses to arginine vasopressin were similarly and significantly enhanced. 4 In both groups of rats 60 min after administration of pentolinium and captopril, systolic and diastolic blood pressures were lower than in the presence of pentolinium alone, but pressor responses were not different from those seen in control conditions. 5 The possibility that the present results are explicable in terms of baroreflexes, the renin-angiotensin system and endogenous vasopressin interacting to influence the pressor sensitivity to exogenous vasopressin is discussed. From the present findings, it seems that our previous observation ofimpaired, vasopressin-mediated blood pressure recovery following acute hypotension in capsaicin-treated rats cannot be attributed to a reduced pressor sensitivity to the hormone.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionsupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

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Pressor sensitivity to exogenous vasopressin in conscious, adult rats treated neonatally with capsaicin

Bennett

Gardiner

1985

British J Pharmacology

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“…Unmyelinated afferent fibres may be involved in the reflex release of vasopressin in response to non-osmotic stimuli (Thoren, 1979), and consistent with this, we recently showed impaired vasopressin-mediated blood pressure recovery following acute hypotension in waterdeprived, adult Wistar rats which had received capsaicin neonatally (Bennett & Gardiner, 1984). In our previous study, we commented on the fact that fluid balance (as judged by body weight loss) in capsaicintreated animals was not different from that of the control animals during water deprivation.…”

Section: Introductionmentioning

confidence: 74%

The influence of neonatal treatment with capsaicin on the control of blood pressure in adult rats in water‐replete and water‐deprived states

Bennett

Gardiner

1985

British J Pharmacology

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1 Arterial blood pressures and heart rates were measured in water-replete and in water-deprived (48 h) conscious, adult rats that had received capsaicin (50mg kg') or its vehicle neonatally. 2 Resting arterial blood pressures and heart rates in capsaicin-treated rats were not different from the controls in either the water-replete or the water-deprived state.3 Inhibition of the vascular actions of vasopressin (with l-p-mercapto,-P,-cyclopentamethylenepropionic acid, 8-D-arginine vasopressin, (d(CH2)5DAVP)) had no significant effect on blood pressures in the water-replete animals but caused a significant hypotension in water-deprived rats; the magnitude of the hypotension was the same irrespective of whether the animals had received capsaicin or its vehicle. 4 During angiotensin converting enzyme inhibition (with captopril) and ganglion blockade (with pentolinium), the vasopressin-mediated blood pressure recovery was more gradual in the capsaicintreated animals than in the controls, but after 60 min blood pressures were similar in all groups. Collectively the results indicate that although the full development of vasopressin-dependent mechanisms following acute hypotension takes longer when a large proportion of unmyelinated afferent fibres have been destroyed by neonatal treatment with capsaicin, 48 h of water deprivation results in a normal involvement of vasopressin-dependent mechanisms in the maintenance of blood pressure.

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“…Angiotensin II is an endogenous vasocon strictor peptide which is important in main taining the blood pressure in the fetus and probably in the newborn, as well [1][2][3][4][5][6][7]. While it is a pulmonary vasoconstrictor in adult animals, limited evidence suggests that it is less potent in this regard in the subtracting mean left atrial pressure from mean pul monary arterial pressure and dividing by the mean pulmonary blood flow.…”

Section: Introductionmentioning

confidence: 99%

Hemodynamic Responses to Angiotensin II in the Newborn Lamb

Goetzman¹,

Bennett²

1991

Dev Pharmacol Ther

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Angiotensin II is known to increase both pulmonary and systemic arteriolar tone in adult animals. Its influence on these vascular beds shortly after birth is less well understood. Therefore, we studied the effects of infusions of angiotensin II (0.1 μg/kg/min) on pulmonary and systemic hemodynamics in 13 anesthesized newborn lambs. Systemic vascular resistance increased significantly from a mean of 0.079 ± 0.03 to 0.094 ± 0.04 mm Hg/ml/min during angiotensin II infusion while the mean pulmonary vascular resistance was unchanged at 0.024 ± 0.01 mm Hg/ml/min. Interestingly, cardiac output increased significantly by 18.9% during angiotensin II infusion. During hypoxemia produced by ventilating with 10-12% oxygen, the responses to angiotensin II infusion were similar to those obtained during normoxia. The absence of an effect on pulmonary vascular resistance and the increase in cardiac output were not predicted based on results reported for older animals. The mechanisms responsible for these age-related differences are unknown. Our findings have implications regarding the potential clinical use of angiotensin II as a modulator of blood pressure in the hypotensive newborn.

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Neonatal capsaicin treatment impairs vasopressin‐mediated blood pressure recovery following acute hypotension

Cited by 8 publications

References 15 publications

Pressor sensitivity to exogenous vasopressin in conscious, adult rats treated neonatally with capsaicin

Pressor sensitivity to exogenous vasopressin in conscious, adult rats treated neonatally with capsaicin

The influence of neonatal treatment with capsaicin on the control of blood pressure in adult rats in water‐replete and water‐deprived states

Hemodynamic Responses to Angiotensin II in the Newborn Lamb

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