Nifedipine in Pheochromocytoma

Favre, L.; Vallotton, Michel B.

doi:10.7326/0003-4819-104-1-125_1

Cited by 17 publications

(7 citation statements)

References 4 publications

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“…Administration of nifedipine, a DHP Ca 2+ channel blocker, to pheochromocytoma patients effectively suppresses the severe rise in blood pressure by decreasing systemic vascular resistance. 4,5) Anesthetic management for surgical removal of pheochromocytomas remains a clinical challenge. 6) However, nicardipine, another DHP Ca 2+ channel blocker, is useful during this surgery to control preoperative and intraoperative hypertension.…”

Section: Channel In Guinea Pig Ventricular Cells By Nitrendipine and mentioning

confidence: 99%

Independent Modulation of L-type Ca2+ Channel in Guinea Pig Ventricular Cells by Nitrendipine and Isoproterenol.

Sonoda

Ochi

2001

Jpn Heart J

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SUMMARY Dihydropyridine (DHP) Ca2+ channel blockers decrease L-type Ca 2+ channel current (I CaL ) by enhancing steady-state inactivation, whereas β-adrenergic stimulation increases I CaL with small changes in the kinetics. We studied the effects of DHP Ca 2+ channel blockers on cardiac I CaL augmented by β-adrenergic stimulation. We recorded I CaL as Ba 2+ currents (I Ba ) from guinea pig ventricular myocytes using the whole-cell patch clamp technique, and compared the effects of nitrendipine (NIT) in the absence and presence of isoproterenol (1 µM, ISO) or forskolin (10 µM, FSK). Maximal I Ba elicited from a holding potential of -80 mV were diminished to 69.4±13.5% (mean and SE, n=5) of control by NIT (100 nM) and the diminished I Ba were increased to 180.3±23.2% of control by ISO in the presence of NIT, which was similar to the enhancement seen in the absence of NIT. NIT shifted the V 1/2 of the I Ba inactivation curve from -34.6±1.9 mV (n=5) to -48.7±1.2 mV, enhancing I Ba decay with shortening T 1/2 at -10 mV from 164.6±24.2 ms (n=7) to 105.4±15.2 ms. ISO elicited a small additional shift in the V 1/2 of I Ba inactivation in the same direction. ISO and FSK each slowed I Ba decay in the absence of NIT, but not in its presence. Thus, β-adrenergic agonists increase and DHP Ca 2+ channel blockers decrease the amplitude of cardiac I CaL independently and the kinetics of I CaL is determined mainly by the latter when these drugs coexist. ( 1,2) They act by depressing L-type Ca 2+ channel currents (I CaL ), which play key roles in excitation-contraction coupling in cardiac and vascular smooth muscle cells (VSM), thereby exhibiting negative inotropic and vasodilatory actions. DHP Ca 2+ channel blockers inhibit I CaL in VSM more readily than in cardiac muscle as a consequence of differences in the resting membrane potentials, which are more

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Section: Channel In Guinea Pig Ventricular Cells By Nitrendipine and mentioning

confidence: 99%

Independent Modulation of L-type Ca2+ Channel in Guinea Pig Ventricular Cells by Nitrendipine and Isoproterenol.

Sonoda

Ochi

2001

Jpn Heart J

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“…Serfas and coworkers [19] demonstrated that another calcium channel blocker, nifedipine, suppressed noradrenaline secretion by a phaeochromocytoma. On the other hand, Lenders and associates [20] and Favre and colleagues [21] reported that nifedipine did not have a direct influence on catecholamine release from the tumour-although it might interfere with the action of catecholamines in patients with phaeochromocytoma. Hypertensive crises during surgery occur when catecholamines are suddenly released from the tumour in response to manipulation.…”

Section: Discussionmentioning

confidence: 98%

Use of Diltiazem to Control Circulatory Fluctuations During Resection of a Phaeochromocytoma

Tokioka

Takahashi

Kōsogabe

et al. 1988

British Journal of Anaesthesia

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This report describes the use of diltiazem to control circulatory fluctuations during anaesthesia in five patients undergoing resection of a phaeochromocytoma. Diltiazem was administered continuously i.v. before anaesthesia and during surgery until the draining vein from the tumour had been ligated. Arterial pressure and systemic vascular resistance decreased in association with the infusion of diltiazem. Heart rate was stable, and there was no ventricular tachyarrhythmia. Arterial pressure was controlled easily during the manipulation of the tumour, and there were no hypotensive episodes after the removal of the tumour.

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“…Recent data suggest use of newer agents like prazosin or doxazosin for the purpose of α-blockade 16. Calcium channel blocker is suited for patients with cardiovascular disease because of its inhibition of catecholamine-induced coronary vasospasm and myocarditis 17 18. Propranolol is commonly used for β-blockade.…”

Section: Discussionmentioning

confidence: 99%

Functional paraganglioma

Balasubramanian¹,

Nellaiappan

2014

BMJ Case Reports

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SUMMARYParaganglioma are tumours arising from neural crest cells of the sympathetic and parasympathetic paraganglia. Functional paraganglioma presents with symptoms of catecholamine excess that includes hypertension, flushing, diaphoresis, etc. Non-functional paraganglioma are usually found incidentally during imaging studies. Early diagnoses of functional paraganglioma are important because their removal is often curative. We present the case of a young man who presented with hypertensive crisis and severe headache, who was later found to have functional paraganglioma. BACKGROUND

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Nifedipine in Pheochromocytoma

Cited by 17 publications

References 4 publications

Independent Modulation of L-type Ca2+ Channel in Guinea Pig Ventricular Cells by Nitrendipine and Isoproterenol.

Independent Modulation of L-type Ca2+ Channel in Guinea Pig Ventricular Cells by Nitrendipine and Isoproterenol.

Use of Diltiazem to Control Circulatory Fluctuations During Resection of a Phaeochromocytoma

Functional paraganglioma

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