Organic Nitrates: Analytical Techniques

Bogaert, Marc G.

doi:10.1007/978-3-642-66024-5_3

Cited by 2 publications

(1 citation statement)

References 55 publications

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“…Despite the wide-spread, daily administration of these compounds to patients with coronary heart disease, as well as extensive studies using experimental animals, the mechanisms involved in their action remain poorly understood. Brunton (1867) initially investigated the effects of amyl nitrate in the relief of angina pectoris as related to its hypotensive action (Voegtlin & Macht, 1913;Bogaert, 1972) and it is widely believed that the effects 0007-1188/80/100197-08 $01.00 of nitrates are derived primarily from their peripheral actions and not necessarily due to direct effects on the coronary circulation. Recently, in the light of data demonstrating that nitrates affect the regional distribution of coronary flow, the coronary bed has again been advocated as an important site for the action of nitroglycerine (NG) (review of Vatner & Heyndricks, 1975).…”

Section: Introductionmentioning

confidence: 99%

Actions of Nitroglycerine on the Membrane and Mechanical Properties of Smooth Muscles of the Coronary Artery of the Pig

Ito

Kitamura

Kuriyama

1980

British J Pharmacology

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Effects of nitroglycerine (NG) on the membrane and contractile properties of the smooth muscle cell of the isolated coronary artery of the pig were observed. NG, up to a concentration of 10−5 m, modified neither the membrane potential nor the membrane resistance. Increased concentrations of NG (> 2.8 × 10−5 m) hyperpolarized the membrane, reduced the membrane resistance and enhanced the rectifying property of the membrane measured by depolarization pulses. These phenomena observed with a high concentration of NG are the result of an increase in the K‐conductance of the membrane. NG (2.8 × 10−5 m) did not modify the membrane potential displaced by various concentrations of excess [K]o. In low [K]o, NG (2.8 × 10−5 m) hyperpolarized the membrane to a greater extent than that observed in Krebs solution. The effects of NG (10−6 to 2.8 × 10−5 m) on the membrane potential were not modified by simultaneous application of 2 × 10−6 m acetylcholine (ACh). NG (2.8 × 10−6 m) consistently raised the mechanical threshold required for tension development and suppressed the amplitude of the contraction evoked by excess [K]o, ACh or electrical depolarization of the membrane. The dose‐response curve shifted to the right in the presence of NG noncompetitively in all the conditions employed to develop the tension. When the tissue was immersed in Ca‐free (EGTA) solution, ACh (5 × 10−6 m) evoked a contraction even after the tissue had lost the ability to contract to repetitive applications of 118 mm [K]o in Ca‐free (EGTA) solution. However, the tissue finally failed to contract to repetitively applied ACh. At this stage, 2.5 mm [Ca]o evoked a small contraction, after which the response was briefly restored to 5 × 10−6 m ACh. This transient response to ACh was reduced by NG (5.6 × 10−6 m) when NG was added either simultaneously with ACh or with the previous Ca application. However, the inhibition was greater in the former than the latter case. Cysteine (1 to 2 mm), without modifying the membrane potential or membrane resistance, partly restored the contraction evoked by excess [K]o or ACh which had been reduced by NG. The mechanism of action of NG on the smooth muscle cell of the coronary artery of the pig is postulated to be due to a nonselective suppression of the Ca‐mobilization from the store site with no noticeable change in the membrane properties.

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Section: Introductionmentioning

confidence: 99%

Actions of Nitroglycerine on the Membrane and Mechanical Properties of Smooth Muscles of the Coronary Artery of the Pig

Ito

Kitamura

Kuriyama

1980

British J Pharmacology

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Measurement of plasma concentrations of isosorbide dinitrate

Doyle¹,

Chasseaud²,

Taylor³

1980

Biopharm & Drug Disp

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Concentrations of the vasodilator isosorbide dinitrate (ISDN) in human plasma can be measured with good sensitivity (about 0.2--0.5 ng ml-1) using electron-capture gas chromatography after a one-stage extraction. The mean recovery of ISDN from plasma was 83 per cent +/- 9 standard deviation (S.D.). The precision of the method for the measurement of ISDN in plasma ranged from +/- 14 per cent at 1 ng ml-1 to +/- 7 per cent at 5 ng ml-1 to +/- 4 per cent at 50 ng ml-1. The 95 per cent confidence limits of the least-squares regression calibration line forced through the origin were +/- 100 percent at 1 ng ml-1, +/- 11 per cent at 10 ng ml-1, and +/- 8 per cent at 30 ng ml-1. The method has been used to assay many samples withdrawn after doses of drug at therapeutic levels to normal subjects.

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Organic Nitrates: Analytical Techniques

Cited by 2 publications

References 55 publications

Actions of Nitroglycerine on the Membrane and Mechanical Properties of Smooth Muscles of the Coronary Artery of the Pig

Actions of Nitroglycerine on the Membrane and Mechanical Properties of Smooth Muscles of the Coronary Artery of the Pig

Measurement of plasma concentrations of isosorbide dinitrate

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