<b>Comparative Effects of Hydralazine, Sodium Nitrite and Acetylcholine on Resistance and Capacitance Blood Vessels and Capillary Filtration in Skeletal Muscle in the Cat</b>

Åblad, Bengt; Mellander, Stefan

doi:10.1111/j.1748-1716.1963.tb02654.x

Cited by 71 publications

(34 citation statements)

References 10 publications

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“…The direct effects of the drug on resistance and capacitance vessels have not previously been studied in man, but our findings are in general agreement with studies of sodium nitrite in both animals and man (Ablad & Mellander, 1963;Ablad & Johnsson, 1963).…”

Section: Local Effects Ofdilators In Arteries and Veinssupporting

confidence: 82%

Comparison of effects of tolmesoxide (RX71107), diazoxide, hydrallazine, prazosin, glyceryl trinitrate and sodium nitroprusside on forearm arteries and dorsal hand veins of man.

Collier¹,

Lorgé²,

Robinson³

1978

Brit J Clinical Pharma

122

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I Dilator drugs used in treatment of hypertension and angina pectoris vary greatly in their clinical effects. The action of selected drugs of this group on the human forearm arterial bed and dorsal hand veins has been studied in an attempt to account for these differences. 2 Arterial responses were studied by infusing the drug into the brachial artery and measuring changes in forearm blood flow by plethysmography. Venous responses were studied by local infusion of the drug into a dorsal hand vein preconstricted by infusion of noradrenaline or other constrictor agent and measuring changes in vein size at a standard congesting pressure. 3 Tolmesoxide (RX7 1107), diazoxide, prazosin, glyceryl trinitrate and sodium nitroprusside produced dose dependent increases in forearm flow which had a rapid onset and waned quickly when the drug was discontinued. The response to hydrallazine was delayed and reached a maximum about 30 min after completion of short infusions. 4 Tolmesoxide, diazoxide, prazosin, glyceryl trinitrate and sodium nitroprusside all produced dilatation of the constricted hand vein. Hydrallazine had a weak dilator effect in some subjects but the responses were inconsistent. 5 Tolmesoxide was approximately equipotent in dilating arteries and veins, and diazoxide behaved similarly. Prazosin, glyceryl trinitrate and sodium nitroprusside were relatively more effective in the veins than the arteries. Hydrallazine was much more effective in arteries than veins. 6 The relative effectiveness of these drugs on peripheral arteries and veins can be correlated with their action on the circulation as a whole and with their clinical effectiveness.

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Section: Local Effects Ofdilators In Arteries and Veinssupporting

confidence: 82%

Comparison of effects of tolmesoxide (RX71107), diazoxide, hydrallazine, prazosin, glyceryl trinitrate and sodium nitroprusside on forearm arteries and dorsal hand veins of man.

Collier¹,

Lorgé²,

Robinson³

1978

Brit J Clinical Pharma

122

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“…On the other hand, isoprenaline (Johnsson & Oberg, 1968) and hydralazine (Ablad & Mellander, 1963) had more pronounced dilator effects on precapillary resistance vessels; this, by decreasing the pre-to post-capillary resistance ratio, favoured transcapillary exchange. There are studies on the human forearm that also indicate that the main site of action of nitroglycerin is on capacitance vessels (Mason & Braunwald, 1965;Williams et al, 1965).…”

Section: Discussionmentioning

confidence: 99%

COMPARATIVE EFFECTS OF GLYCERYL TRINITRATE ON VENOUS AND ARTERIAL SMOOTH MUSCLE in vitro; RELEVANCE TO ANTIANGINAL ACTIVITY

Mackenzie

Parratt

1977

British J Pharmacology

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A quantitative in vitro study has been made of the actions of glyceryl trinitrate and sodium nitrite on vascular smooth muscle (dog femoral artery and saphenous vein; rat portal vein); these have been compared with the actions of papaverine, isoprenaline, salbutamol, pentaerythritol tetranitrate and trimetazidine. Glyceryl trinitrate was more active on the saphenous vein than on the femoral artery in inhibiting noradrenaline and potassium‐induced tone. Unlike glyceryl trinitrate, sodium nitrite and isoprenaline, papaverine and diazoxide inhibited noradrenaline‐induced contractions of venous and arterial smooth muscle to the same extent. The selective dilator effects of glyceryl trinitrate on venous smooth muscle may explain its action in alleviating the pain of angina pectoris. It is suggested that the use of these three vascular smooth muscle preparations (arterial, and veins with and without spontaneous myogenic activity) is a useful initial screening procedure for prospective antianginal drugs acting by venodilatation.

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“…The ratio of precapillary to postcapillary resistance is unaltered after nitrate administration, suggesting equivalent effects on arterioles and venules. 43 However, the dominant cardiovascular effect of nitroglycerin is on the venous bed ("capacitance vessels")." By comparison, the effects of amyl nitrite on the capacitance vessels are controversial;42 both decreased"4 and increased44 venous tone have been reported in man.…”

Section: Discussionmentioning

confidence: 99%

Influence of right ventricular hemodynamics on left ventricular diastolic pressure-volume relations in man.

Ludbrook¹,

Byrne²,

McKnight³

1979

Circulation

122

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SUMMARY To clarify the mechanism of displacement of the left ventricular diastolic pressure-volume function with alteration of loading conditions, the effects of nitroglycerin on pressure-volume relations in 13 patients were compared with those of amyl nitrite in 13 other patients during cardiac catheterization. After nitroglycerin, average systemic mean arterial pressure declined by 15.1 mm Hg (17%) and left ventricular enddiastolic pressure by 9.4 mm Hg (49%); right ventricular systolic and end-diastolic pressures fell 11.6 mm Hg (36%) and 5 mm Hg (41%), respectively. In all patients diastolic pressure-volume curves were significantly displaced downward and leftward. After amyl nitrite, average systemic mean arterial pressure fell 20.1 mm Hg (22%), but left ventricular end-diastolic pressure and right ventricular systolic and end-diastolic pressures were not significantly reduced. No significant displacement of diastolic pressure-volume curves occurred. Both the rate constant of the exponentially fit diastolic pressure-volume curve, and the rate of diastolic isovolumic relaxation (T) were unchanged after each drug. Thus downward displacement of diastolic pressure-volume functions after nitroglycerin appears to be dependent more upon reduction of right ventricular filling dynamics than coronary perfusion pressures. More favorable effects upon left ventricular function may be associated with reduction of both left ventricular filling pressures and systemic impedance (reflecting both "preload" and "afterload") than of systemic arterial pressures ("afterload") alone.

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Comparative Effects of Hydralazine, Sodium Nitrite and Acetylcholine on Resistance and Capacitance Blood Vessels and Capillary Filtration in Skeletal Muscle in the Cat

Cited by 71 publications

References 10 publications

Comparison of effects of tolmesoxide (RX71107), diazoxide, hydrallazine, prazosin, glyceryl trinitrate and sodium nitroprusside on forearm arteries and dorsal hand veins of man.

Comparison of effects of tolmesoxide (RX71107), diazoxide, hydrallazine, prazosin, glyceryl trinitrate and sodium nitroprusside on forearm arteries and dorsal hand veins of man.

COMPARATIVE EFFECTS OF GLYCERYL TRINITRATE ON VENOUS AND ARTERIAL SMOOTH MUSCLE in vitro; RELEVANCE TO ANTIANGINAL ACTIVITY

Influence of right ventricular hemodynamics on left ventricular diastolic pressure-volume relations in man.

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