Effects of Epinephrine, Nor-Epinephrine and Khellin on Circulation Through Isolated Perfused Hearts

Leusen, I; Essex, Hiram E.

doi:10.1152/ajplegacy.1952.172.1.226

Cited by 12 publications

(1 citation statement)

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“…It was only evident when these were clearly defined and the tension developed was about doubled. This investigation confirms that the guinea-pig isolated heart is approximately equally sensitive to adrenaline and noradrenaline (Leusen & Essex, 1953), the latter occasionally produced a slightly greater force increase and when this was so, it also produced the greater dilator response. Whether increases in rate or in force are more important in controlling the dilatation was difficult to determine.…”

Section: Discussionsupporting

confidence: 80%

An analysis of the coronary vascular responses to catecholamines, using a modified Langendorff heart preparation

Broadley¹

1970

British J Pharmacology

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Summary1. A modified Langendorff heart preparation from the guinea-pig was used to analyse catecholamine responses. Contractile force, heart rate and coronary perfusion pressure were recorded. 2. Four components of the vascular response could be identified.(a) The initial phase was a vasoconstriction mediated by a-adrenoceptors which preceded any effects on heart rate and force. (b) A secondary constriction followed, which was due to the increased myocardial compression during positive inotropic and chronotropic responses.(c) The third, more predominant, effect was a prolonged dilatation probably associated with the increased metabolic activity of the heart. (d) A fourth component was a direct vasodilatation mediated by /3-adrenoceptors which was evident when small doses of catecholamines were used but was usually masked by the more pronounced metabolically linked dilatation. 3. The actions of salbutamol were examined and since it caused direct vasodilatation by stimulation of /8-adrenoceptors without other myocardial effects, these adrenoceptors were classified as the fl2-type. 4. I.C.I. 50,172 was employed to block selectively the myocardial effects due to stimulation of f31-adrenoceptors and leave the vasodilator /32-adrenoceptors unaffected.5. Adrenaline, noradrenaline and isoprenaline were compared at two dose levels, in the presence or absence of effects on heart rate and force. 6. Constrictor or dilator effects were found in the absence of other effects and were shown to depend to some extent on the rate of coronary perfusion. IntroductionThe overall effect of catecholamines on the coronary circulation is vasodilatation

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Section: Discussionsupporting

confidence: 80%