In rabbit pulmonary artery smooth muscle, noradrenaline-induced contraction depends on the absolute membrane potential rather than the extent of depolarization.
Does not inform clinical vasoconstrictor use; leaves open whether absolute membrane potential governs adrenergic responses in human vessels.
In strips of rabbit main pulmonary artery, full dose-response curves of noradrenaline for the mechanical and electrical responses of the vascular smooth muscle cells were obtained under normal conditions and after increasing and decreasing the membrane potential with strychnine and tetraethylammonium, respectively. The results suggest that the magnitude of the noradrenaline-induced contraction is related to the height of the membrane potential and not to the degree of depolarization produced by the adrenergic transmitter.
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Guenther Haeusler (2008) studied this question.
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