AbstractPGE1, PGE2and PGF2αin concentrations ranging from 3×10‐9M to 1.5 × 10‐6M were infused into the isolated perfused, sympathetically innervated rabbit heart in order to assess their capacity to inhibit the chronotropic, inotropic and noradrenaline overflow responses to sympathetic nerve stimulation, as well as the chronotropic and inotropic responses to infusion of noradrenaline. The coronary flow was increased by PGE1but not by PGE2of PGF2α. The three compounds did not change the heart rate or the contractile force, indicating that the reported increase in heart rate after i.v. infusion of PGE1or PGE2is reflex in origin. PGE1and PGE2inhibited the outflow of noradrenaline as well as the chronotropic and inotropic responses to nerve stimulation in a dose‐dependent way, while PGF2αwas ineffective. None of the compounds altered the chronotropic or inotropic response to exogenous noradrenaline. It is concluded that PGE1and PGE2but not PGF2α, inhibit the sympathetic neurotransmission in the rabbit heart, and that they do this mainly by reducing the release of the transmitter from the adrenergic nerv
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