Summary
The effects of DPI on transmitter noradrenaline release were examined in rabbit isolated ear arteries previously incubated in [3H]noradrenaline. DPI (0.1 μmol/l) reduced transmitter release with periarterial electrical stimulation at 1 Hz (1 ms pulses, supramaximal voltage for 30 s), which is consistent with an agonistic effect of DPI on prejunctional α-adrenoceptors. At stimulation frequencies of 2 or 5 Hz DPI alone did not affect release, however in the presence of phentolamine (3 μmol/l, which increased release per se) DPI again significantly reduced release; this effect was blocked by metoclopramide (1 μmol/l) indicating an agonistic effect of DPI on prejunctional dopamine receptors.
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Medgett, I.C. Effects of DPI (2-(3,4-Dihydroxyphenylimino)-imidazolidine) on prejunctional α-adrenoceptors and prejunctional dopamine receptors in the rabbit ear artery. Naunyn-Schmiedeberg's Arch. Pharmacol. 323, 141–144 (1983). https://doi.org/10.1007/BF00634261
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DOI: https://doi.org/10.1007/BF00634261