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Effect of diadenosine polyphosphates on catecholamine secretion from isolated chromaffin cells
Author(s) -
Castro E.,
Torres M.,
MirasPortugal M.T.,
Gonzalez M.P.
Publication year - 1990
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1990.tb15809.x
Subject(s) - catecholamine , chemistry , extracellular , secretion , nicotine , endocrinology , medicine , basal (medicine) , inhibitory postsynaptic potential , mechanism of action , biochemistry , biology , in vitro , insulin
1 The action of several diadenosine polyphosphates (AP 3 A, AP 4 A and AP 5 A) on basal, and on nicotine‐and high K + ‐evoked, catecholamine (CA) release has been investigated. Each of the three diadenosine polyphosphates weakly but significantly increased basal CA secretion. This enhancement represented about 10% of the response evoked by 2 μ m nicotine. 2 The evoked secretory response to diadenosine polyphosphates had an absolute requirement for extracellular Ca 2+ . 3 In contrast, these compounds had an inhibitory action on nicotine‐evoked release. This response was concentration‐dependent, EC 50 values being 3.2 ± 0.4 μ m , 4.0 ± 1.6 μ m and 19.3 ± 4.0 μ m for AP 3 A, AP 4 A, and AP 5 A, respectively. The lower the concentration of nicotine used to evoke secretion, the higher the inhibitory power of these compounds. 4 The CA secretion evoked by K + ‐rich solutions was further enhanced by AP 3 A and AP 5 A, whereas AP 4 A inhibited it. The possible physiological role of these dual actions is discussed.