(1) The nutritional quality of strawberry (Fragaria × ananassa Duch) fruits, among others, is largely maintained by the presence of soluble sugars and organic acids. As the primary products of photosynthesis, they are energy depots in plants, necessary for the construction of cell constituents, but also serve as precursors of aromatic compounds and signaling molecules. (2) In this study, fruits of 25 strawberry cultivars were qualitatively and quantitatively characterized concerning individual sugars and organic acids by HPLC, FT-ICR-MS, and MS imaging analysis. In addition, the total quality index (TQI), as a novel mathematical model, was used to compare all individual parameters evaluated to obtain a quantitative single score, as an indicator of overall fruit quality. (3) Regardless of a large number of cultivars and monitored parameters that were studded, several cultivars stood out in terms of selected primary metabolites, such as ‘Rumba’, ‘Jeny’, and ‘Sandra’, while the latter had the best TQI score. (4) Intercultivar variations in sugars and organic acids profiles, along with other bioactive compounds, should be considered for selection of promising cultivars with improved naturally occurring nutraceutical traits. Besides the search for a pleasant taste, increased awareness of healthy nutrition resulted in heightening consumer demand for high-quality fruit.

2-2'Pyridylisatogen tosylate (PIT), which antagonizes the inhibitory action of ATP in the taenia caeci, did not antagonize the excitatory effects of exogenous ATP and of purinergic stimulation of the terminal guinea-pig ileum. PIT (0.5-2.5 PM) potentiated the ATP-induced contractions and also the contractions produced by potassium chloride, though the potentiation could not be related to the dose in every experiment. The responses to noradrenaline, adrenaline and histamine were slightly inhibited. PIT also potentiated the contractions produced by electrical stimulation of intramural purinergic nerves when either an alternate or uniform stimulation pattern was used. The present results in which the preparation is contracted by ATP are opposite to those obtained with PIT on the taenia caeci, which is relaxed by ATP. This raises a question of duality or plurality of receptors for ATP.

1 An interaction between adenosine triphosphate (ATP) and noradrenaline (NA) was investigated in the isolated vas deferens of the guinea-pig. 2 ATP (1.7 to 50 microM) enhanced contractions due to transmural electrical stimulation (ES; parameters: 30 Hz, 0.2 to 0.3 ms, 10 to 30 V; 1 s train duration). Responses to exogenous NA (12 microM) were also potentiated by ATP while contractions to acetylcholine (6 microM) were inhibited. 3 NA (1.2 microM) potentiated ATP-induced contractions and prevented the development of tachyphylaxis to ATP (510 microM). 4 Phentolamine (12.5 microM) prevented the potentiation by NA of ATP-induced contractions; these contractions were insensitive to phentolamine (up to 25 microM). 5 Removal of potassium chloride from the Tyrode solution for 10 min abolished the potentiating actions of both ATP and NA. 6 The present results suggest that the effect of ATP may be functionally closely related to that of NA at alpha-adrenoceptors in the vas deferens of the guinea-pig.

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