title: Effects of noradrenaline, the calcium ionophore A23187, forskolin, sodium nitroprusside and glibenclamide on the degradation of extracellular adenosine 5'-triphosphate by the rat isolated vas deferens.
abstract: 1. The effects of noradrenaline (NA), the calcium ionophore A23187, forskolin, sodium nitroprusside (SNP) and the K+-channel blocker glibenclamide on the degradation by ectonucleotidases of extracellular adenosine 5'-triphosphate (ATP) were studied in the rat vas deferens. 2. ATP (100 microM) was rapidly broken down by the rat vas deferens with a half-life of 5.83 +/- 0.40 min via adenosine 5'-diphosphate (ADP) and adenosine 5'-monophosphate (AMP), with the final degradation product being inosine and with little adenosine being detected in the samples. 3. Preincubation for 1 h with NA (10 microM), A23187 (10 microM), or glibenclamide (100 microM) had no significant effect on the breakdown of ATP or the production of metabolites. However, both forskolin (10 microM) and SNP (1 microM) significantly increased the concentrations of AMP detected with time. In the case of SNP (1 microM) there was also a significant reduction in the rate of production of inosine, while in the case of forskolin (10 microM) there was a significant increase in the rate of removal of ATP. 4. These results suggest that preincubation with SNP may inhibit 5'-nucleotidase and so reduce the metabolism of AMP, while preincubation with forskolin may increase the activity of the ectonucleotidases responsible for production of AMP from ATP.
authors.affiliation: School of Biological Sciences, University of Surrey, Guildford, UK.
authors.forename: J P
authors.initials: JP
authors.lastname: Tennant
authors.forename: A
authors.initials: A
authors.lastname: Pearson
authors.forename: S M
authors.initials: SM
authors.lastname: Hourani
mesh_terms: D015720:5'-Nucleotidase / Q000502:physiology*; D000244:Adenosine Diphosphate / Q000032:analysis; D000249:Adenosine Monophosphate / Q000032:analysis; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D005905:Glyburide / Q000494:pharmacology; D007288:Inosine / Q000032:analysis; D008297:Male; D009599:Nitroprusside / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D014649:Vas Deferens / Q000187:drug effects* / Q000378:metabolism*
chemical_list: D009599:Nitroprusside; D005576:Colforsin; D000001:Calcimycin; D000249:Adenosine Monophosphate; D007288:Inosine; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D015720:5'-Nucleotidase; D005905:Glyburide; D009638:Norepinephrine