Discrimination between UTP- and P2-purinoceptor-mediated depolarization of rat superior cervical ganglia by 4,4'-diisothiocyanatostilbene-2,2'- disulphonate (DIDS) and uniblue A.
1. Using a grease-gap recording technique we have investigated the effects of some antagonists of P2-purinoceptors on the depolarization of the rat isolated superior cervical ganglion evoked by 100 microM alpha, beta-methylene-adenosine 5'-triphosphate (alpha,beta-MeATP) or uridine 5'-triphosphate (UTP). The effects of the putative P2Z-purinoceptor antagonist, coomassie brilliant blue G, putative P2X-purinoceptor antagonist, 4,4'-diisothiocyanatostilbene-2,2'-disulphonate (DIDS) and uniblue A (an analogue of the P2Y- and P2X-purinoceptor antagonist reactive blue 2) were investigated. 2. At the highest concentration examined uniblue A (300 microM) depressed alpha,beta-MeATP-induced depolarization and at 100 and 300 microM enhanced UTP-evoked depolarizations. Coomassie brilliant blue G (1 and 10 microM) did not affect depolarizations evoked by alpha,beta-MeATP or UTP. Depolarizations evoked by potassium (5 mM) or muscarine (100 nM) were unaltered by either coomassie brilliant blue G or uniblue A. Uniblue A (100 and 300 microM) produced a concentration-dependent depression of hyperpolarizations evoked by adenosine (100 microM) whereas coomassie brilliant blue G at up to 10 microM, did not alter adenosine-induced hyperpolarizations. 3. DIDS (30 and 100 microM) did not alter adenosine-evoked hyperpolarizations, or depolarizations evoked by potassium or UTP. DIDS at 100 microM did not alter depolarizations evoked by muscarine. In contrast DIDS produced a concentration-dependent depression of alpha,beta-MeATP-evoked depolarizations. 4. These results are consistent with the proposal that uniblue A and DIDS but not coomassie brilliant blue G are antagonists of P2-purinoceptors and that uniblue A is also an antagonist at P1-purinoceptors present on the rat superior cervical ganglion. 5. The ability of uniblue A and DIDS to distinguish between depolarizations evoked by UTP and alpha,beta-MeATP provides further justification for the proposal that these nucleotides activate separate receptors present on the rat superior cervical ganglion, i.e. pyrimidinoceptors and P2-purinoceptors respectively.
Connolly
G P
GP
Department of Physiology, University College London.
Harrison
P J
PJ
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000737:chemistry / Q000494:pharmacology*; D000241:Adenosine / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D000880:Anthraquinones / Q000494:pharmacology*; D001557:Benzenesulfonates / Q000737:chemistry / Q000494:pharmacology; D004396:Coloring Agents / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005071:Evoked Potentials / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009116:Muscarine / Q000494:pharmacology; D058919:Purinergic P2 Receptor Antagonists; D051381:Rats; D017208:Rats, Wistar; D018048:Receptors, Purinergic P2 / Q000502:physiology*; D013329:Structure-Activity Relationship; D013451:Sulfonic Acids / Q000494:pharmacology*; D017783:Superior Cervical Ganglion / Q000187:drug effects* / Q000378:metabolism; D014227:Triazines / Q000737:chemistry / Q000494:pharmacology; D014544:Uridine Triphosphate / Q000494:pharmacology
D000880:Anthraquinones; D001557:Benzenesulfonates; D004396:Coloring Agents; D058919:Purinergic P2 Receptor Antagonists; D018048:Receptors, Purinergic P2; D013451:Sulfonic Acids; D014227:Triazines; C096133:uniblue A; C012842:Cibacron Blue F 3GA; D009116:Muscarine; D000255:Adenosine Triphosphate; C006796:brilliant blue; D000241:Adenosine; C002630:alpha,beta-methyleneadenosine 5'-triphosphate; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D014544:Uridine Triphosphate