title: Pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid can antagonize the purinoceptor-mediated inhibition of M-current in bullfrog sympathetic neurons.
abstract: Whole-cell recordings of an M-type potassium current (I(M)) were made from dissociated bullfrog sympathetic neurons. Purinoceptor agonists inhibited I(M) with UTP>ADP>adenosine triphosphate=UDP>ATPgammaS=guanosine triphosphate (GTP)>>amyloid precursor protein (APP)(NH)P as the rank order of potency. The IC(50) was 35 nM for UTP, and 2.6 microM for GTP. Under conditions in which I(M) was abolished by UTP (1 microM), a sulfonic acid derivative, pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS) (30-300 microM) recruited I(M) to 15 to 90% of its control in a reversible and concentration-dependent manner. These results indicate that PPADS can be useful as an antagonist for the purinoceptors presumably P2Y subtypes in amphibian autonomic neurons.
authors.affiliation: Department of Physiology, Tokai University School of Medicine, Bohseidai, Isehara 259-1193, Japan.
authors.forename: Hongxu
authors.initials: H
authors.lastname: Meng
authors.forename: Manabu
authors.initials: M
authors.lastname: Sakakibara
authors.forename: Hiroe
authors.initials: H
authors.lastname: Nakazawa
authors.forename: Takayuki
authors.initials: T
authors.lastname: Tokimasa
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D016564:Amyloid beta-Protein Precursor / Q000494:pharmacology; D000818:Animals; D006160:Guanosine Triphosphate / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D058914:Purinergic Antagonists; D011732:Pyridoxal Phosphate / Q000031:analogs & derivatives* / Q000494:pharmacology*; D011892:Rana catesbeiana; D011983:Receptors, Purinergic / Q000187:drug effects / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000502:physiology*; D014530:Uridine Diphosphate / Q000494:pharmacology; D014544:Uridine Triphosphate / Q000494:pharmacology
chemical_list: D016564:Amyloid beta-Protein Precursor; D015221:Potassium Channels; D058914:Purinergic Antagonists; D011983:Receptors, Purinergic; C077792:pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid; D014530:Uridine Diphosphate; D011732:Pyridoxal Phosphate; D000244:Adenosine Diphosphate; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D014544:Uridine Triphosphate