Premium
Differentiation by pyridoxal 5‐phosphate, PPADS and IsoPPADS between responses mediated by UTP and those evoked by α,β‐methylene‐ATP on rat sympathetic ganglia
Author(s) -
Connolly Gerald P.
Publication year - 1995
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.1476-5381.1995.tb17199.x
Subject(s) - ppads , purinergic receptor , adenosine , p2 receptor , uridine triphosphate , muscarine , superior cervical ganglion , medicine , endocrinology , adenosine triphosphate , depolarization , chemistry , biology , biochemistry , receptor , nucleotide , muscarinic acetylcholine receptor , gene
1 The effect of pyridoxal 5‐phosphate, and the 2′,4′ and 2′,5′‐disulphonic acid isomers of 6‐azophenyl‐pyridoxal 5‐phosphate (PPADS and IsoPPADS respectively) on depolarization of the rat superior cervical ganglion evoked by α,β‐methylene‐adenosine 5′‐triphosphate (α,β‐Me‐ATP) and uridine 5′‐triphosphate (UTP) were determined by a grease‐gap recording technique. 2 Pyridoxal 5‐phosphate (10–100 μ m ) and PPADS (10–100 μ m ) enhanced UTP‐ and depressed α,β‐Me‐ATP‐evoked depolarizations but did not significantly alter depolarizations evoked by potassium or hyperpolarizations evoked by adenosine. IsoPPADS (10 μ m ) depressed α,β‐Me‐ATP‐evoked depolarizations but did not alter depolarizations evoked by UTP. Depolarizations evoked by muscarine were depressed by IsoPPADS but not by pyridoxal 5‐phosphate. 3 It is concluded that pyridoxal 5‐phosphate, PPADS and IsoPPADS are antagonists at P 2X ‐purinoceptors but not at the receptors that mediate UTP‐evoked depolarization of the rat superior cervical ganglion. These observations substantiate the recent proposal that the rat superior cervical ganglia possess distinct receptors for purine and pyrimidine 5′‐nucleotides, i.e. P 2X ‐purinoceptors and pyrimidinoceptors respectively.